Search

Study design: Single-centre, two-parallel group, methodological randomised controlled trial to assess blinding feasibility. Background: Trials of manual therapy interventions of the back face methodological challenges regarding blinding feasibility and success. We assessed the feasibility of blinding an active manual soft tissue mobilisation and control intervention of the back. We also assessed whether blinding is feasible among outcome assessors and explored factors influencing perceptions about intervention assignment. Methods: On 7–8 November 2022, 24 participants were randomly allocated (1:1 ratio) to active or control manual interventions of the back. The active group (n = 11) received soft tissue mobilisation of the lumbar spine. The control group (n = 13) received light touch over the thoracic region with deep breathing exercises. The primary outcome was blinding of participants immediately after a one-time intervention session, as measured by the Bang blinding index (Bang BI). Bang BI ranges from –1 (complete opposite perceptions of intervention received) to 1 (complete correct perceptions), with 0 indicating 'random guessing'—balanced 'active' and 'control' perceptions within an intervention arm. Secondary outcomes included blinding of outcome assessors and factors influencing perceptions about intervention assignment among both participants and outcome assessors, explored via thematic analysis. Results: 24 participants were analysed following an intention-to-treat approach. 55% of participants in the active manual soft tissue mobilisation group correctly perceived their group assignment beyond chance immediately after intervention (Bang BI: 0.55 [95% confidence interval (CI), 0.25 to 0.84]), and 8% did so in the control group (0.08 [95% CI, −0.37 to 0.53]). Bang BIs in outcome assessors were 0.09 (−0.12 to 0.30) and −0.10 (−0.29 to 0.08) for active and control participants, respectively. Participants and outcome assessors reported varying factors related to their perceptions about intervention assignment. Conclusions: Blinding of participants allocated to an active soft tissue mobilisation of the back was not feasible in this methodological trial, whereas blinding of participants allocated to the control intervention and outcome assessors was adequate. Findings are limited due to imprecision and suboptimal generalisability to clinical settings. Careful thinking and consideration of blinding in manual therapy trials is warranted and needed. Trial registration: ClinicalTrials.gov: NCT05822947 (retrospectively registered) [ABSTRACT FROM AUTHOR]

Background: Suicide is a major and complex public health problem. In Switzerland, suicide accounts for about 1000 deaths yearly and is the fourth leading cause of mortality. The first nationwide Swiss study of suicides identified eight male and four female occupations with statistically significant excess of suicide compared to the general Swiss population. Working time, self-employer status, low socio-economic status and low skill level required for occupation were associated with increase in suicide risk. Presently, we aim to compare the distribution of suicide risk across occupations with the prevalence of somatic and psychiatric morbidity in Swiss working-aged adults. We hypothesized that some diseases would cluster in particular occupations, indicating potential work-relatedness of suicides found in these occupations. Methods: We used the Swiss National Cohort (SNC) and included 10575 males and 2756 females deceased by suicide between 1990 and 2014. We estimated the prevalence of 16 categories of concomitant diseases in each occupation, using national mortality records, and assessed the homogeneity of diseases distribution across occupations. For diseases, which prevalence varied significantly across occupations, we analyzed the correlation with the distribution of suicide risk, estimated as the standardized mortality ratio (SMR) of suicide. Results: Mental and behavioral disorders were the most commonly reported concomitant diseases in our population. In men, the prevalence of these disorders and more specifically, the prevalence of substance-related and addictive disorders, and of psychotic disorders varied significantly across occupations and was correlated with the SMR of suicide. The prevalence of malignant neoplasms and the prevalence of diseases of the musculoskeletal system and connective tissue also varied significantly across male occupations, while in women, such a variation was observed for neoplasms of uncertain or unknown behavior and diseases of the nervous system and sense organs, without being correlated with the SMR of suicide. Conclusion: Some of the identified morbidities can be occupation-related and could negatively affect the working capacity and the employability, which in turn could be related to the suicide. Disentangling concomitant diseases according to their work-relatedness and relationship with the suicide risk is important for identifying occupation-related suicides, understanding their characteristics, and developing appropriated interventions for their prevention. [ABSTRACT FROM AUTHOR]

Background: Physical inactivity across the lifespan remains a public health issue for many developed countries. Inactivity has contributed considerably to the pervasiveness of lifestyle diseases. Government, national and local agencies and organizations have been unable to systematically, and in a coordinated way, translate behavioral research into practice that makes a difference at a population level. One approach for mobilizing multi-level efforts to improve the environment for physical activity is to engage in a process of citizen science. Citizen Science here is defined as a participatory research approach involving members of the public working closely with research investigators to initiate and advance scientific research projects. However, there are no common measures or protocols to guide citizen science research at the local community setting. Objectives: We describe overarching categories of constructs that can be considered when designing citizen science projects expected to yield multi-level interventions, and provide an example of the citizen science approach to promoting PA. We also recommend potential measures across different levels of impact. Discussion: Encouraging some consistency in measurement across studies will potentially accelerate the efficiency with which citizen science participatory research provides new insights into and solutions to the behaviorally-based public health issues that drive most of morbidity and mortality. The measures described in this paper abide by four fundamental principles specifically selected for inclusion in citizen science projects: feasibility, accuracy, propriety, and utility. The choice of measures will take into account the potential resources available for outcome and process evaluation. Our intent is to emphasize the importance for all citizen science participatory projects to follow an evidence-based approach and ensure that they incorporate an appropriate assessment protocol. Conclusions: We provided the rationale for and a list of contextual factors along with specific examples of measures to encourage consistency among studies that plan to use a citizen science participatory approach. The potential of this approach to promote health and wellbeing in communities is high and we hope that we have provided the tools needed to optimally promote synergistic gains in knowledge across a range of Citizen Science participatory projects. [ABSTRACT FROM AUTHOR]

Background: COPD prevalence is highly variable and geographical altitude has been linked to it, yet with conflicting results. We aimed to investigate this association, considering well known risk factors.Methods: A pooled analysis of individual data from the PREPOCOL-PLATINO-BOLD-EPI-SCAN studies was used to disentangle the population effect of geographical altitude on COPD prevalence. Post-bronchodilator FEV1/FVC below the lower limit of normal defined airflow limitation consistent with COPD. High altitude was defined as >1500 m above sea level. Undiagnosed COPD was considered when participants had airflow limitation but did not report a prior diagnosis of COPD.Results: Among 30,874 participants aged 56.1 ± 11.3 years from 44 sites worldwide, 55.8% were women, 49.6% never-smokers, and 12.9% (3978 subjects) were residing above 1500 m. COPD prevalence was significantly lower in participants living at high altitude with a prevalence of 8.5% compared to 9.9%, respectively (p < 0.005). However, known risk factors were significantly less frequent at high altitude. Hence, in the adjusted multivariate analysis, altitude itself had no significant influence on COPD prevalence. Living at high altitude, however, was associated with a significantly increased risk of undiagnosed COPD. Furthermore, subjects with airflow limitation living at high altitude reported significantly less respiratory symptoms compared to subjects residing at lower altitude.Conclusion: Living at high altitude is not associated with a difference in COPD prevalence after accounting for individual risk factors. However, high altitude itself was associated with an increased risk of undiagnosed COPD. [ABSTRACT FROM AUTHOR]

