Center dEpidemiologie Clinique

Hôpital-Camfrout, France

Center dEpidemiologie Clinique

Hôpital-Camfrout, France
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Touze E.,University of Paris Descartes | Touze E.,University of Caen Lower Normandy | Trinquart L.,University of Paris Pantheon Sorbonne | Felgueiras R.,Center dEpidemiologie Clinique | And 10 more authors.
Stroke | Year: 2013

BACKGROUND AND PURPOSE - Compared with carotid endarterectomy (CEA), carotid angioplasty and stenting (CAS) is associated with a higher risk of procedural stroke or death especially in patients with symptomatic stenosis. However, after the perioperative period, risk is similar with both treatments, suggesting that CAS could be an acceptable option in selected patients. METHODS - We performed systematic reviews of observational studies of procedural risks of CEA or CAS and extracted data on 9 predefined risk factors (age, contralateral carotid occlusion, coronary artery disease, diabetes mellitus, sex, hypertension, peripheral artery disease, and type and side of stenosis). We calculated pooled relative risks of procedural stroke or death. Factors with differential effects on risk of CAS versus CEA were identified by interaction tests and used to derive a rule. The rule was tested using individual patient data from randomized trials of CAS versus CEA from the Carotid Stenting Trialists' Collaboration (CSTC). RESULTS - We identified 170 studies. The effects of sex, contralateral occlusion, age, and restenosis (SCAR) on the procedural risk of stroke or death differed. Patients with contralateral occlusion or restenosis and women <75 years were at relatively low risk for CAS (SCAR negative), with all others being high risk (SCAR positive). Among the 3049 patients in the CSTC validation, 694 (23%) patients were SCAR negative. The pooled RR of procedural stroke and death with CAS versus CEA was 0.93 (0.49-1.77; P=0.83) in SCAR-negative and 2.41 (1.68-3.45; P<0.0001) in SCAR-positive patients (P [interaction]=0.05). CONCLUSIONS - The SCAR rule is potentially useful to identify patients in whom CAS has a similar risk of perioperative stroke or death to CEA. © 2013 American Heart Association, Inc.

Escalas C.,French Institute of Health and Medical Research | Dalichampt M.,Assistance Publique Hopitaux de Paris | Combe B.,Montpellier University Hospital Center | Fautrel B.,University Pierre and Marie Curie | And 5 more authors.
Annals of the Rheumatic Diseases | Year: 2012

Objective: To assess the association of adherence to the 2007 recommendations of the European League Against Rheumatism (EULAR) for managing early arthritis and radiographic progression and disability in patients Methods: The authors conducted a prospective population-based cohort study. The ESPOIR cohort was a French cohort of 813 patients with early arthritis not receiving disease-modifying antirheumatic drugs (DMARDs). Adherence to the 2007 EULAR recommendations was defined by measuring adherence to three of the recommendations concerning the initiation and early adjustment of DMARDs. The study endpoints were radiographic progression, defined as the presence of at least one new erosion between baseline and 1 year, and disability as a heath assessment questionnaire score ≥1 at 2 years. A propensity score of being treated according to the recommendations was developed. Results: After adjustment for propensity score, treatment centre and the main confounding factors, patients without recommendation adherence were at increased risk of radiographic progression at 1 year, and of functional impairment at 2 years (OR 1.98, (95% CI: 1.08 to 3.62 and OR: 2.36, (95% CI: 1.17 to 4.67), respectively). Conclusions: Early arthritis patients whose treatment adhered to the 2007 EULAR recommendations seemed to benefit from such treatment in terms of risk of clinical and radiographic progression. Using a propensity score of being treated according to recommendations in observational studies may be useful in assessing the potential impact of these recommendations on outcome. Copyright Article author (or their employer) 2012.

Dechartres A.,French Institute of Health and Medical Research | Dechartres A.,Center dEpidemiologie Clinique | Dechartres A.,University of Paris Descartes | Altman D.G.,Center for Statistics in Medicine | And 11 more authors.
JAMA - Journal of the American Medical Association | Year: 2014

