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A growing scientific literature highlights concern about the influence of social bias in medical care. Differential treatment of male and female patients has been among the documented concerns. Yet, little is known about the extent to which differential treatment of male and female patients reflects the influence of social bias or of more acceptable factors, such as different patient preferences or different anticipated outcomes of care. This paper attempts to ascertain the underlying basis for an observed differential in physicians' tendency to advise activity restrictions for male and female patients. We explore the extent to which the gender-based treatment differential is attributable to: (1) patients' health profile, (2) patients' role responsibilities, (3) patients' illness behaviors, and (4) physician characteristics. These four categories of variables correspond to four prominent social science hypotheses concerning gender differences in health and health care utilization (i.e. biological basis hypothesis, fixed role hypothesis, socialization hypothesis, physician bias hypothesis). Data are drawn from the Medical Outcomes Study (MOS), a longitudinal observational study of 1546 patients of 349 physicians practicing in three U.S. cities. Multivariate logistic regression is used to evaluate the likelihood of physician-prescribed activity restrictions for male and female patients, and to explore the absolute and relative influence of patient and physician factors on the observed treatment differential. Results reveal that the odds of prescribed activity restrictions are 3.6 times higher for female patients than for males with equivalent characteristics. The observed differential is not explained by differences in male and female patients' health or role responsibilities. Gender differences in illness behavior and physician gender biases both appear to contribute to the observed differential. Female patients exhibit more illness behavior than males, and these behaviors increase physicians' tendency to prescribe activity restrictions. After accounting for illness behavior differences and all other factors, the odds of prescribed activity restrictions among female patients of male physicians is four times that of equivalent male patients of those physicians. Medical practice, education, and research must strive to identify and remove the likely unconscious role of social bias in medical decision making. Key words - gender, illness behavior, physician-patient interaction

Elderly and poor people with chronic illnesses may do worse under a managed care plan than a fee-for-service plan. This was demonstrated in the Medical Outcomes Study, which has followed 2,235 people with chronic diseases for 4 years. Overall, most patients did just as well under an HMO as under a fee-for-service plan. However, the elderly and the poor fared worse under an HMO than a fee-for-service plan. Sixty-eight percent of those covered by an HMO experienced a decline in health compared to 27% of those in a fee-for-service plan., Objective.--To compare physical and mental health outcomes of chronically ill adults, including elderly and poor subgroups, treated in health maintenance organization (HMO) and fee-for-service (FFS) systems. Study Design.--A 4-year observational study of 2235 patients (18 to 97 years of age) with hypertension, non-insulin-dependent diabetes mellitus (NIDDM), recent acute myocardial infarction, congestive heart failure, and depressive disorder sampled from HMO and FFS systems in 1986 and followed up through 1990. Those aged 65 years and older covered under Medicare and low-income patients (200% of poverty) were analyzed separately. Setting and Participants.--Offices of physicians practicing family medicine, internal medicine, endocrinology, cardiology, and psychiatry, in HMO and FFS systems of care. Types of practices included both prepaid group (72% of patients) and independent practice association (28%) types of HMOs, large multispecialty groups, and solo or small, single-specialty practices in Boston, Mass, Chicago, III, and Los Angeles, Calif. Outcome MeasureS.--Differences between initial and 4-year follow-up scores of summary physical and mental health scales from the Medical Outcomes Study 36-1tern Short-Form Health Survey (SF-36) for all patients and practice settings. Results. On average, physical health declined and mental health remained stable during the 4-year follow-up period, with physical declines larger for the elderly than for the nonelderly (P Conclusions.--During the study period, elderly and poor chronically ill patients had worse physical health outcomes in HMOs than in FFS systems; mental health outcomes varied by study site and patient characteristics. Current health care plans should carefully monitor the health outcomes of these vulnerable subgroups. JAMA. 1996;276:1039-1047

We document the applicability of the SF-36 Health Survey, which was translated into Swedish using methods later adopted by the International Quality of Life Assessment (IQOLA) Project procedures. To test its appropriateness for use in Sweden, it was administered through mail-out/mail-back questionnaires in seven general population studies with an average response rate of 68%. The 8930 respondents varied by gender (48.2% men), age (range 15-93 years, mean age 42.7), marital status, education, socio-economic status, and geographical area. Psychometric methods used in the evaluation of the SF-36 in the U.S. were replicated. Over 90 % of respondents had complete items for each of the eight SF-36 scales, although more missing data were observed for subjects 75 years and over. Scale scores could be computed for the vast majority of respondents (95% and over); slightly fewer in the oldest subgroup. Item-internal consistency was consistently high across socio-demographic subgroups and the eight scales. Most reliability estimates exceeded the 0.80 level. The highest reliability was observed for the Bodily Pain Scale where all subgroups met the 0.90 level recommended for individual comparisons; coefficients at or above 0.90 were also observed in most subgroups for the Physical Functioning Scale. Tests of scaling assumptions including hypothesized item groupings, which reflect the construct validity of scales, were consistently favorable across subgroups, although lower rates were noted in the oldest age group. In conclusion, these studies have yielded empirical evidence supporting the feasibility of a non-English language reproduction of the SF-36 Health Survey. The Swedish SF-36 is ready for further evaluation. Key words - health status, SF-36 Health Survey, cross-cultural evaluation, psychometrics, validity, general population