Background: Prediction models in autosomal dominant polycystic kidney disease (ADPKD) are useful in clinical settings to identify patients with greater risk of a rapid disease progression in whom a treatment may have more benefits than harms. Mayo Clinic investigators developed a risk prediction tool for ADPKD patients using a single kidney value. Our aim was to perform an independent geographical and temporal external validation as well as evaluate the potential for improving the predictive performance by including additional information on total kidney volume.Methods: We used data from the on-going Swiss ADPKD study from 2006 to 2016. The main analysis included a sample size of 214 patients with Typical ADPKD (Class 1). We evaluated the Mayo Clinic model performance calibration and discrimination in our external sample and assessed whether predictive performance could be improved through the addition of subsequent kidney volume measurements beyond the baseline assessment.Results: The calibration of both versions of the Mayo Clinic prediction model using continuous Height adjusted total kidney volume (HtTKV) and using risk subclasses was good, with R2 of 78% and 70%, respectively. Accuracy was also good with 91.5% and 88.7% of the predicted within 30% of the observed, respectively. Additional information regarding kidney volume did not substantially improve the model performance.Conclusion: The Mayo Clinic prediction models are generalizable to other clinical settings and provide an accurate tool based on available predictors to identify patients at high risk for rapid disease progression. [ABSTRACT FROM AUTHOR]

The 1-min sit-to-stand (1-min STS) test and handgrip strength test have been proposed as simple tests of functional exercise performance in chronic obstructive pulmonary disease (COPD) patients. We assessed the long-term (5-year) predictive performance of the 1-min sit-to-stand and handgrip strength tests for mortality, health-related quality of life (HRQoL) and exacerbations in COPD patients. In 409 primary care patients, we found the 1-min STS test to be strongly associated with long-term morality (hazard ratio per 3 more repetitions: 0.81, 95% CI 0.65 to 0.86) and moderately associated with long-term HRQoL. Neither test was associated with exacerbations. Our results suggest that the 1-min STS test may be useful for assessing the health status and long-term prognosis of COPD patients. This study was registered at http://www.clinicaltrials.gov/ (NCT00706602, 25 June 2008). [ABSTRACT FROM AUTHOR]

Background: The practice of continuous deep sedation is a challenging clinical intervention with demanding clinical and ethical decision-making. Though current research indicates that healthcare professionals' involvement in such decisions is associated with emotional stress, little is known about sedation-related emotional burden. This study aims to systematically review the evidence on the impact of the inpatient practice of continuous deep sedation until death on healthcare professionals' emotional well-being. Methods: A systematic review of literature published between January 1990 and October 2016 was performed following a predefined protocol. MEDLINE, EMBASE, PubMed, Cochrane Library, CINAHL, Scopus, and PsycINFO were searched using search terms within "end-of-life care", "sedation", and "emotional well-being". Dissertations and reference lists were screened by hand. Two independent reviewers conducted study selection, data extraction and quality assessment. We abstracted measures of psychological outcomes, which were related to the practice of continuous deep sedation until death, including emotional well-being, stress and exhaustion. We used the GRADE approach to rate the quality of evidence. Results: Three studies remained out of 528 publications identified. A total of 3'900 healthcare professionals (82% nurses, 18% physicians) from Japan (n = 3384) and the Netherlands (n =16) were included. The prevalence of sedation-related burden in nurses varied from 11 to 26%, depending on outcome measure. Physicians showed medium levels of emotional exhaustion and low levels of depersonalization. Common clinical concerns contributing to professionals' burden were diagnosing refractory symptoms and sedation in the context of possibly life- shortening decisions. Non-clinical challenges included conflicting wishes between patients and families, disagreements within the care team, and insufficient professionals' skills and coping. Due to the limited results and heterogeneity in outcome measure, the GRADE ratings for the quality of evidence were low. Conclusions: Current evidence does not suggest that practicing continuous deep sedation is generally associated with lower emotional well-being of healthcare professionals. Higher emotional burden seems more likely when professionals struggled with clinical and ethical justifications for continuous deep sedation. This appeared to be in part a function of clinical experience. Further research is needed to strengthen this evidence, as it is likely that additional studies will change the current evidence base. [ABSTRACT FROM AUTHOR]

Background: Quality improvement in health care requires identification of areas in need of improvement by comparing processes and patient outcomes within and between health care providers. It is critical to adjust for different case-mix and outcome risks of patient populations but it is currently unclear which approach has higher validity and how limitations need to be dealt with. Our aim was to compare 3 approaches towards risk adjustment for 7 different major quality indicators in neonatal intensive care (21 models).Methods: We compared an indirect standardization, logistic regression and multilevel approach. Parameters for risk adjustment were chosen according to literature and the condition that they may not depend on processes performed by treating clinics. Predictive validity was tested using the mean Brier Score and by comparing area under curve (AUC) using high quality population based data separated into training and validation sets. Changes in attributional validity were analysed by comparing the effect of the models on the observed-to-expected ratios of the clinics in standardized mortality/morbidity ratio charts.Results: Risk adjustment based on indirect standardization revealed inferior c-statistics but superior Brier scores for 3 of 7 outcomes. Logistic regression and multilevel modelling were equivalent to one another. C-statistics revealed that predictive validity was high for 8 and acceptable for 11 of the 21 models. Yet, the effect of all forms of risk adjustment on any clinic's comparison with the standard was small, even though there was clear risk heterogeneity between clinics.Conclusions: All three approaches to risk adjustment revealed comparable results. The limited effect of risk adjustment on clinic comparisons indicates a small case-mix influence on observed outcomes, but also a limited ability to isolate quality improvement potential based on risk-adjustment models. Rather than relying on methodological approaches, we instead recommend that clinics build small collaboratives and compare their indicators both in risk-adjusted and unadjusted form together. This allows qualitatively investigating and discussing the residual risk-differences within networks. The predictive validity should be quantified and reported and stratification into risk groups should be more widely used to correct for confounding. [ABSTRACT FROM AUTHOR]

