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Abstract Objective This study investigated the associations between the number of authors and collective self-citations versus citations by others. Study design and setting We analyzed 88,594 health science articles published in 2015 and citations they received until 2020. The main variables were the number of authors, the number of citations by co-authors (collective self-citations), and the number of citations by others. Results The number of authors correlated more strongly with the number of citations by co-authors than with citations by others (Spearman r 0.31 vs. 0.23; mutually adjusted r 0.26 vs. 0.12). The percentage of self-citations among all citations was 10.6% for single-authored articles, and increased gradually with the number of authors to 34.8% for ≥ 50 authors. Collective self-citations increased the proportion of articles reaching or exceeding 30 total citations by 0.7% for single-authored articles, but by 11.6% for articles written by ≥ 50 authors. Conclusions If citations by others reflect scientific utility, then another mechanism must explain the excess of collective self-citations observed for multi-authored articles. The results support the hypothesis that the authors’ own motivations explain this excess. The evaluation of scientific utility should also be based on citations by others, excluding collective self-citations.

Abstract Background Scientific productivity is often evaluated by means of cumulative citation metrics. Different metrics produce different incentives. The H-index assigns full credit from a citation to each coauthor, and thus may encourage multiple collaborations in mid-list author roles. In contrast, the Hm-index assigns only a fraction 1/k of citation credit to each of k coauthors of an article, and thus may encourage research done by smaller teams, and in first or last author roles. Whether H and Hm indices are influenced by different authorship patterns has not been examined. Methods Using a publicly available Scopus database, I examined associations between the numbers of research articles published as single, first, mid-list, or last author between 1990 and 2019, and the H-index and the Hm-index, among 18,231 leading researchers in the health sciences. Results Adjusting for career duration and other article types, the H-index was negatively associated with the number of single author articles (partial Pearson r -0.06) and first author articles (-0.08), but positively associated with the number of mid-list (0.64) and last author articles (0.21). In contrast, all associations were positive for the Hm-index (0.04 for single author articles, 0.18 for first author articles, 0.24 for mid-list articles, and 0.46 for last author articles). Conclusion The H-index and the Hm-index do not reflect the same authorship patterns: the full-credit H-index is predominantly associated with mid-list authorship, whereas the partial-credit Hm-index is driven by more balanced publication patterns, and is most strongly associated with last-author articles. Since performance metrics may act as incentives, the selection of a citation metric should receive careful consideration.

Abstract Background Adjustment for baseline prognostic factors in randomized clinical trials is usually performed by means of sample-based regression models. Sample-based models may be incorrect due to overfitting. To assess whether overfitting is a problem in practice, we used simulated data to examine the performance of the sample-based model in comparison to a “true” adjustment model, in terms of estimation of the treatment effect. Methods We conducted a simulation study using samples drawn from a “population” in which both the treatment effect and the effect of the potential confounder were specified. The outcome variable was binary. Using logistic regression, we compared three estimates of the treatment effect in each situation: unadjusted, adjusted for the confounder using the sample, adjusted for the confounder using the true effect. Experimental factors were sample size (from 2 × 50 to 2 × 1000), treatment effect (logit of 0, 0.5, or 1.0), confounder type (continuous or binary), and confounder effect (logit of 0, − 0.5, or − 1.0). The assessment criteria for the estimated treatment effect were bias, variance, precision (proportion of estimates within 0.1 logit units), type 1 error, and power. Results Sample-based adjustment models yielded more biased estimates of the treatment effect than adjustment models that used the true confounder effect but had similar variance, accuracy, power, and type 1 error rates. The simulation also confirmed the conservative bias of unadjusted analyses due to the non-collapsibility of the odds ratio, the smaller variance of unadjusted estimates, and the bias of the odds ratio away from the null hypothesis in small datasets. Conclusions Sample-based adjustment yields similar results to exact adjustment in estimating the treatment effect. Sample-based adjustment is preferable to no adjustment.