Differences in the functioning and well-being of adult patients with current or past depressive disorder who visited clinicians of different specialties in health maintenance organizations, solo practices, or large multispecialty group practices were examined. For patients in different systems, there were no significant differences in functioning and well-being across 12 domains tested. Patients of mental health specialists had worse mental health and more limitations in social activities, whereas patients of medical clinicians had worse physical functioning, more pain, more physical/psychophysiologic symptoms, and worse health perceptions. Thus, each system of care had depressed patients with a similar functioning and well-being 'burden' but specialty sectors had patients with slightly different functioning and well-being profiles, probably reflecting patient selection of type of provider.

Patients of solo or single specialty (SOLO) practices who pay a fee for service (FFS) may be more satisfied with their care than those with other types of health care arrangements. Patients of health maintenance organizations (HMO) may be least satisfied with their care. Researchers examined satisfaction with an outpatient visit among 17,671 adults. These individuals were patients of SOLO practices, multispecialty groups (MSG) or HMOs with FFS or prepaid physician payment arrangements. Sixty-four percent of SOLO patients rated their visit as excellent, compared with 48% of the MSG patients and 49% of the HMO patients. SOLO and MSG patients who paid FFS were likely to be more satisfied with certain aspects of their visit than patients with prepaid physician payment arrangements., Objective.--To determine how patients in different kinds of practices--solo or single specialty (SOLO), multispecialty group (MSG), or health maintenance organizations (HMOs)--and with fee-for-service (FFS) or prepaid physician payment arrangements evaluate their medical care. Design.--Survey of adult outpatients after office visits, with sample weighted to represent population of patients visiting physicians in each practice type. Setting.--Offices of 367 internists, family practitioners, endocrinologists, cardiologists, and nurse practitioners, in HMOs (prepaid only), MSGs (prepaid and FFS), and SOLO practices (prepaid and FFS). Patients.--Adults (N=17671) at start of the Medical Outcomes Study. Outcome Measures.--Overall rating of the visit (five choices from excellent to poor). A random half of the sample also rated the provider's technical skills, personal manner, and explanations of care as well as time spent during the visit, the appointment wait, the office wait, the convenience of the office location, and telephone access. Results.--Fifty-five percent of patients rated their visit overall as excellent, 32% very good, 11% good, and 2% fair or poor. Patients of SOLO practitioners were more likely (64%) to rate their visit excellent than MSG (48$) or HMO (49%) patients (P

Treatment by specialists in solo or small single-speciality practices may be more expensive than treatment by general practitioners in health maintenance organizations. A survey of approximately 20,000 adult patients who visited a physician's office within different nine day periods, found that treatment by cardiologists and endocrinologists was more expensive than treatment by family practitioners and general internists. Patients treated by cardiologists and endocrinologists had more hospitalizations, tests and procedures, and took more prescription drugs than those treated by family practitioners and general internists. Patients treated by family practitioners tended to be younger and healthier with fewer chronic medical conditions than those treated by general internists, cardiologists and endocrinologists. Patients treated by solo or small single-speciality practices were hospitalized 41% more often than those treated by health maintenance organizations., Objective. - To examine whether specialty and system of care exert independent effects on resource utilization. Study Design. - Cross-sectional analysis of just over 20000 patients ([is greater than or equal to] 18 years of age) who visited providers' offices during 9-day periods in 1986. Patient-and physician-provided information was obtained by self-administered questionnaires. Setting. - Offices of 349 physicians practicing family medicine, internal medicine, endocrinology, and cardiology within health maintenance organizations, large multispecialty groups, and solo practices or small single-specialty group practices in three major US cities. Outcome Measures. - Indicators of the intensity of resource utilization were examined among four medical specialties (family practice, general internal medicine, cardiology, and endocrinology and five systems of care (health maintenance organization, multispecialty group-fee-for-service, multispecialty group-prepaid; solo practice and single-specialty group-fee-for-service, and solo practice and single-specialty group-prepaid before and after controlling for the mix of patients seen in these offices. The indicators of resource utilization were hospitalizations, annual office visits, prescription drugs, and common tests and procedures, with rates estimated on both a per-visit and per-year basis. Results. - Variation in patients mix was a major determinant of the large variations in resource use. However, increased utilization was also independently related to specialty (cardiology and endocrinology), fee-for-service payment plan, and solo and single-specialty group practice arrangements. After adjusting for patient mix, solo practice/single-specialty groups-fee-for-service had 41% more hospitalizations than health maintenance organizations. General internists had utilization rates somewhat greater than family physicians on some indicators. Conclusion. - Although variations in patients mix should be a major determinant of variations in resource use, the independent effects of specialty training, payment system, and practice organization on utilization rates need further explication. The 2- and 4- year outcomes now being analyzed will provide information critical to interpretation of the variations reported herein.