Public health research is complex, involves various disciplines, epistemological perspectives and methods, and is rarely conducted in a controlled setting. Often, the added value of a research project lies in its inter- or trans-disciplinary interaction, reflecting the complexity of the research questions at hand. This creates specific challenges when writing and reviewing public health research grant applications. Therefore, the German Research Foundation (DFG), the largest independent research funding organization in Germany, organized a round table to discuss the process of writing, reviewing and funding public health research. The aim was to analyse the challenges of writing, reviewing and granting scientific public health projects and to improve the situation by offering guidance to applicants, reviewers and funding organizations. The DFG round table discussion brought together national and international public health researchers and representatives of funding organizations. Based on their presentations and discussions, a core group of the participants (the authors) wrote a first draft on the challenges of writing and reviewing public health research proposals and on possible solutions. Comments were discussed in the group of authors until consensus was reached. Public health research demands an epistemological openness and the integration of a broad range of specific skills and expertise. Applicants need to explicitly refer to theories as well as to methodological and ethical standards and elaborate on why certain combinations of theories and methods are required. Simultaneously, they must acknowledge and meet the practical and ethical challenges of conducting research in complex real life settings. Reviewers need to make the rationale for their judgments transparent, refer to the corresponding standards and be explicit about any limitations in their expertise towards the review boards. Grant review boards, funding organizations and research ethics committees need to be aware of the specific conditions of public health research, provide adequate guidance to applicants and reviewers, and ensure that processes and the expertise involved adequately reflect the topic under review. [ABSTRACT FROM AUTHOR]

Background: Clinical practice guidelines provide separate recommendations for different diseases that may be prevented or treated by the same intervention. Also, they commonly provide recommendations for entire populations but not for individuals. To address these two limitations, our aim was to conduct benefit-harm analyses for a wide range of individuals using the example of low dose aspirin for primary prevention of cardiovascular disease and cancer and to develop Benefit-Harm Charts that show the overall benefit-harm balance for individuals.Methods: We used quantitative benefit-harm modeling that included 16 outcomes to estimate the probability that low dose aspirin provides more benefits than harms for a wide range of men and women between 45 and 84 years of age and without a previous myocardial infarction, severe ischemic stroke, or cancer. We repeated the quantitative benefit-harm modeling for different combinations of age, sex, and outcome risks for severe ischemic and hemorrhagic stroke, myocardial infarction, cancers, and severe gastrointestinal bleeds. The analyses considered weights for the outcomes, statistical uncertainty of the effects of aspirin, and death as a competing risk. We constructed Benefit-Harm Charts that show the benefit-harm balance for different combinations of outcome risks.Results: The Benefit-Harm Charts ( http://www.benefit-harm-balance.com ) we have created show that the benefit-harm balance differs largely across a primary prevention population. Low dose aspirin is likely to provide more benefits than harms in men, elderly people, and in those at low risk for severe gastrointestinal bleeds. Individual preferences have a major impact on the benefit-harm balance. If, for example, it is a high priority for individuals to prevent stroke and severe cancers while severe gastrointestinal bleeds are deemed to be of little importance, the benefit-harm balance is likely to favor low dose aspirin for most individuals. Instead, if severe gastrointestinal bleeds are judged to be similarly important compared to the benefit outcomes, low dose aspirin is unlikely to provide more benefits than harms.Conclusions: Benefit-Harm Charts support individualized benefit-harm assessments and decision making. Similarly, individualized benefit-harm assessments may allow guideline developers to issue more finely granulated recommendations that reduce the risk of over- and underuse of interventions. The example of low dose aspirin for primary prevention of cardiovascular disease and cancer shows that it may be time for guideline developers to provide combined recommendations for different diseases that may be prevented or treated by the same intervention. [ABSTRACT FROM AUTHOR]

Background: Many patients with chronic illness are limited in their physical activities. This systematic review evaluates the content and format of patient-reported outcome (PRO) questionnaires that measure physical activity in elderly and chronically ill populations. Methods: Questionnaires were identified by a systematic literature search of electronic databases (Medline, Embase, PsychINFO & CINAHL), hand searches (reference sections and PROQOLID database) and expert input. A qualitative analysis was conducted to assess the content and format of the questionnaires and a Venn diagram was produced to illustrate this. Each stage of the review process was conducted by at least two independent reviewers. Results: 104 questionnaires fulfilled our criteria. From these, 182 physical activity domains and 1965 items were extracted. Initial qualitative analysis of the domains found 11 categories. Further synthesis of the domains found 4 broad categories: 'physical activity related to general activities and mobility', 'physical activity related to activities of daily living', 'physical activity related to work, social or leisure time activities', and '(disease-specific) symptoms related to physical activity'. The Venn diagram showed that no questionnaires covered all 4 categories and that the '(disease-specific) symptoms related to physical activity' category was often not combined with the other categories. Conclusions: A large number of questionnaires with a broad range of physical activity content were identified. Although the content could be broadly organised, there was no consensus on the content and format of physical activity PRO questionnaires in elderly and chronically ill populations. Nevertheless, this systematic review will help investigators to select a physical activity PRO questionnaire that best serves their research question and context. [ABSTRACT FROM AUTHOR]

Background: When faced with uncertainties about the effects of medical interventions regulatory agencies, guideline developers, clinicians, and researchers commonly ask for more research, and in particular for more randomized trials. The conduct of additional randomized trials is, however, sometimes not the most efficient way to reduce uncertainty. Instead, approaches such as value of information analysis or other approaches should be used to prioritize research that will most likely reduce uncertainty and inform decisions. Discussion: In situations where additional research for specific interventions needs to be prioritized, we propose the use of quantitative benefit-harm assessments that illustrate how the benefit-harm balance may change as a consequence of additional research. The example of roflumilast for patients with chronic obstructive pulmonary disease shows that additional research on patient preferences (e.g., how important are exacerbations relative to psychiatric harms?) or outcome risks (e.g., what is the incidence of psychiatric outcomes in patients with chronic obstructive pulmonary disease without treatment?) is sometimes more valuable than additional randomized trials. Summary: We propose that quantitative benefit-harm assessments have the potential to explore the impact of additional research and to identify research priorities Our approach may be seen as another type of value of information analysis and as a useful approach to stimulate specific new research that has the potential to change current estimates of the benefit-harm balance and decision making. [ABSTRACT FROM AUTHOR]