IMPORTANCE: A persistent dilemma when performing meta-analyses is whether all available trials should be included in the meta-analysis. OBJECTIVES: To compare treatment outcomes estimated by meta-analysis of all trials and several alternative analytic strategies: single most precise trial (ie, trial with the narrowest confidence interval), meta-analysis restricted to the 25% largest trials, limit meta-analysis (a meta-analysis model adjusted for small-study effect), and meta-analysis restricted to trials at low overall risk of bias. DATA SOURCES: One hundred sixty-three meta-analyses published between 2008 and 2010 in high-impact-factor journals and between 2011 and 2013 in the Cochrane Database of Systematic Reviews: 92 (705 randomized clinical trials [RCTs]) with subjective outcomes and 71 (535 RCTs) with objective outcomes. DATA SYNTHESIS: For each meta-analysis, the difference in treatment outcomes between meta-analysis of all trials and each alternative strategy, expressed as a ratio of odds ratios (ROR), was assessed considering the dependency between strategies. A difference greater than 30% was considered substantial. RORs were combined by random-effects meta-analysis models to obtain an average difference across the sample. An ROR greater than 1 indicates larger treatment outcomes with meta-analysis of all trials. Subjective and objective outcomes were analyzed separately. RESULTS: Treatment outcomes were larger in the meta-analysis of all trials than in the single most precise trial (combined ROR, 1.13 [95%CI, 1.07-1.19]) for subjective outcomes and 1.03 (95%CI, 1.01-1.05) for objective outcomes). The difference in treatment outcomes between these strategies was substantial in 47 of 92 (51%) meta-analyses of subjective outcomes (meta-analysis of all trials showing larger outcomes in 40/47) and in 28 of 71 (39%) meta-analyses of objective outcomes (meta-analysis of all trials showing larger outcomes in 21/28). The combined ROR for subjective and objective outcomes was, respectively, 1.08 (95%CI, 1.04-1.13) and 1.03 (95%CI, 1.00-1.06) when comparing meta-analysis of all trials and meta-analysis of the 25% largest trials, 1.17 (95%CI, 1.11-1.22) and 1.13 (95%CI, 0.82-1.55) when comparing meta-analysis of all trials and limit meta-analysis, and 0.94 (95%CI, 0.86-1.04) and 1.03 (95%CI, 1.00-1.06) when comparing meta-analysis of all trials and meta-analysis restricted to trials at low risk of bias. CONCLUSIONS AND RELEVANCE: Estimation of treatment outcomes in meta-analyses differs depending on the strategy used. This instability in findings can result in major alterations in the conclusions derived from the analysis and underlines the need for systematic sensitivity analyses.

Lonjon G.,French Institute of Health and Medical Research | Boutron I.,French Institute of Health and Medical Research | Boutron I.,Center dEpidemiologie Clinique | Boutron I.,University of Paris Descartes | And 14 more authors.
Annals of Surgery | Year: 2014

OBJECTIVE: We aimed to compare treatment effect estimates from NRSs with PS analysis and RCTs of surgery. BACKGROUND: Evaluating a surgical procedure in randomized controlled trials (RCTs) is challenging. Nonrandomized studies (NRSs) involving use of propensity score (PS) analysis to limit bias are of increasing interest. DESIGN: Meta-epidemiological study. METHODS: We systematically searched MEDLINE via PubMed for all prospective NRSs with PS analysis evaluating a surgical procedure. Related RCTs, addressing the same clinical questions, were systematically retrieved. Our primary outcome of interest was all-cause mortality. We also selected 1 subjective outcome. We calculated the summary odds ratios (OR) for each study design, the ratio of OR (ROR) between the designs and the summary ROR across clinical questions. An ROR < 1 indicated that the experimental intervention is more favorable in NRSs with PS analysis than RCTs. RESULTS: We retrieved 70 reports of NRSs with PS analysis and 94 related RCTs evaluating 31 clinical questions, of which 22 assessed all-cause mortality and 26 a subjective outcome. The combined ROR for all-cause mortality was 0.83 (95% confidence interval: 0.65-1.04). For subjective outcomes, the combined ROR was 1.07 (0.87-1.33). CONCLUSIONS: There was no statistically significant difference in treatment effect between NRSs with PS analysis and RCTs. Prospective NRSs with suitable and careful PS analysis can be relied upon as evidence when RCTs are not possible. Copyright © 2013 by Lippincott Williams & Wilkins.