Patients who are older, sicker and have chronic medical conditions are more likely to be under the care of specialists in a solo or small single-specialty group practice than younger, healthier patients. A survey of 20,158 adults in three large cities who visited a physician's office during the study found that those with a chronic medical condition made more visits to physicians' offices, took more prescription drugs and were hospitalized more often than patients without a chronic medical condition. Patients treated by a family practitioner were younger and had better health with fewer chronic medical conditions, compared to patients treated by a specialist. Patients who visited a cardiologist were older with poorer health and more chronic medical conditions than those who visited a general internist. Patients treated by a solo practitioner were older and sicker with more chronic medical conditions than those who were treated at a health maintenance organization., Objective. - To determine differences in the mix of patients among medical specialties and among organizational systems of care. Study Design. - Cross-sectional analysis of 20 158 adults ([is greater than or equal to] 18 years of age who visited providers' offices during 9-day screening periods in 1986. Patient and physician information was obtained by self-administered, standardized questionnaires. Setting. - Offices of 349 physicians practicing family medicine, internal medicine, endocrinology, and cardiology within health maintenance organizations, large multispecialty groups, and solo or small single-specialty group practices in three major US cities. Outcome Measures. - Demographic characteristics, prevalence of chronic disease, disease-specific severity of illness, and functional status and well-being. Results. - Among patients with selected physician-reported chronic illnesses (diabetes, hypertension, recent myocardial infarction, or congestive heart failure), increasing levels of severity were associated with decreasing levels of functional status and well-being and with increased hospitalizations, more physician visits, and higher numbers of prescription drugs. Compared with patients of general internists, patients of cardiologists were older (56 vs 47 years, P

Objective: To evaluate validity and responsiveness of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in relation to other patient-reported outcome measures before and after total knee replacement (TKR).Methods: Pre-TKR and 6-month post-TKR data from 1,143 patients in a US joint replacement cohort were used to compare the KOOS, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the SF-36 Health Survey (SF-36). Validity was evaluated with multiple methods, including correlations of pre-TKR scale scores and analysis of variance models that used pre-TKR data to compare the relative validity of scales in discriminating between groups differing in assistive walking device use and number of comorbid conditions. Validity was also evaluated by using post-TKR minus pre-TKR change scores to assess relative validity of scales in discriminating between groups rating themselves as better, same, or worse (BSW) in their capability to do activities at 6 months. Responsiveness also was described using effect sizes and standardized response means.Results: In support of convergent and discriminant validity, KOOS scale scores were worse for patients using an assistive device but only declined weakly with increasing comorbid conditions. While all knee-specific scales discriminated between BSW groups, the KOOS quality of life (QOL) scale was significantly better (P < 0.05) than all measures except the SF-36 physical component summary. KOOS QOL also had the highest effect size, while SF-36 measures had lower effect sizes and standardized response means. KOOS pain and symptoms scales discriminated better than WOMAC pain and stiffness scales among BSW groups.Conclusion: KOOS scales were valid and responsive in this cohort of US TKR patients. KOOS QOL performed particularly well in capturing aggregate knee-specific outcomes. [ABSTRACT FROM AUTHOR]

This study examined the awareness of clinicians to detect depression in 650 patients with depressive disorders. Clinicians were from various types of health care settings, including single specialty medical practices with one or more clinicians, large multispecialty group practices, and a health maintenance organization operating in three states. The detection of depression did not differ among the various types of health care settings. Depression was diagnosed in 78 to 87 percent of the patients who visited mental health specialists, but only in 46 to 51 percent of the patients who visited medical clinicians. The type of payment for medical care did not affect whether depression was detected in patients who were examined by mental health specialists. However, among patients visiting medical clinicians, depression was less likely to be diagnosed if care was financed by prepayment systems as compared to fee-for-service programs. The results are consistent with previous findings that mental health care in prepaid plans is less intense than mental health care in fee-for-service programs. These and other findings can contribute to the improvement of health care systems and costs., ABSTRACT: We estimated clinicians&apos; awareness of depression for patients with current depressive disorder (N = 650) who received care in either a single-specialty solo or small group practice, a large multispecialty group practice, or a health maintenance organization in three US sites. Depressive disorder was determined by independent diagnostic assessment shortly after an office visit. Detection and treatment of depression were determined from visit-report forms completed by the treating clinician. Depending on the setting, from 78.2% to 86.9% of depressed patients who visited mental health specialists had their depression detected at the time of the visit, compared with 45.9% to 51.2% of depressed patients who visited medical clinicians, after adjusting for case-mix differences. Among patients of mental health specialists, there were no significant differences by type of payment in the likelihood of depressive disorder being detected or treated. Among patients of medical clinicians, however, those receiving care financed by prepayment were significantly less likely to have their depression detected or treated during the visit than were similar patients receiving fee-for-service care.