Background: Risk-stratified treatment recommendations facilitate treatment decision-making that balances patientspecific risks and preferences. It is unclear if and how such recommendations are developed in clinical practice guidelines (CPGs). Our aim was to assess if and how CPGs develop risk-stratified treatment recommendations for the prevention or treatment of common chronic diseases. Methods: We searched the United States National Guideline Clearinghouse for US, Canadian and National Institute for Health and Clinical Excellence (United Kingdom) CPGs for heart disease, stroke, cancer, chronic obstructive pulmonary disease and diabetes that make risk-stratified treatment recommendations. We included only those CPGs that made risk-stratified treatment recommendations based on risk assessment tools. Two reviewers independently identified CPGs and extracted information on recommended risk assessment tools; type of evidence about treatment benefits and harms; methods for linking risk estimates to treatment evidence and for developing treatment thresholds; and consideration of patient preferences. Results: We identified 20 CPGs that made risk-stratified treatment recommendations out of 133 CPGs that made any type of treatment recommendations for the chronic diseases considered in this study. Of the included 20 CPGs, 16 (80%) used evidence about treatment benefits from randomized controlled trials, meta-analyses or other guidelines, and the source of evidence was unclear in the remaining four (20%) CPGs. Nine CPGs (45%) used evidence on harms from randomized controlled trials or observational studies, while 11 CPGs (55%) did not clearly refer to harms. Nine CPGs (45%) explained how risk prediction and evidence about treatments effects were linked (for example, applying estimates of relative risk reductions to absolute risks), but only one CPG (5%) assessed benefit and harm quantitatively and three CPGs (15%) explicitly reported consideration of patient preferences. Conclusions: Only a small proportion of CPGs for chronic diseases make risk-stratified treatment recommendations with a focus on heart disease and stroke prevention, diabetes and breast cancer. For most CPGs it is unclear how risk-stratified treatment recommendations were developed. As a consequence, it is uncertain if CPGs support patients and physicians in finding an acceptable benefit- harm balance that reflects both profile-specific outcome risks and preferences. [ABSTRACT FROM AUTHOR]

Introduction There are limited data on the efficacy of early fluid resuscitation with third generation hydroxyethyl starch (HES 130) in burn injury. Adverse effects of HES on survival and organ function have been reported. Methods In this randomized, controlled, double-blind trial 48 patients with severe burn injury were assigned to receive either Lactated Ringer's solution plus 6% HES 130/0.4 in a ratio of 2:1 or Lactated Ringer's solution with no colloid supplement for the first 72 hours. Primary outcome parameter was the group difference of administered total fluid from intensive care unit (ICU) admission up to day 3. Secondary outcomes included kidney and lung injury and failure, length of stay, and mortality. Results 3 days total of administered resuscitation fluid (medians) was 21,190 ml in the Lactated Ringer's group and 19,535 ml in the HES group (HES: -1,213 ml; P = 0.39). Creatinine levels day 1 to 3 (HES: +0.4 µmol/l; 95% CI -18.7 to 19.5; P = 0.97) and urinary output day 1 to 3 (HES: -58 ml; 95% CI -400 to 284; P = 0.90) were not different. 6 patients in each group developed acute respiratory distress syndrome (ARDS) (risk ratio 0.96; 95% CI 0.35 to 2.64; P = 0.95). Length of ICU stay (HES vs. Lactated Ringer's: 28 vs. 24 days; P = 0.80) and length of hospital stay (31 vs. 29 days; P = 0.57) were similar. 28-day mortality was 4 patients in each group (risk ratio 0.96; 95% CI 0.27 to 4.45; P = 0.95), in-hospital mortality was 8 in the HES group vs. 5 patients in the Lactated Ringer's group (hazard ratio 1.86; 95% CI 0.56 to 6.19; P = 0.31). Conclusions There was no evidence that early fluid resuscitation with balanced HES 130/0.4 (6%) in addition to Lactated Ringer's solution would lead to a volume sparing effect in severe burn injury. Together with the findings that early renal function, incidence of ARDS, length of stay, and mortality were not negatively influenced by HES in this setting, balanced HES 130/0.4 (6%) plus Lactated Ringer's solution could not be considered superior to Lactated Ringer's solution alone. [ABSTRACT FROM AUTHOR]

Background: Several quantitative approaches for benefit-harm assessment of health care interventions exist but it is unclear how the approaches differ. Our aim was to review existing quantitative approaches for benefit-harm assessment and to develop an organizing framework that clarifies differences and aids selection of quantitative approaches for a particular benefit-harm assessment. Methods: We performed a review of the literature to identify quantitative approaches for benefit-harm assessment. Our team, consisting of clinicians, epidemiologists, and statisticians, discussed the approaches and identified their key characteristics. We developed a framework that helps investigators select quantitative approaches for benefit-harm assessment that are appropriate for a particular decisionmaking context. Results: Our framework for selecting quantitative approaches requires a concise definition of the treatment comparison and population of interest, identification of key benefit and harm outcomes, and determination of the need for a measure that puts all outcomes on a single scale (which we call a benefit and harm comparison metric). We identified 16 quantitative approaches for benefit-harm assessment. These approaches can be categorized into those that consider single or multiple key benefit and harm outcomes, and those that use a benefit-harm comparison metric or not. Most approaches use aggregate data and can be used in the context of single studies or systematic reviews. Although the majority of approaches provides a benefit and harm comparison metric, only four approaches provide measures of uncertainty around the benefit and harm comparison metric (such as a 95 percent confidence interval). None of the approaches considers the actual joint distribution of benefit and harm outcomes, but one approach considers competing risks when calculating profile-specific event rates. Nine approaches explicitly allow incorporating patient preferences. Conclusion: The choice of quantitative approaches depends on the specific question and goal of the benefit-harm assessment as well as on the nature and availability of data. In some situations, investigators may identify only one appropriate approach. In situations where the question and available data justify more than one approach, investigators may want to use multiple approaches and compare the consistency of results. When more evidence on relative advantages of approaches accumulates from such comparisons, it will be possible to make more specific recommendations on the choice of approaches. [ABSTRACT FROM AUTHOR]

Background: In research with long-term follow-up and repeated measurements, quick and complete response to questionnaires helps ensure a study's validity, precision and efficiency. Evidence on the effect of non-monetary incentives on response rates in observational longitudinal research is scarce. Objectives: To study the impact of two strategies to enhance completeness and efficiency in observational cohort studies with follow-up durations of around 2 years. Method and intervention: In a factorial design, 771 children between 2 and 5 years old and their parents participating in a prospective cohort study were randomized to three intervention groups and a control group. Three types of lotteries were run: (i) daytrip tickets for the whole family to a popular amusement park if they returned all postal questionnaires, (ii) €12.50-worth gift vouchers for sending back the questionnaire on time after each questionnaire round and (iii) a combination of (i) and (ii). Main outcome measures: Primary outcome was the proportion of participants who returned all questionnaires without any reminder. Secondary outcomes were '100% returned with or without reminder', 'probability of 100% non-response', 'probability of withdrawal', 'proportion of returned questionnaires' and 'overall number of reminders sent'. Statistical analysis: After testing for interaction between the two lottery interventions, the two trials were analysed separately. We calculated risk differences (RD) and numbers needed to "treat" and their 95% confidence intervals. Results: Daytrip nor voucher intervention had an effect on the proportion of participants who returned all questionnaires (RD -0.01; 95% CI-0.07 - 0.06) and (RD 0.02; 95% CI-0.50 - 0.08), respectively. No effects were found on the secondary outcomes. Conclusion: Our findings do not support the idea that lottery-style incentives lead to more complete response to postal questionnaires in observational cohort studies with repeated data collection and follow-up durations of around 2 years. [ABSTRACT FROM AUTHOR]