Abstract Background We assessed potential consent bias in a cohort of > 40,000 adult patients asked by mail after hospitalization to consent to the use of past, present and future clinical and biological data in an ongoing ‘general consent’ program at a large tertiary hospital in Switzerland. Methods In this retrospective cohort study, all adult patients hospitalized between April 2019 and March 2020 were invited to participate to the general consent program. Demographic and clinical characteristics were extracted from patients’ electronic health records (EHR). Data of those who provided written consent (signatories) and non-responders were compared and analyzed with R studio. Results Of 44,819 patients approached, 10,299 (23%) signed the form. Signatories were older (median age 54 [IQR 38–72] vs. 44 years [IQR 32–60], p

Objective To determine the proportion of children in low-income and lower-middle-income countries exposed to intimate partner violence (IPV).Design Systematic review.Data sources PubMed, CINAHL, ERIC, PsycINFO, Web of Science, WHO Global Index Medicus, and Violence and Abuse Abstracts, hand searching of specialised journals from inception until 19 May 2019.Eligibility criteria for selecting studies Primary quantitative studies that included a measure of self-reported exposure to IPV prior to age 18 and were conducted in low-income and lower-middle-income countries.Data extraction and synthesis Data were screened, extracted and appraised by two independent reviewers. The prevalence estimates were pooled using a random-effects model. Outcomes included lifetime and past-year prevalence of childhood exposure to IPV. Meta-regression was used to explore heterogeneity. Publication bias was assessed using a funnel plot and Egger’s regression test. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.Results Sixty-two studies with a total of 231 512 participants were included. Eighty-five lifetime prevalence estimates and 6 estimates of past-year prevalence were available for synthesis. The average lifetime prevalence of childhood exposure to IPV was 29% (95% CI 26% to 31%). The average past-year prevalence in children was 35% (95% CI 21% to 48%). The lifetime prevalence disaggregated by WHO regions ranged from 21% to 34%. There were no statistical differences in prevalence estimates between samples of men and women.Conclusion Almost one-third of children in low-income and lower-middle-income countries have been exposed to IPV in their lifetime. There was large heterogeneity between estimates that was not explained by available study and sample characteristics. Our findings indicate that children’s exposure to IPV in low-income and lower-middle-income countries is common and widespread; prevention of this major public health exposure should be a priority.PROSPERO registration number CRD42019119698.

Abstract Background Classic epidemic curves – counts of daily events or cumulative events over time –emphasise temporal changes in the growth or size of epidemic outbreaks. Like any graph, these curves have limitations: they are impractical for comparisons of large and small outbreaks or of asynchronous outbreaks, and they do not display the relative growth rate of the epidemic. Our aim was to propose two additional graphical displays for the monitoring of epidemic outbreaks that overcome these limitations. Methods The first graph shows the growth of the epidemic as a function of its size; specifically, the logarithm of new cases on a given day, N(t), is plotted against the logarithm of cumulative cases C(t). Logarithm transformations facilitate comparisons of outbreaks of different sizes, and the lack of a time scale overcomes the need to establish a starting time for each outbreak. Notably, on this graph, exponential growth corresponds to a straight line with a slope equal to one. The second graph represents the logarithm of the relative rate of growth of the epidemic over time; specifically, log10(N(t)/C(t-1)) is plotted against time (t) since the 25th event. We applied these methods to daily death counts attributed to COVID-19 in selected countries, reported up to June 5, 2020. Results In most countries, the log(N) over log(C) plots showed initially a near-linear increase in COVID-19 deaths, followed by a sharp downturn. They enabled comparisons of small and large outbreaks (e.g., Switzerland vs UK), and identified outbreaks that were still growing at near-exponential rates (e.g., Brazil or India). The plots of log10(N(t)/C(t-1)) over time showed a near-linear decrease (on a log scale) of the relative growth rate of most COVID-19 epidemics, and identified countries in which this decrease failed to set in in the early weeks (e.g., USA) or abated late in the outbreak (e.g., Portugal or Russia). Conclusions The plot of log(N) over log(C) displays simultaneously the growth and size of an epidemic, and allows easy identification of exponential growth. The plot of the logarithm of the relative growth rate over time highlights an essential parameter of epidemic outbreaks.