Background: To document the development and evaluation of the Quality of life Disease Impact Scale (QDIS®), a measure that standardizes item content and scoring across chronic conditions and provides a summary, norm-based QOL impact score for each disease.Methods: A bank of 49 disease impact items was constructed from previously-used descriptions of health impact to represent ten frequently-measured quality of life (QOL) content areas and operational definitions successfully utilized in generic QOL surveys. In contrast to health in general, all items were administered with attribution to a specific disease (osteoarthritis, rheumatoid arthritis, angina, myocardial infarction, congestive heart failure, chronic kidney disease (CKD), diabetes, asthma, or COPD). Responses from 5418 adults were analyzed as five disease groups: arthritis, cardiovascular, CKD, diabetes, and respiratory. Unidimensionality, item parameter and scale-level invariance, reliability, validity and responsiveness to change during 9-month follow-up were evaluated by disease group and for all groups combined using multi-group confirmatory factor analysis (MGCFA), item response theory (IRT) and analysis of variance methods. QDIS was normed in an independent chronically ill US population sample (N = 4120).Results: MGCFA confirmed a 1-factor model, justifying a summary score estimated using equal parameters for each item across disease groups. In support of standardized IRT-based scoring, correlations were very high between disease-specific and standardized IRT item slopes (r = 0.88-0.96), thresholds (r = 0.93-0.99) and person-level scores (r ≥ 0.99). Internal consistency, test-retest and person-level IRT reliability were consistently satisfactory across groups. In support of interpreting QDIS as a disease-specific measure, in comparison with generic measures, QDIS consistently discriminated markedly better across disease severity levels, correlated higher with other disease-specific measures in cross-sectional tests, and was more responsive in comparisons of groups with better, same or worse evaluations of disease-specific outcomes at the 9-month follow-up.Conclusions: Standardization of content and scoring across diseases was shown to be justified psychometrically and enabled the first summary measure of disease-specific QOL impact normed in the chronically ill population. This disease-specific approach substantially improves discriminant validity and responsiveness over generic measures and provides a basis for better understanding the relative QOL impact of multiple chronic conditions in research and clinical practice. [ABSTRACT FROM AUTHOR]

Background: Assessment of health-related quality of life (HRQoL) is well established in clinical research, but ceiling effects in validated tools might prevent detection of changes in well respondents. Tobacco Quality of Life Impact Tool (TQOLITv1) uses conceptual and psychometric advances to enhance detection of HRQoL changes.Methods: In a 6-month, forced-switch study, the German TQOLITv1 was assessed in healthy adult (age 23-55 years) current and matched former-smokers. At baseline, smokers were switched to reduced toxicant prototype (RTP) or conventional cigarette for 6 months. TQOLITv1 responses were collected at baseline, 3 and 6 months from current smokers whilst former smokers completed it at the latter two time points. TQOLITv1 includes SF-36v2 and new smoking-specific, physical and general-health measures.Results: Reliability at baseline was good (Cronbach's coefficient alpha > 0.70) for all measures. The baseline percentage with the best possible score (ceiling effect) for former and current smokers was substantially better for the new physical function than SF-36 physical function measure (35% vs. 59% at ceiling, respectively). New smoking-specific measures discriminated current from former smokers better than general health measures. Smoking-specific symptoms (r = 0.73) were more stable from baseline to 6 months than other measures (r = 0.38-0.54) particularly more than the SF-36 mental component score (r = 0.24). Although both product smoking groups worsened in most HRQoL measures, changes in general and smoking-specific HRQoL impact measures favored RTP smokers.Conclusions: The German TQOLITv1 is sufficiently reliable and valid to assess HRQoL and may be more useful than SF-36v2 in evaluation of interventions in well smoking populations including those consuming RTPs. [ABSTRACT FROM AUTHOR]

Background: The Prostate Cancer Prevention Trial (PCPT)-a randomized placebo-controlled study of the efficacy of finasteride in preventing prostate cancer-offered the opportunity to prospectively study effects of finasteride and other covariates on the health-related quality of life of participants in a multiyear trial.Methods: We assessed three health-related quality-of-life domains (measured with the Health Survey Short Form-36: Physical Functioning, Mental Health, and Vitality scales) via questionnaires completed by PCPT participants at enrollment (3 months before randomization), at 6 months after randomization, and annually for 7 years. Covariate data obtained at enrollment from patient-completed questionnaires were included in our model. Mixed-effects model analyses and a cross-sectional presentation at three time points began at 6 months after randomization. All statistical tests were two-sided.Results: For the physical function outcome (n = 16 077), neither the finasteride main effect nor the finasteride interaction with time were statistically significant. The effects of finasteride on physical function were minor and accounted for less than a 1-point difference over time in Physical Functioning scores (mixed-effect estimate = 0.07, 95% confidence interval [CI] = -0.28 to 0.42, P = .71). Comorbidities such as congestive heart failure (estimate = -5.64, 95% CI = -7.96 to -3.32, P < .001), leg pain (estimate = -2.57, 95% CI = -3.04 to -2.10, P < .001), and diabetes (estimate = -1.31, 95% CI = -2.04 to -0.57, P < .001) had statistically significant negative effects on physical function, as did current smoking (estimate = -2.34, 95% CI = -2.97 to -1.71, P < .001) and time on study (estimate = -1.20, 95% CI = -1.36 to -1.03, P < .001). Finasteride did not have a statistically significant effect on the other two dependent variables, mental health and vitality, either in the mixed-effects analyses or in the cross-sectional analysis at any of the three time points.Conclusion: Finasteride did not negatively affect SF-36 Physical Functioning, Mental Health, or Vitality scores. [ABSTRACT FROM AUTHOR]