The assessment of physical activity in healthy populations and in those with chronic diseases is challenging. The aim of this systematic review was to identify whether available activity monitors (AM) have been appropriately validated for use in assessing physical activity in these groups. Following a systematic literature search we found 134 papers meeting the inclusion criteria; 40 conducted in a field setting (validation against doubly labelled water), 86 in a laboratory setting (validation against a metabolic cart, metabolic chamber) and 8 in a field and laboratory setting. Correlation coefficients between AM outcomes and energy expenditure (EE) by the criterion method (doubly labelled water and metabolic cart/chamber) and percentage mean differences between EE estimation from the monitor and EE measurement by the criterion method were extracted. Random-effects meta-analyses were performed to pool the results across studies where possible. Types of devices were compared using meta-regression analyses. Most validation studies had been performed in healthy adults (n = 118), with few carried out in patients with chronic diseases (n = 16). For total EE, correlation coefficients were statistically significantly lower in uniaxial compared to multisensor devices. For active EE, correlations were slightly but not significantly lower in uniaxial compared to triaxial and multisensor devices. Uniaxial devices tended to underestimate TEE (-12.07 (95%CI; -18.28 to -5.85) %) compared to triaxial (-6.85 (95%CI; -18.20 to 4.49) %, p = 0.37) and were statistically significantly less accurate than multisensor devices (-3.64 (95%CI; -8.97 to 1.70) %, p<0.001). TEE was underestimated during slow walking speeds in 69% of the lab validation studies compared to 37%, 30% and 37% of the studies during intermediate, fast walking speed and running, respectively. The high level of heterogeneity in the validation studies is only partly explained by the type of activity monitor and the activity monitor outcome. Triaxial and multisensor devices tend to be more valid monitors. Since activity monitors are less accurate at slow walking speeds and information about validated activity monitors in chronic disease populations is lacking, proper validation studies in these populations are needed prior to their inclusion in clinical trials. [ABSTRACT FROM AUTHOR]

Background: Patient-reported outcomes are measured in many epidemiologic studies using self- or intervieweradministered questionnaires. While in some studies differences between these administration formats were observed, other studies did not show statistically significant differences important to patients. Since the evidence about the effect of administration format is inconsistent and mainly available from cross-sectional studies our aim was to assess the effects of different administration formats on repeated measurements of patient-reported outcomes in participants with AIDS enrolled in the Longitudinal Study of Ocular Complications of AIDS. Methods: We included participants enrolled in the Longitudinal Study of Ocular Complications in AIDS (LSOCA) who completed the Medical Outcome Study [MOS] -HIV questionnaire, the EuroQol, the Feeling Thermometer and the Visual Function Questionnaire (VFQ) 25 every six months thereafter using self- or interviewer-administration. A large print questionnaire was available for participants with visual impairment. Considering all measurements over time and adjusting for patient and study site characteristics we used linear models to compare HRQL scores (all scores from 0-100) between administration formats. We defined adjusted differences of ≥0.2 standard deviations [SD]) to be quantitatively meaningful. Results: We included 2,261 participants (80.6% males) with a median of 43.1 years of age at enrolment who provided data on 23,420 study visits. The self-administered MOS-HIV, Feeling Thermometer and EuroQol were used in 70% of all visits and the VFQ-25 in 80%. For eight domains of the MOS-HIV differences between the interviewer- and self- administered format were < 0.1 SD. Differences in scores were highest for the social and role function domains but the adjusted differences were still < 0.2 SD. There was no quantitatively meaningful difference between administration formats for EuroQol, Feeling Thermometer and VFQ-25 domain scores. For ocular pain (VFQ-25), we found a statistically significant difference of 3.5 (95% CI 0.2, 6.8), which did, however, not exceed 0.2 SD. For all instruments scores were similar for the large and standard print formats with all adjusted differences < 0.2 SD. Conclusions: Our large study provides evidence that administration formats do not have a meaningful effect on repeated measurements of patient-reported outcomes. As a consequence, longitudinal studies may not need to consider the effect of different administration formats in their analyses. [ABSTRACT FROM AUTHOR]

Background: The complexity of chronic diseases is a challenge for investigators conducting randomized trials. The causes for this include the often difficult control for confounding, the selection of outcomes from many potentially important outcomes, the risk of missing data with long follow-up and the detection of heterogeneity of treatment effects. Our aim was to assess such aspects of trial design and analysis for four prevalent chronic diseases. Methods: We included 161 randomized trials on drug and non-drug treatments for chronic obstructive pulmonary disease, type 2 diabetes mellitus, stroke and heart failure, which were included in current Cochrane reviews. We assessed whether these trials defined a single outcome or several primary outcomes, statistically compared baseline characteristics to assess comparability of treatment groups, reported on between-group comparisons, and we also assessed how they handled missing data and whether appropriate methods for subgroups effects were used. Results: We found that only 21% of all chronic disease trials had a single primary outcome, whereas 33% reported one or more primary outcomes. Two of the fifty-one trials that tested for statistical significance of baseline characteristics adjusted the comparison for a characteristic that was significantly different. Of the 161 trials, 10% reported a within-group comparison only; 17% (n = 28) of trials reported how missing data were handled (50% (n = 14) carried forward last values, 27% (n = 8) performed a complete case analysis, 13% (n = 4) used a fixed value imputation and 10% (n = 3) used more advanced methods); and 27% of trials performed a subgroup analysis but only 23% of them (n = 10) reported an interaction test. Drug trials, trials published after wide adoption of the CONSORT (CONsolidated Standards of Reporting Trials) statement (2001 or later) and trials in journals with higher impact factors were more likely to report on some of these aspects of trial design and analysis. Conclusion: Our survey showed that an alarmingly large proportion of chronic disease trials do not define a primary outcome, do not use appropriate methods for subgroup analyses, or use naïve methods to handle missing data, if at all. As a consequence, biases are likely to be introduced in many trials on widely prescribed treatments for patients with chronic disease. [ABSTRACT FROM AUTHOR]