Abstract Background Optimal clinical care of patients with chronic kidney disease (CKD) requires collaboration between primary care physicians (PCPs) and nephrologists. We undertook a randomised trial to determine the impact of superimposed nephrologist care compared to guidelines-directed management by PCPs in CKD patients after hospital discharge. Methods Stage 3b-4 CKD patients were enrolled during a hospitalization and randomised in two arms: Co-management by PCPs and nephrologists (interventional arm) versus management by PCPs with written instructions and consultations by nephrologists on demand (standard care). Our primary outcome was death or rehospitalisation within the 2 years post-randomisation. Secondary outcomes were: urgent renal replacement therapy (RRT), decline of renal function and decrease of quality of life at 2 years. Results From November 2009 to the end of June 2013, we randomised 242 patients. Mean follow-up was 51 + 20 months. Survival without rehospitalisation, GFR decline and elective dialysis initiation did not differ between the two arms. Quality of life was also similar in both groups. Compared to randomised patients, those who either declined to participate in the study or were previously known by nephrologists had a worse survival. Conclusion These results do not demonstrate a benefit of a regular renal care compared to guided PCPs care in terms of survival or dialysis initiation in CKD patients. Increased awareness of renal disease management among PCPs may be as effective as a co-management by PCPs and nephrologists in order to improve the prognosis of moderate-to-severe CKD. Trial registration This study was registered on June 29, 2009 in clinicaltrials.gov ( NCT00929760 ) and adheres to CONSORT 2010 guidelines.

Abstract Background High patient participation in clinical research reduces selection bias and ensures the generalizability of study findings. We explored study-related factors that may influence patients’ willingness to participate in research. Methods We submitted by mail two vignettes that described clinical research studies – a drug trial and a diagnostic study – to patients recently discharged from hospital and assessed their willingness to participate. We used a factorial design to randomly allocate three study attributes per vignette: in the drug trial, presumed superiority of new drug versus equipoise, public versus industry funding, and random versus non-random treatment allocation; in the diagnostic study, common versus rare disease, genetic versus protein analysis, and automatic reporting of results versus reporting on request. Results Of 2600 patients contacted, 1140 (44%) participated. Globally, willingness to participate in a drug trial was lower than in a diagnostic study (44.8% vs. 76.2%; P

Abstract Background Compared to lobectomy by video-assisted thoracic surgery (VATS), segmentectomy by VATS has a potential higher risk of postoperative atelectasis and air leakage. We compared postoperative complications between these two procedures, and analyzed their risk factors. Methods We reviewed the records of all patients who underwent anatomical pulmonary resections by VATS from January 2014 to March 2018 in two Swiss university hospitals. All complications were reported. A logistic regression model was used to compare the risks of complications for the two interventions. Adjustment for patient characteristics was performed using a propensity score, and by including risk factors separately. Results Among 690 patients reviewed, the major indication for lung resection was primary lung cancer (86.4%) followed by metastasis resection (5.8%), benign lesion (3.9%), infection (3.2%) and emphysema (0.7%). Postoperatively, there were 80 instances (33.3%) of complications in 240 segmentectomies, and 171 instances (38.0%) of complications in 450 lobectomies (P = 0.73). After adjustment for the patient’s propensity to be treated by segmentectomy rather than lobectomy, the risks of a complication remained comparable for the two techniques (odds ratio for segmentectomy 0.91 (0.61–1.30), p = 0.59). Length of hospital stay and drainage duration were shorter after segmentectomy. On multivariate analysis, an American Society of Anesthesiologists score above 2 and a forced expiratory volume in one second below 80% of predicted value were significantly associated with the occurrence of complications. Conclusions The rate of complications and their grade were similar between segmentectomy and lobectomy by VATS.

Abstract Background Mental health has been shown to improve after total hip arthroplasty (THA). Little is known about the role of pain and function in this context. We assessed whether change in mental health was associated with improvement in pain and function 1 year post-surgery. Methods This prospective study included patients enrolled in a THA registry from 2010 to 2014. We examined the mental component score (MCS) before and 1 year post-surgery, and 1-year change, in association with Western Ontario McMaster Universities (WOMAC) pain and function scores. All scores were normalized, ranging from 0 to 100 (larger score indicating better outcome). Analyses were adjusted for potential confounders. Results Our study included 610 participants, of which 53% were women. Descriptive statistics are as follows: the average (SD) for age (years) was 68.5 (11.8), and for BMI was 26.9 (4.9). In addition, the MCS average (SD) at baseline was 44.7 (11.2), and at 1-year after THA was 47.5 (10.5). The average change from baseline to 1-year post-THA in MCS was 2.8 (95% CI: 1.9, 3.6), for an effect size of 0.26. As for the WOMAC pain score, the average change from baseline to 1-year post-THA was 44.2 (95%CI: 42.4, 46.0), for an effect size of 2.5. The equivalent change in WOMAC function was 38.1 (95% CI: 36.2, 40.0), for an effect size of 2.0. Results from multivariable analysis controlling for covariates showed that an improvement of 10 points in the 1-year change in pain score resulted in a 0.78 point (95%: CI 0.40, 1.26) increase in the 1-year change in MCS, whereas a 10-point improvement in the 1-year change in function was associated with a 0.94 point (95% CI: 0.56, 1.32) increase. Conclusions Mental health significantly improved from baseline to 1-year post-THA. Greater improvement in pain and function was associated with greater improvement in mental health 1 year post-THA.