Objective: To quantify the total and unique burden of Restless Legs Syndrome (RLS) on patient-reported health-related quality of life (HRQoL).Methods: The disease burden that RLS places on HRQoL was estimated by comparing Short-Form (SF-36) scores between individuals with RLS and several patient and general populations in the US. Regression methods were applied to estimate SF-36 normative values from the general population sample and statistically adjust them to match age, gender and disease comorbidity characteristics of the RLS sample. Significance tests were then used to compare the means across samples.Results: All SF-36 measures were significantly below adjusted US general population norms. Five of the eight scales (physical functioning, role physical, bodily pain, general health, vitality) were below US norms by 0.8 or more standard deviations (SD), while the remaining three (social functioning, role emotional, mental health) were 0.5 SD below norm. The burden of RLS was greater on physical than on mental/emotional HRQoL (physical and mental summary scores were 1.08 and 0.40 SD below norm, respectively), and greater than that observed for type-2 diabetes.Conclusion: After controlling for the impact of age, gender, and disease comorbidity, RLS was associated with unique burden on both physical and mental aspects of HRQoL. [ABSTRACT FROM AUTHOR]

Objective: To compare the measurement properties of the Modified Health Assessment Questionnaire [MHAQ], the SF-36((R)) Health Survey 10 item Physical Functioning scale [PF10], and scores from an item response theory (IRT) based scale combining the two measures.Study Design: Rheumatoid arthritis (RA) patients (n = 339) enrolled in a multi-center, randomized, double-blind, placebo-controlled trial completed the MHAQ and the SF-36 pre- and post-treatment. Psychometric analyses used confirmatory factor analysis and IRT models. Analyses of variance were used to assess sensitivity to changes in disease severity (defined by the American College of Rheumatism (ACR)) using change scores in MHAQ, PF10, and IRT scales. Analyses of covariance were used to assess treatment responsiveness.Results: For the entire score range, the 95% confidence interval around individual patient scores was smaller for the combined (total) IRT based scale than for other measures. The MHAQ and PF10 were about 70% and 50% as efficient as the total IRT score of physical functioning in discriminating among ACR groups, respectively. The MHAQ and PF10 were also less efficient than the total IRT score in discriminating among treatment groups.Conclusions: Combining scales from the two short forms yields a more powerful tool with greater sensitivity to treatment response. [ABSTRACT FROM AUTHOR]

Context: Few studies and no international comparisons have examined the impact of multiple chronic conditions on populations using a comprehensive health-related quality of life (HRQL) questionnaire.Objective: The impact of common chronic conditions on HRQL among the general populations of eight countries was assessed.Design: Cross-sectional mail and interview surveys were conducted.Participants and Setting: Sample representatives of the adult general population of eight countries (Denmark, France, Germany, Italy, Japan, The Netherlands, Norway and the United States) were evaluated. Sample sizes ranged from 2031 to 4084.Main Outcome Measures: Self-reported prevalence of chronic conditions (including allergies, arthritis, congestive heart failure, chronic lung disease, hypertension, diabetes, and ischemic heart disease), sociodemographic data and the SF-36 Health Survey were obtained. The SF-36 scale and summary scores were estimated for individuals with and without selected chronic conditions and compared across countries using multivariate linear regression analyses. Adjustments were made for age, gender, marital status, education and the mode of SF-36 administration.Results: More than half (55.1%) of the pooled sample reported at least one chronic condition, and 30.2% had more than one. Hypertension, allergies and arthritis were the most frequently reported conditions. The effect of ischemic heart disease on many of the physical health scales was noteworthy, as was the impact of diabetes on general health, or arthritis on bodily pain scale scores. Arthritis, chronic lung disease and congestive heart failure were the conditions with a higher impact on SF-36 physical summary score, whereas for hypertension and allergies, HRQL impact was low (comparing with a typical person without chronic conditions, deviation scores were around -4 points for the first group and -1 for the second). Differences between chronic conditions in terms of their impact on SF-36 mental summary score were low (deviation scores ranged between -1 and -2).Conclusions: Arthritis has the highest HRQL impact in the general population of the countries studied due to the combination of a high deviation score on physical scales and a high frequency. Impact of chronic conditions on HRQL was similar roughly across countries, despite important variation in prevalence. The use of HRQL measures such as the SF-36 should be useful to better characterize the global burden of disease. [ABSTRACT FROM AUTHOR]