Background: Chronic Obstructive Pulmonary Disease (COPD) is a systemic disease; morbidity and mortality due to COPD are on the increase, and it has great impact on patients' lives. Most COPD patients are managed by general practitioners (GP). Too often, GPs base their initial assessment of patient's disease severity mainly on lung function. However, lung function correlates poorly with COPD-specific health-related quality of life and exacerbation frequency. A validated COPD disease risk index that better represents the clinical manifestations of COPD and is feasible in primary care seems to be useful. The objective of this study is to develop and validate a practical COPD disease risk index that predicts the clinical course of COPD in primary care patients with GOLD stages 2-4. Methods/Design: We will conduct 2 linked prospective cohort studies with COPD patients from GPs in Switzerland and the Netherlands. We will perform a baseline assessment including detailed patient history, questionnaires, lung function, history of exacerbations, measurement of exercise capacity and blood sampling. During the follow-up of at least 2 years, we will update the patients' profile by registering exacerbations, health-related quality of life and any changes in the use of medication. The primary outcome will be health-related quality of life. Secondary outcomes will be exacerbation frequency and mortality. Using multivariable regression analysis, we will identify the best combination of variables predicting these outcomes over one and two years and, depending on funding, even more years. Discussion: Despite the diversity of clinical manifestations and available treatments, assessment and management today do not reflect the multifaceted character of the disease. This is in contrast to preventive cardiology where, nowadays, the treatment in primary care is based on patient-specific and fairly refined cardiovascular risk profile corresponding to differences in prognosis. After completion of this study, we will have a practical COPD-disease risk index that predicts the clinical course of COPD in primary care patients with GOLD stages 2-4. In a second step we will incorporate evidence-based treatment effects into this model, such that the instrument may guide physicians in selecting treatment based on the individual patients' prognosis. Trial registration: ClinicalTrials.gov Archive NCT00706602 [ABSTRACT FROM AUTHOR]

Background: The feasibility of randomized trials often depends on successful patient recruitment. Although numerous recruitment barriers have been identified it is unclear which of them complicate recruitment most. Also, most surveys have focused on the patients' perspective of recruitment barriers whereas the perspective of recruiting physicians has received less attention. Therefore, our aim was to conduct a postal survey among recruiting physicians of a multi-center trial to weigh barriers according to their impact on recruitment. Methods: We identified any potential recruitment barriers from the literature and from our own experience with a multi-center trial of respiratory rehabilitation in patients with chronic obstructive pulmonary disease. We developed and pilot-tested a self-administered questionnaire where recruiting physicians were asked to express their agreement with statements about recruitment barriers on a Likert-type scale from 1 (full agreement with statement = very substantial recruitment barrier) to 7 (no agreement with statement = no recruitment barrier). Results: 38 of 55 recruiting physicians returned questionnaires (69% response rate), of which 35 could be analyzed (64% useable response rate). Recruiting physicians reported that "time constraints" (median agreement of 3, interquartile range 2-5) had the most negative impact on recruitment followed by "difficulties including identified eligible patients" (median agreement of 5, IQR 3-6). Other barriers such as "trial design barriers", "lack of access to treatment", "individual barriers of recruiting physicians" or "insufficient training of recruiting physicians" were perceived to have little or no impact on patient recruitment. Conclusion: Physicians perceived time constraints as the most relevant recruitment barrier in a randomized trial. To overcome recruitment barriers interventions, that are affordable for both industry- and investigator-driven trials, need to be developed and tested in randomized trials. Trial registration: ISRCTN84612310 [ABSTRACT FROM AUTHOR]

Background: Randomised trials comparing different drugs head-to-head are extremely valuable for clinical decision-making. However, it is scientifically and ethically sensible to demand strong evidence that a drug is effective by showing superiority over a placebo before embarking on head-to-head comparisons of potentially ineffective drugs. Our aim was to study the evolvement of evidence from placebo-controlled and head-to-head trials on the effects of antibiotics for the treatment of mild to moderate exacerbations of chronic obstructive pulmonary disease. Methods: We conducted a historical systematic review. Through electronic databases and hand-searches, we identified placebo-controlled and head-to-head antibiotic trials for the treatment of mild to moderate chronic obstructive pulmonary disease exacerbations. We compared the numbers of patients recruited in placebo-controlled and head-to-head trials between 1957 and 2005. Using cumulative meta-analysis of placebo-controlled trials, we determined when, if ever, placebo-controlled trials had shown convincing evidence that antibiotics are effective in preventing treatment failure in patients with mild to moderate chronic obstructive pulmonary disease exacerbations. Results: The first head-to-head trial was published in 1963. It was followed by another 100 trials comparing different antibiotics in a total of 34,029 patients with mild to moderate chronic obstructive pulmonary disease exacerbations. Over time, the cumulative odds ratio in placebo-controlled trials remained inconclusive throughout with odds ratios ranging from 0.39 (95% confidence intervals 0.04-4.22) to the most recent estimate (1995) of 0.81 (95% confidence intervals 0.52-1.28, P = 0.37). Conclusion: Placebo-controlled trials do not support the use of antibiotics in chronic obstructive pulmonary disease patients with mild to moderate exacerbations. Conducting head-to-head trials is, therefore, scientifically and ethically questionable. This underscores the requirement to perform or study systematic reviews of placebo-controlled trials before conducting head-to-head trials. [ABSTRACT FROM AUTHOR]

Background: Interpretation of the Hospital Anxiety and Depression Scale (HADS), commonly used to assess anxiety and depression in COPD patients, is unclear. Since its minimal important difference has never been established, our aim was to determine it using several approaches.Methods: 88 COPD patients with FEV1 /= 0.5 we performed linear regression analyses to predict the minimal important difference from the anchors. As distribution-based approach we used the Effect Size approach.Results: Based on CRQ emotional function and mastery domain as well as on total scores, the minimal important difference was 1.41 (95% CI 1.18-1.63) and 1.57 (1.37-1.76) for the HADS anxiety score and 1.68 (1.48-1.87) and 1.60 (1.38-1.82) for the HADS total score. Correlations of the HADS depression score and CRQ domain and Feeling Thermometer scores were < 0.5. Based on the Effect Size approach the MID of the HADS anxiety and depression score was 1.32 and 1.40, respectively.Conclusion: The minimal important difference of the HADS is around 1.5 in COPD patients corresponding to a change from baseline of around 20%. It can be used for the planning and interpretation of trials. [ABSTRACT FROM AUTHOR]