Abstract Background Acute abdominal pain accounts for about 10% of emergency department visits and has progressively become the primary indication for CT scanning in most centers. The goal of our study is to identify biological or clinical variables able to predict or rule out significant pathology (conditions requiring urgent medical or surgical treatment) on abdominal CT in patients presenting to an emergency department with acute abdominal pain. Methods This was a retrospective cohort study performed in the emergency department of an academic center with an annual census of 60′000 patients. One hundred and-nine consecutive patients presenting with an acute non-traumatic abdominal pain, not suspected of appendicitis or renal colic, during the first semester of 2013, who underwent an abdominal CT were included. Two medical students, completing their last year of medical school, extracted the data from patients’ electronic health record. Ambiguities in the formulations of clinical symptoms and signs in the patients’ records were solved by consulting a board certified emergency physician. Nine clinical and biological variables were extracted: shock index, peritonism, abnormal bowel sounds, fever (> 38 °C), intensity and duration of the pain, leukocytosis (white blood cell count >11G/L), relative lymphopenia (

Introduction: Health research is gradually embracing a more collectivist approach, fueled by a new movement of open science, data sharing and collaborative partnerships. However, the existence of systemic contradictions hinders the sharing of health data and such collectivist endeavor. Therefore, this qualitative study explores these systemic barriers to a fair sharing of health data from the perspectives of Swiss stakeholders.Methods: Purposive and snowball sampling were used to recruit 48 experts active in the Swiss healthcare domain, from the research/policy-making field and those having a high position in a health data enterprise (e.g., health register, hospital IT data infrastructure or a national health data initiative). Semi-structured interviews were then conducted, audio-recorded, verbatim transcribed with identifying information removed to guarantee the anonymity of participants. A theoretical thematic analysis was then carried out to identify themes and subthemes related to the topic of systemic fairness for sharing health data.Results: Two themes related to the topic of systemic fairness for sharing health data were identified, namely (i) the hypercompetitive environment and (ii) the legal uncertainty blocking data sharing. The theme, hypercompetitive environment was further divided into two subthemes, (i) systemic contradictions to fair data sharing and the (ii) need of fair systemic attribution mechanisms.Discussion: From the perspectives of Swiss stakeholders, hypercompetition in the Swiss academic system is hindering the sharing of health data for secondary research purposes, with the downside effect of influencing researchers to embrace individualism for career opportunities, thereby opposing the data sharing movement. In addition, there was a perceived sense of legal uncertainty from legislations governing the sharing of health data, which adds unreasonable burdens on individual researchers, who are often unequipped to deal with such facets of their data sharing activities.

Introduction Lopinavir/ritonavir (LPV/r) has been proposed as repurposed drugs for pre-exposure and postexposure prophylaxis as well as therapy of COVID-19. Coronavirus postexposure prophylaxis (COPEP) trial aims at assessing their efficacy as postexposure ring-prophylaxis among adults exposed to SARS-CoV-2.Methods and analysis COPEP is a two-arm open-label cluster-randomised trial conducted in three cantons of Switzerland. Asymptomatic contacts (≥16 years) of individuals diagnosed with COVID-19 will be randomised (2:1) to either LPV/r (400 mg/100 mg two times per day) for 5 days, or a standard of care arm (no treatment). Asymptomatic individuals may be either SARS-CoV-2 positive or negative. Contacts living in the single household will form a cluster and will be randomised into the same arm. All participants will be followed-up for 21 days and undergo daily monitoring for COVID-19 symptoms. The primary endpoint is 21-day incidence of laboratory-confirmed COVID-19 with ≥1 compatible symptom, analysed in an intention-to-treat (ITT) analysis. The secondary endpoints include the 21-day incidence of COVID-19 as well as SARS-CoV-2 infection in a modified ITT analysis, excluding participants who had a positive SARS-CoV-2 RT-PCR from oropharyngeal swab and/or a positive SARS-CoV-2 IgG serology at baseline. Assuming a 21-day incidence for COVID-19 of 20% among contacts without postexposure chemoprophylaxis, to detect a relative risk reduction of 60% (ie, translating in an absolute reduction from 20% to 8%), with a power of 80%, an alpha of 5%. Accounting for design effect of cluster design of circa 1.1, we plan to enrol 200 participants to the LPV/r arm and 100 to the standard of care arm, 300 participants in total.Ethics and dissemination Ethics approval has been granted by the Commission Cantonale d’Ethique de la Recherche, Ethikkommission Nordwest- und Zentralschweiz and Comitato Etico Cantonale (ref 2020-00864) and Swissmedic (2020DR3056). Results from this trial will be disseminated via journal articles and presentations at national and international conferences.Trial registration number Clinicaltrials.gov Registry (NCT04364022); Swiss National Clinical Trial Portal Registry (SNCTP 000003732).Registered report identifier CCER 2020-0864.