Background: Item response theory (IRT) is a powerful framework for analyzing multiitem scales and is central to the implementation of computerized adaptive testing.Objectives: To explain the use of IRT to examine measurement properties and to apply IRT to a questionnaire for measuring migraine impact--the Migraine Specific Questionnaire (MSQ).Methods: Data from three clinical studies that employed the MSQ-version 1 were analyzed by confirmatory factor analysis for categorical data and by IRT modeling.Results: Confirmatory factor analyses showed very high correlations between the factors hypothesized by the original test constructions. Further, high item loadings on one common factor suggest that migraine impact may be adequately assessed by only one score. IRT analyses of the MSQ were feasible and provided several suggestions as to how to improve the items and in particular the response choices. Out of 15 items, 13 showed adequate fit to the IRT model. In general, IRT scores were strongly associated with the scores proposed by the original test developers and with the total item sum score. Analysis of response consistency showed that more than 90% of the patients answered consistently according to a unidimensional IRT model. For the remaining patients, scores on the dimension of emotional function were less strongly related to the overall IRT scores that mainly reflected role limitations. Such response patterns can be detected easily using response consistency indices. Analysis of test precision across score levels revealed that the MSQ was most precise at one standard deviation worse than the mean impact level for migraine patients that are not in treatment. Thus, gains in test precision can be achieved by developing items aimed at less severe levels of migraine impact.Conclusions: IRT proved useful for analyzing the MSQ. The approach warrants further testing in a more comprehensive item pool for headache impact that would enable computerized adaptive testing. [ABSTRACT FROM AUTHOR]

Background: Measurement of headache impact is important in clinical trials, case detection, and the clinical monitoring of patients. Computerized adaptive testing (CAT) of headache impact has potential advantages over traditional fixed-length tests in terms of precision, relevance, real-time quality control and flexibility.Objective: To develop an item pool that can be used for a computerized adaptive test of headache impact.Methods: We analyzed responses to four well-known tests of headache impact from a population-based sample of recent headache sufferers (n = 1016). We used confirmatory factor analysis for categorical data and analyses based on item response theory (IRT).Results: In factor analyses, we found very high correlations between the factors hypothesized by the original test constructers, both within and between the original questionnaires. These results suggest that a single score of headache impact is sufficient. We established a pool of 47 items which fitted the generalized partial credit IRT model. By simulating a computerized adaptive health test we showed that an adaptive test of only five items had a very high concordance with the score based on all items and that different worst-case item selection scenarios did not lead to bias.Conclusion: We have established a headache impact item pool that can be used in CAT of headache impact. [ABSTRACT FROM AUTHOR]

Objective : To evaluate the feasibility of computerized adaptive testing (CAT) and the reliability and validity of CAT-based estimates of headache impact scores in comparison with ‘static’ surveys. Methods : Responses to the 54-item Headache Impact Test (HIT) were re-analyzed for recent headache sufferers (n = 1016) who completed telephone interviews during the National Survey of Headache Impact (NSHI). Item response theory (IRT) calibrations and the computerized dynamic health assessment (DYNHA[sup ®] ) software were used to simulate CAT assessments by selecting the most informative items for each person and estimating impact scores according to pre-set precision standards (CAT-HIT). Results were compared with IRT estimates based on all items (total-HIT), computerized 6-item dynamic estimates (CAT-HIT-6), and a developmental version of a ‘static’ 6-item form (HIT-6-D). Analyses focused on: respondent burden (survey length and administration time), score distributions (‘ceiling’ and ‘floor’ effects), reliability and standard errors, and clinical validity (diagnosis, level of severity). A random sample (n = 245) was re-assessed to test responsiveness. A second study (n = 1103) compared actual CAT surveys and an improved ‘static’ HIT-6 among current headache sufferers sampled on the Internet. Respondents completed measures from the first study and the generic SF-8™ Health Survey; some (n = 540) were re-tested on the Internet after 2 weeks. Results : In the first study, simulated CAT-HIT and total-HIT scores were highly correlated (r = 0.92) without ‘ceiling’ or ‘floor’ effects and with a substantial reduction (90.8%) in respondent burden. Six of the 54 items accounted for the great majority of item administrations (3603/5028, 77.6%). CAT-HIT reliability estimates were very high (0.975–0.992) in the range where 95% of respondents scored, and relative validity (RV) coefficients were high for diagnosis (RV = 0.87) and severity (RV = 0.89); patient-level classifications were accurate 91.3% for a diagnosis of migraine. For all three criteria of change, CAT-HIT scores were more responsive than all other measures. In the second study, estimates of respondent burden, item usage, reliability and clinical validity were replicated. The test–retest reliability of CAT-HIT was 0.79 and alternate forms coefficients ranged from 0.85 to 0.91. All correlations with the generic SF-8 were negative. Conclusions : CAT-based administrations of headache impact items achieved very large reductions in respondent burden without compromising validity for purposes of patient screening or monitoring changes in headache impact over time. IRT models and CAT-based dynamic health assessments warrant testing among patients with other conditions. [ABSTRACT FROM AUTHOR]