Background: Few epidemiologic studies have assessed health-related quality of life (HRQL) of asthma patients from a general population and it is unclear which instrument is best suitable for this purpose. We investigated the validity of the Asthma Quality of Life Questionnaire (AQLQ) and the SF-36 completed by individuals with asthma from the population-based SAPALDIA (Swiss study on air pollution and lung diseases in adults) cohort. Methods: The study included 258 participants with a physician-diagnosed asthma who had completed the AQLQ and SF-36. We assessed floor and ceiling effects, internal consistency reliability and cross-sectional validity with a priori hypotheses that correlations between the specific HRQL domains (e.g. "symptoms" or "physical functioning") and the corresponding external validation measures (respiratory symptoms, need for doctor visits, limitation in activities due to asthma and lung function) would capture similar aspects and be correlated moderately (≥ 0.3) to strongly (≥ 0.5), whereas non-corresponding domains be correlated weakly with each other (<0.3). Results: The AQLQ showed pronounced ceiling effects with all median domain scores above 6 (scores varied from 1-7). For the SF-36, ceiling effects were present in 5 out of 8 domains. Cronbach's alpha was >0.7 for all AQLQ and SF-36 domains. Correlations between the AQLQ domains "respiratory symptoms", "activity limitation" and "environmental exposure", and the validation measures ranged from 0.29-0.57. Correlations between the "emotional function" domain and the validation measures were also in this range (0.31-0.55) and not as low as we hypothesized. For the SF-36, correlations between "physical functioning" and "role physical", and the validation measures ranged from 0.25-0.56, whereas "role emotional" and "mental health" correlated with these measures from 0.01-0.23. Conclusion: The AQLQ and the SF-36 showed fairly good internal consistency. Both instruments are limited by ceiling effects, but they appear less pronounced in the SF-36, which also shows a better discrimination between different aspects of HRQL. The SF-36 may therefore be a more valid measure of HRQL than the AQLQ when applied to individuals with asthma from the general population. [ABSTRACT FROM AUTHOR]

Background: Evaluation of how Motor Imagery and conventional therapy (physiotherapy or occupational therapy) compare to conventional therapy only in their effects on clinically relevant outcomes during rehabilitation of persons with stroke. Design: Systematic review of the literature Methods: We conducted an electronic database search in seven databases in August 2005 and also hand-searched the bibliographies of studies that we selected for the review. Two reviewers independently screened and selected all randomized controlled trials that compare the effects of conventional therapy plus Motor Imagery to those of only conventional therapy on stroke patients. The outcome measurements were: Fugl-Meyer Stroke Assessment upper extremity score (66 points) and Action Research Arm Test upper extremity score (57 points). Due to the high variability in the outcomes, we could not pool the data statistically. Results: We identified four randomized controlled trials from Asia and North America. The quality of the included studies was poor to moderate. Two different Motor imagery techniques were used (three studies used audiotapes and one study had occupational therapists apply the intervention). Two studies found significant effects of Motor Imagery in the Fugl-Meyer Stroke Assessment: Differences between groups amounted to 11.0 (1.0 to 21.0) and 3.2 (-4 to 10.3) respectively and in the Action Research Arm Test 6.1 (-6.2 to 18.4) and 15.8 (0.5 to 31.0) respectively. One study did not find a significant effect in the Fugl-Meyer Stroke Assessment and Color trail Test (p = 0.28) but in the task-related outcomes (p > 0.001). Conclusion: Current evidence suggests that Motor imagery provides additional benefits to conventional physiotherapy or occupational therapy. However, larger and methodologically sounder studies should be conducted to assess the benefits of Motor imagery. [ABSTRACT FROM AUTHOR]

Background: For decades, there is an unresolved debate about adequate prescription of antibiotics for patients suffering from exacerbations of chronic obstructive pulmonary disease (COPD). The aim of this systematic review was to analyse randomised controlled trials investigating the clinical benefit of antibiotics for COPD exacerbations. Methods: We conducted a systematic review of randomised, placebo-controlled trials assessing the effects of antibiotics on clinically relevant outcomes in patients with an exacerbation. We searched bibliographic databases, scrutinized reference lists and conference proceedings and asked the pharmaceutical industry for unpublished data. We used fixed-effects models to pool results. The primary outcome was treatment failure of COPD exacerbation treatment. Results: We included 13 trials (1557 patients) of moderate to good quality. For the effects of antibiotics on treatment failure there was much heterogeneity across all trials (I2 = 82%). Metaregression revealed severity of exacerbation as significant explanation for this heterogeneity (p = 0.016): Antibiotics did not reduce treatment failures in outpatients with mild to moderate exacerbations (pooled odds ratio 1.09, 95% CI 0.75-1.59, I2 = 18%). Inpatients with severe exacerbations had a substantial benefit on treatment failure rates (pooled odds ratio of 0.25, 95% CI 0.16-0.39, I2 = 0%; number-needed to treat of 4, 95% CI 3-5) and on mortality (pooled odds ratio of 0.20, 95% CI 0.06-0.62, I2 = 0%; number-needed to treat of 14, 95% CI 12-30). Conclusion: Antibiotics effectively reduce treatment failure and mortality rates in COPD patients with severe exacerbations. For patients with mild to moderate exacerbations, antibiotics may not be generally indicated and further research is needed to guide antibiotic prescription in these patients. [ABSTRACT FROM AUTHOR]

Background: Experts defined a "minimum medical knowledge" (MMK) that people need for understanding typical signs and/or risk factors of four relevant clinical conditions: myocardial infarction, stroke, chronic obstructive pulmonary disease and HIV/AIDS. We tested to what degree Swiss adult citizens satisfy this criterion for MMK and whether people with medical experience have acquired better knowledge than those without. Methods: Questionnaire interview in a Swiss urban area with 185 Swiss citizens (median age 29 years, interquartile range 23 to 49, 52% male). We obtained context information on age, gender, highest educational level, (para)medical background and specific health experience with one of the conditions in the social surrounding. We calculated the proportion of MMK and examined whether citizens with medical background (personal or professional) would perform better compared to other groups. Results: No single citizen reached the full MMK (100%). The mean MMK was as low as 32% and the range was 0 -72%. Surprisingly, multivariable analysis showed that participants with a university degree (n = 84; β (95% CI) +3.7% MMK (0.4-7.1) p = 0.03), (para)medical background (n = 34; +6.2% MMK (2.0-10.4), p = 0.004) and personal illness experience (n = 96; +4.9% MMK (1.5-8.2), p = 0.004) had only a moderately higher MMK than those without, while age and sex had no effect on the level of MMK. Interaction between university degree and clinical experience (personal or professional) showed no effect suggesting that higher education lacks synergistic effect. Conclusion: This sample of Swiss citizens did not know more than a third of the MMK. We found little difference within groups with medical experience (personal or professional), suggesting that there is a consistent and dramatic lack of knowledge in the general public about the typical signs and risk factors of relevant clinical conditions. [ABSTRACT FROM AUTHOR]