Abstract Background A higher chance of survival is a key justification for admission to the intensive care unit (ICU). This implies that physicians should be able to accurately estimate a patient’s prognosis, whether cared for on the ward or in the ICU. We aimed to determine whether physicians’ survival predictions correlate with the admission decisions and with patients’ observed survival. Consecutive ICU consultations for internal medicine patients were included. The ICU physician and the internist were asked to predict patient survival with intensive care and with care on the ward using 5 categories of probabilities ( 90%). Patient mortality at 28 days was recorded. Results Thirty ICU physicians and 97 internists assessed 201 patients for intensive care. Among the patients, 140 (69.7%) were admitted to the ICU. Fifty-eight (28.9%) died within 28 days. Admission to intensive care was associated with predicted survival gain in the ICU, particularly for survival estimates made by ICU physicians. Observed survival was associated with predicted survival, for both groups of physicians. The discrimination of the predictions for survival with intensive care, measured by the area under the ROC curve, was 0.63 for ICU physicians and 0.76 for internists; for survival on the ward the areas under the ROC curves were 0.69 and 0.74, respectively. Conclusions Physicians are able to predict survival probabilities when they assess patients for intensive care, albeit imperfectly. Internists are more accurate than ICU physicians. However, ICU physicians’ estimates more strongly influence the admission decision. Closer collaboration between ICU physicians and internists is needed.

Abstract Background We aimed to describe clinical characteristics of patients with community-acquired acute kidney injury (CA-AKI), the effectiveness of initial management of CA-AKI, its prognosis and the impact of medication on its occurrence in patients with previous chronic kidney injury (CKI). Methods We undertook a prospective observational study within the Emergency Department (ED) of a University Hospital, screening for any patient >16 years admitted with an eGFR

Abstract Background Due to its potential impact on women’s psychological health, assessing perceptions of their childbirth experience is important. The aim of this study was to develop a multidimensional self-reporting questionnaire to evaluate the childbirth experience. Methods Factors influencing the childbirth experience were identified from a literature review and the results of a previous qualitative study. A total of 25 items were combined from existing instruments or were created de novo. A draft version was pilot tested for face validity with 30 women and submitted for evaluation of its construct validity to 477 primiparous women at one-month post-partum. The recruitment took place in two obstetric clinics from Swiss and French university hospitals. To evaluate the content validity, we compared item responses to general childbirth experience assessments on a numeric, 0 to 10 rating scale. We dichotomized two group assessment scores: “0 to 7” and “8 to 10”. We performed an exploratory factor analysis to identify underlying dimensions. Results In total, 291 women completed the questionnaire (response rate = 61%). The responses to 22 items were statistically significant between the 0 to 7 and 8 to 10 groups for the general childbirth experience assessments. An exploratory factor analysis yielded four sub-scales, which were labelled “relationship with staff” (4 items), “emotional status” (3 items), “first moments with the new born,” (3 items) and “feelings at one month postpartum” (3 items). All 4 scales had satisfactory internal consistency levels (alpha coefficients from 0.70 to 0.85). The full 25-item version can be used to analyse each item by itself, and the short 4-dimension version can be scored to summarize the general assessment of the childbirth experience. Conclusions The Questionnaire for Assessing the Childbirth Experience (QACE) could be useful as a screening instrument to identify women with negative childbirth experiences. It can be used as both a research instrument in its short version and a questionnaire for use in clinical practice in its full version.