Background: Item response theory (IRT) scoring of health status questionnaires offers many advantages. However, to ensure 'backwards comparability' and to facilitate interpretations of results, we need the ability to express the IRT score in the metrics of the traditional scales.Objectives: To develop procedures to calibrate IRT-based scores on the Headache Impact Test (HIT) into the metrics of the traditional headache scales. To assess the degree to which the calibrated HIT scores agree with the observed traditional scores and lead to the same conclusions in group comparisons.Methods: We used telephone interview data (n = 1016) and Internet data (n = 1103) from general population surveys of recent headache sufferers. Analyses were conducted in four steps: (1) develop IRT models for all items, (2) for each IRT score level, calculate the expected score on each of the traditional scales (calibration), (3) adjust this calibrated score for measurement error in the IRT score, (4) for each of the traditional scales, assess agreement between calibrated HIT scores and observed scores using intraclass correlation (ICC) and evaluate the agreement of mean scores and the relative validity (RV) in discriminating among groups differing in migraine diagnosis, headache severity, and change in impact over time.Results: For the traditional categorical questionnaire items (the Migraine Specific Questionnaire (MSQ) and the Headache Disability Inventory (HDI)) the calibrated HIT agreed with the observed traditional scores: ICC's were between 0.80 and 0.94. In RV analyses the maximum mean difference between the observed and expected scores was 1.7 points on a 0-100 scale for comparisons at one point in time. Analyses of change over time and analyses calibrating scores from the fixed-form HIT-6 to the metric of other questionnaires were also satisfactory although less precise. Analysis of non-standard questionnaire items (e.g. On how many days in the past 3 months did you have a headache, from the HIMQ and the MIDAS) required special IRT models. Agreement was less good: ICC's were between 0.56 and 0.61 and the maximum mean differences were 2.9 (on a 0-270 scale) and 3.8 (on a 0-450 scale) in RV analyses at one point in time. The ability of the calibrated scale scores to discriminate between groups was at least as good as the ability of the observed sum scales and often remarkably better.Conclusion: The theoretical advantage of IRT models in scale calibration is supported by our results. This approach to achieving comparability of new and widely-used scales and accelerating the accumulation of interpretation guidelines based on previous work warrant testing for measures of other generic and disease-specific concepts. [ABSTRACT FROM AUTHOR]

Background: Migraine headaches have been shown to have substantial personal and societal implications. Health-related quality of life (HRQOL) assessments of migraineurs have been used to monitor and evaluate patient- and population-based outcomes, and to evaluate effectiveness and responsiveness to treatment. In this paper, we test a new, even shorter generic health survey, the SF-8 Health Survey (SF-8), an alternate form that uses one question to measure each of the eight SF-36 Health Survey (SF-36) domains, in a sub-sample of migraine sufferers.Methods: Data from 7557 participants surveyed via the Internet and mail were used to document the burden of migraine on HRQOL and to compare the relative burden of migraine with other chronic conditions using the SF-8.Results: Migraineurs' HRQOL is similar to those with congestive heart failure, hypertension and diabetes, and is better than those with depression. Migraine sufferers experience better physical health and worse mental health (MH) than those with osteoarthritis. Results support prior research indicating that the burden of migraine on functional health and well-being is considerable and comparable to other chronic conditions known to have substantial impact on HRQOL.Conclusions: The SF-8 may provide a more practical and efficient method to describe the burden of migraine in population studies. [ABSTRACT FROM AUTHOR]

Analyses of cognitive aspects of survey methodology (CASM) and psychometric analysis are two methods that are able to complement each other. We use concrete examples to illustrate how psychometric analyses can test hypotheses from CASM. The psychometrics framework recognizes that survey responses are affected by other factors than the concept being assessed, for example by cognitive factors and processes. Such factors are subsumed under the concept of measurement error. Possible sources of measurement error can be tested, e.g. by randomized experiments. A standard way to reduce measurement error is to ask several questions about the same concept and combine the answers into a multi-item scale that is more precise than the individual items. Techniques like structural equation models use the item correlations to assess the magnitude of measurement error and to test the assumptions behind the multi-item scale, e.g. the effect of common response choices and item time frames. A central problem in modern psychometrics is how to model the mapping of the continuous latent variable onto the item response choice categories. This is achieved by threshold models (e.g. item response models and structural equation models for categorical data). These models can, for example, analyze the impact of mode of administration, test whether the items function in the same way for all people (measurement invariance/differential item functioning) and examine the consistency of responses from any single person. Such analyses provide new possibilities for combining psychometrics and cognitive methods. [ABSTRACT FROM AUTHOR]