Background: Combining outcomes and the use of standardized effect measures such as effect size and standardized response mean across instruments allows more comprehensive meta-analyses and should avoid selection bias. However, such analysis ideally requires that the instruments correlate strongly and that the underlying assumption of similar responsiveness is fulfilled. The aim of the study was to assess the correlation between two widely used health-related quality of life instruments for patients with chronic obstructive pulmonary disease and to compare the instruments' responsiveness on a study level. Methods: We systematically identified all longitudinal studies that used both the Chronic Respiratory Questionnaire (CRQ) and the St. George's Respiratory Questionnaire (SGRQ) through electronic searches of MEDLINE, EMBASE, CENTRAL and PubMed. We assessed the correlation between CRQ (scale 1 - 7) and SGRQ (scale 1 - 100) change scores and compared responsiveness of the two instruments by comparing standardized response means (change scores divided by their standard deviation). Results: We identified 15 studies with 23 patient groups. CRQ change scores ranged from -0.19 to 1.87 (median 0.35, IQR 0.14-0.68) and from -16.00 to 3.00 (median -3.00, IQR -4.73-0.25) for SGRQ change scores. The correlation between CRQ and SGRQ change scores was 0.88. Standardized response means of the CRQ (median 0.51, IQR 0.19-0.98) were significantly higher (p < 0.001) than for the SGRQ (median 0.26, IQR -0.03-0.40). Conclusion: Investigators should be cautious about pooling the results from different instruments in meta-analysis even if they appear to measure similar constructs. Despite high correlation in changes scores, responsiveness of instruments may differ substantially and could lead to important between-study heterogeneity and biased meta-analyses. [ABSTRACT FROM AUTHOR]

Background: Acute exacerbations of chronic obstructive pulmonary disease (COPD) represent a major burden for patients and health care systems. Respiratory rehabilitation may improve prognosis in these patients by addressing relevant risk factors for exacerbations such as low exercise capacity. To study whether respiratory rehabilitation after acute exacerbation improves prognosis and health status compared to usual care, we quantified its effects using meta-analyses. Methods: Systematic review of randomized controlled trials identified by searches in six electronic databases, contacts with experts, hand-searches of bibliographies of included studies and conference proceedings. We included randomized trials comparing the effect of respiratory rehabilitation and usual care on hospital admissions, health-related quality of life (HRQL), exercise capacity and mortality in COPD patients after acute exacerbation. Two reviewers independently selected relevant studies, extracted the data and evaluated the study quality. We pooled the results using fixed effects models where statistically significant heterogeneity (p = 0.1) was absent. Results: We identified six trials including 230 patients. Respiratory rehabilitation reduced the risk for hospital admissions (pooled relative risk 0.26 [0.12-0.54]) and mortality (0.45 [0.22-0.91]). Weighted mean differences on the Chronic Respiratory Questionnaire were 1.37 (95% CI 1.13-1.61) for the fatigue domain, 1.36 (0.94-1.77) for emotional function and 1.88 (1.67-2.09) for mastery. Weighted mean differences for the St. Georges Respiratory Questionnaire total score, impacts and activities domains were -11.1 (95% CI -17.1 to -5.2), -17.1 (95% CI -23.6 to -10.7) and -9.9 (95% CI -18.0 to -1.7). In all trials, rehabilitation improved exercise capacity (64-215 meters in six-minute walk tests and weighted mean difference for shuttle walk test 81 meter, 95% CI 48-115). Conclusion: Evidence from six trials suggests that respiratory rehabilitation is effective in COPD patients after acute exacerbation. Larger trials, however, are needed to further investigate the role of respiratory rehabilitation after acute exacerbation and its potential to reduce costs caused by COPD. [ABSTRACT FROM AUTHOR]

Background: Whether responsiveness represents a measurement property of health-related quality of life (HRQL) instruments that is distinct from reliability and validity is an issue of debate. We addressed the claims of a recent study, which suggested that investigators could rely on internal consistency to reflect instrument responsiveness. Methods: 516 patients with chronic obstructive pulmonary disease or knee injury participating in four longitudinal studies completed generic and disease-specific HRQL questionnaires before and after an intervention that impacted on HRQL. We used Pearson correlation coefficients and linear regression to assess the relationship between internal consistency reliability (expressed as Cronbach's alpha), instrument type (generic and disease-specific) and responsiveness (expressed as the standardised response mean, SRM). Results: Mean Cronbach's alpha was 0.83 (SD 0.08) and mean SRM was 0.59 (SD 0.33). The correlation between Cronbach's alpha and SRMs was 0.10 (95% CI -0.12 to 0.32) across all studies. Cronbach's alpha alone did not explain variability in SRMs (p = 0.59, r² = 0.01) whereas the type of instrument was a strong predictor of the SRM (p = 0.012, r2 = 0.37). In multivariable models applied to individual studies Cronbach's alpha consistently failed to predict SRMs (regression coefficients between -0.45 and 1.58, p-values between 0.15 and 0.98) whereas the type of instrument did predict SRMs (regression coefficients between -0.25 to -0.59, p-values between <0.01 and 0.05). Conclusion: Investigators must look to data other than internal consistency reliability to select a responsive instrument for use as an outcome in clinical trials. [ABSTRACT FROM AUTHOR]

Background: There is a controversy about the additional benefit of various supplemental interventions used in clinical practice to further enhance the effectiveness of respiratory rehabilitation in patients with Chronic obstructive pulmonary disease (COPD). The aim of this research was to assess randomised controlled trials (RCTs) testing the additional benefit of supplemental interventions during respiratory rehabilitation in COPD patients. Methods: Systematic review with literature searches in six electronic databases, extensive hand-searching and contacting of authors. Two reviewers selected independently eligible RCTs, rated the methodological quality and extracted the data, which were analyzed considering the minimal important difference of patient-important outcomes where possible. Findings: We identified 20 RCTs whereof 18 provided sufficient data for analysis. The methodological quality was low and sample sizes were too small for most trials to produce meaningful results (median total sample size = 28). Data from five trials showed that supplemental oxygen during exercise did not have clinically meaningful effects on health-related quality of life while improvements of exercise capacity may be even larger for patients exercising on room air. RCTs of adding assisted ventilation, nutritional supplements or a number of anabolically acting drugs do not provide sufficient evidence for or against the use any of these supplemental interventions. Interpretation: There is insufficient evidence for most supplemental interventions during respiratory rehabilitation to estimate their additional value, partly due to methodological shortcomings of included RCTs. Current data do not suggest benefit from supplemental oxygen during exercise, although the methodological quality of included trials limits conclusions. To appropriately assess any of the various supplemental interventions used in clinical practice, pragmatic trials on respiratory rehabilitation of COPD patients need to consider methodological aspects as well as appropriate sample sizes. [ABSTRACT FROM AUTHOR]