Abstract Background To assess the impact of disease activity on health-related quality of life (HRQoL) in systemic lupus erythematosus (SLE). Methods Cross-sectional study of patients included in the Swiss SLE Cohort Study between April 2007 and June 2014. HRQoL outcomes were based on the Medical Outcome Study Short Form 36 (SF-36). Disease activity was assessed by the SLE Disease Activity Index score with the Safety of Estrogens in SLE National Assessment modification (SELENA-SLEDAI) and by the physican’s global assessment (PGA). Results Of the 252 patients included, 207 (82%) were women. Median [interquartile range (IQR)] age was 43 [32–57] years. SLE was active in 125 patients (49.6%). Median [IQR] mental component summary (MCS) in active vs inactive SLE was 40.0 [30.2–51.0] compared to 47.3 [39.2–52.8] (p

An amendment to this paper has been published and can be accessed via the original article.

BACKGROUND:Strongyloidiasis can be fatal in immunocompromised patients, but few epidemiological studies investigated the burden of this neglected tropical disease among these populations, particularly in low- and middle-income countries such as Bolivia. This study aimed to fill in this gap by estimating prevalence rate and risk factors associated with strongyloidiasis among patients at high risk of complications. METHODS:A cross-sectional study was carried out in Santa Cruz (elevation 400 meters, tropical climate) and Cochabamba (elevation 2,500 meters, temperate climate), among patients with cancer, HIV infection and rheumatic or hematologic disease, using four coproparasitological techniques and one serological (ELISA) test. RESULTS:In total, 1,151 patients participated in this study, including individuals who were HIV-positive (30%) or with rheumatic (29%), oncologic (32%) or hematologic (9%) diseases. The serological and coproparasitological prevalence was 23.0% (95% confidence interval [CI], 20.7-25.5; n = 265/1151) and 7.6% (95% CI, 6.2-9.3; n = 88/1151), respectively, with an estimated actual prevalence of 20.2% (95% CI, 17.9-22.5). Positive serology and positive coproparasitology were associated with younger age and lower education levels. There was no significant difference in prevalence between Cochabamba and Santa Cruz as defined by coproparasitology (6.4% vs. 8.9%; p = 0.11) or serology (24.0% vs. 22.0%; p = 0.4). Among 64 patients in Cochabamba who had never travelled to the tropical lowlands, 5 (7.8%) had a positive coproparasitology. CONCLUSIONS:Strongyloidiasis is widely prevalent in Bolivia among vulnerable patients at increased risk of life-threatening complications. Transmission of the parasite occurs both in tropical lowlands and temperate elevation (≥ 2,500 m). Control strategies to prevent transmission and complications of this serious parasitic disease should be urgently reinforced.

Abstract Background There is currently no guidance for selecting a specific difference to be detected in a superiority trial. We explored 3 factors that in our opinion should influence the difference to be detected (type of outcome, patient age group, and presence of treatment side-effects), and 3 that should not (baseline level of risk, logistical difficulties, and cost of treatment). Methods We conducted an experimental survey using a factorial design among 380 corresponding authors of randomized controlled trials indexed in Medline. Two hypothetical vignettes were submitted to participants: one described a trial of a new analgesic in mild trauma injuries, the other described a trial of a new chemotherapy among cancer patients. The first vignette tested the baseline level of risk, patient age-group, patient recruitment difficulties, and treatment side-effects. The second tested the baseline level of risk, patient age-group, type of outcome, and cost of treatment. The respondents were asked to select the smallest gain of effectiveness that should be detected by the trial. Results In vignette 1, respondents selected a median difference to be detected corresponding to an improvement of 7.0 % in pain control with the new treatment. In vignette 2, they selected a median difference to be detected corresponding to a reduction of 5.0 % in mortality or cancer recurrence with the new chemotherapy. In both vignettes, the difference to be detected decreased significantly with the baseline risk. The other factor influencing difference to be detected was the age group, but the impact of this factor was smaller. Cost, side-effects, outcome severity, or mention of logistical difficulties did not significantly impact the difference to be detected selected by participants. Conclusions Three of the anticipated effects conformed to our expectations (the effect of patient age, and absence of effect of the cost of treatment and of patient recruitment difficulties) and the other three did not. These findings can guide future research in determining differences to be detected in trials that can translate to meaningful clinical decision-making.

Treponema pallidum PCR (Tp-PCR) has been noted as a valid method for diagnosing syphilis. We compared Tp-PCR to a combination of darkfield microscopy (DFM), the reference method, and serologic testing in a cohort of 273 patients from France and Switzerland and found the diagnostic accuracy of Tp-PCR was higher than that for DFM.