Objective: To evaluate reliability, validity and responsiveness of KOOS-12, a 12-item short form of the 42-item Knee injury and Osteoarthritis Outcome Score (KOOS) that provides Pain, Function and Quality of Life (QOL) scale scores and a summary knee impact score.Design: Data from 1,392 knee osteoarthritis (OA) patients from the FORCE-TJR research cohort who completed KOOS before and 6 and 12 months after total knee replacement (TKR) were analyzed. KOOS-12 includes a pain frequency item and three items measuring pain during increasingly difficult (sitting/lying, walking, stairs) activities; function items about standing, rising from sitting, getting in/out of a car, and twisting/pivoting; and the 4-item KOOS QOL scale. Percent computable scale scores, floor and ceiling effects, internal consistency reliability, validity (scale correlations, tests of known groups validity using one-way analysis of variance (ANOVA)) and responsiveness (effect sizes, standardized response means) were compared for the KOOS-12, full-length KOOS, KOOS-PS and KOOS, JR.Results: Internal consistency reliability was above 0.70 for all KOOS-12 scales and ≥0.90 for the KOOS-12 Summary score. Validity and responsiveness of KOOS-12 Pain, Function and QOL scales was satisfactory and reached similar conclusions as comparable full-length KOOS scales. The KOOS-12 Summary score was most responsive in discriminating between groups who differed in global ratings of post-TKR change in physical capabilities and had the highest effect sizes and standardized response means.Conclusions: KOOS-12 was a reliable and valid alternative to KOOS in TKR patients with moderate to severe OA and provided three domain-specific and summary knee impact scores with substantially reduced respondent burden. [ABSTRACT FROM AUTHOR]

Background: Health-related quality of life (QOL) surveys include generic measures that enable comparisons across conditions and measures that focus more specifically on one disease or condition. We evaluated the psychometric properties of German- and English-language versions of survey scales representing both types of measures in samples of current and former smokers.Methods: TQOLIT(™)v1 integrates new measures of smoking-specific symptoms and QOL impact attributed to smoking with generic SF-36 Health Survey measures. For purposes of evaluation, cross-sectional data were analyzed for two independent samples. Disease-free (otherwise healthy) adults ages 23-55 used a tablet to complete surveys in a clinical trial in Germany (125 current and 54 former smokers). Online general population surveys were completed in the US by otherwise healthy current and former smokers (N = 149 and 110, respectively). Evaluations included psychometric tests of assumptions underlying scale construction and scoring, score distributions, and reliability. Tests of validity included cross-sectional correlations and analyses of variance based on a conceptual framework and hypotheses for groups differing in self-reported smoking behavior (current versus former smoker, cigarettes per day (CPD)) and severity of smoking symptoms in both samples and, in the German trial only, clinical parameters of biomarkers of exposure.Results: Tests of scaling assumptions and internal consistency reliability (alpha = 0.71-0.79) of the smoking-specific measures were satisfactory, although ceiling effects attenuated correlations for former smokers in both samples. Correlational evidence supporting validity of smoking-specific symptom and impact measures included their substantial inter-correlation and higher correlations (than generic measures) with smoking behavior (favoring former over current groups) and CPD in both samples. In the German trial, both smoking-specific measures correlated significantly (p < 0.05) with all four biomarkers. QOL impact attributed to smoking correlated with the SF-36 mental but not physical summary measures in both samples.Conclusions: German- and English-language TQOLITv1 surveys have comparable and satisfactory psychometric properties. Cross-sectional tests, including correlations with four biomarkers, support the validity of the new smoking-specific measures for use in studies of otherwise healthy smokers. Smoking-specific measures consistently performed better than generic QOL measures in all tests of validity. [ABSTRACT FROM AUTHOR]

Background: Relative validity (RV), a ratio of ANOVA F-statistics, is often used to compare the validity of patient-reported outcome (PRO) measures. We used the bootstrap to establish the statistical significance of the RV and to identify key factors affecting its significance.Methods: Based on responses from 453 chronic kidney disease (CKD) patients to 16 CKD-specific and generic PRO measures, RVs were computed to determine how well each measure discriminated across clinically-defined groups of patients compared to the most discriminating (reference) measure. Statistical significance of RV was quantified by the 95% bootstrap confidence interval. Simulations examined the effects of sample size, denominator F-statistic, correlation between comparator and reference measures, and number of bootstrap replicates.Results: The statistical significance of the RV increased as the magnitude of denominator F-statistic increased or as the correlation between comparator and reference measures increased. A denominator F-statistic of 57 conveyed sufficient power (80%) to detect an RV of 0.6 for two measures correlated at r = 0.7. Larger denominator F-statistics or higher correlations provided greater power. Larger sample size with a fixed denominator F-statistic or more bootstrap replicates (beyond 500) had minimal impact.Conclusions: The bootstrap is valuable for establishing the statistical significance of RV estimates. A reasonably large denominator F-statistic (F > 57) is required for adequate power when using the RV to compare the validity of measures with small or moderate correlations (r < 0.7). Substantially greater power can be achieved when comparing measures of a very high correlation (r > 0.9). [ABSTRACT FROM AUTHOR]