Yavchitz A.,French Institute of Health and Medical Research | Yavchitz A.,Center dEpidemiologie Clinique | Yavchitz A.,University of Paris Descartes | Boutron I.,French Institute of Health and Medical Research | And 11 more authors.
PLoS Medicine | Year: 2012

Background: Previous studies indicate that in published reports, trial results can be distorted by the use of "spin" (specific reporting strategies, intentional or unintentional, emphasizing the beneficial effect of the experimental treatment). We aimed to (1) evaluate the presence of "spin" in press releases and associated media coverage; and (2) evaluate whether findings of randomized controlled trials (RCTs) based on press releases and media coverage are misinterpreted. Methods and Findings: We systematically searched for all press releases indexed in the EurekAlert! database between December 2009 and March 2010. Of the 498 press releases retrieved and screened, we included press releases for all two-arm, parallel-group RCTs (n = 70). We obtained a copy of the scientific article to which the press release related and we systematically searched for related news items using Lexis Nexis. "Spin," defined as specific reporting strategies (intentional or unintentional) emphasizing the beneficial effect of the experimental treatment, was identified in 28 (40%) scientific article abstract conclusions and in 33 (47%) press releases. From bivariate and multivariable analysis assessing the journal type, funding source, sample size, type of treatment (drug or other), results of the primary outcomes (all nonstatistically significant versus other), author of the press release, and the presence of "spin" in the abstract conclusion, the only factor associated, with "spin" in the press release was "spin" in the article abstract conclusions (relative risk [RR] 5.6, [95% CI 2.8-11.1], p<0.001). Findings of RCTs based on press releases were overestimated for 19 (27%) reports. News items were identified for 41 RCTs; 21 (51%) were reported with "spin," mainly the same type of "spin" as those identified in the press release and article abstract conclusion. Findings of RCTs based on the news item was overestimated for ten (24%) reports. Conclusion: "Spin" was identified in about half of press releases and media coverage. In multivariable analysis, the main factor associated with "spin" in press releases was the presence of "spin" in the article abstract conclusion. © 2012 Yavchitz et al.

Boutron I.,University of Oxford | Boutron I.,French Institute of Health and Medical Research | Boutron I.,Center dEpidemiologie Clinique | Boutron I.,University of Paris Descartes | And 5 more authors.
JAMA - Journal of the American Medical Association | Year: 2010

Context: Previous studies indicate that the interpretation of trial results can be distorted by authors of published reports. Objective: To identify the nature and frequency of distorted presentation or "spin" (ie, specific reporting strategies, whatever their motive, to highlight that the experimental treatment is beneficial, despite a statistically nonsignificant difference for the primary outcome, or to distract the reader from statistically nonsignificant results) in published reports of randomized controlled trials (RCTs) with statistically nonsignificant results for primary outcomes. Data Sources: March 2007 search of MEDLINE via PubMed using the Cochrane Highly Sensitive Search Strategy to identify reports of RCTs published in December 2006. Study Selection: Articles were included if they were parallel-group RCTs with a clearly identified primary outcome showing statistically nonsignificant results (ie, P≥.05). Data Extraction: Two readers appraised each selected article using a pretested, standardized data abstraction form developed in a pilot test. Results: From the 616 published reports of RCTs examined, 72 were eligible and appraised. The title was reported with spin in 13 articles (18.0%; 95% confidence interval [Cl], 10.0%-28.9%). Spin was identified in the Results and Conclusions sections of the abstracts of 27 (37.5%; 95% Cl, 26.4%-49.7%) and 42 (58.3%; 95% Cl, 46.1%-69.8%) reports, respectively, with the conclusions of 17 (23.6%; 95% Cl, 14.4%-35.1%) focusing only on treatment effectiveness. Spin was identified in the main-text Results, Discussion, and Conclusions sections of 21 (29.2%; 95% Cl, 19.0%-41.1%), 31 (43.1%; 95% Cl, 31.4%-55.3%), and 36 (50.0%; 95% Cl, 38.0%-62.0%) reports, respectively. More than 40% of the reports had spin in at least 2 of these sections in the main text. Conclusion: In this representative sample of RCTs published in 2006 with statistically nonsignificant primary outcomes, the reporting and interpretation of findings was frequently inconsistent with the results. ©2010 American Medical Association. All rights reserved.

Giraudeau B.,Center Cochrane Francais | Higgins J.P.T.,University of Bristol | Tavernier E.,French Institute of Health and Medical Research | Trinquart L.,Center Cochrane Francais | And 3 more authors.
Statistics in Medicine | Year: 2016

Meta-epidemiological studies are used to compare treatment effect estimates between randomized clinical trials with and without a characteristic of interest. To our knowledge, there is presently nothing to help researchers to a priori specify the required number of meta-analyses to be included in a meta-epidemiological study. We derived a theoretical power function and sample size formula in the framework of a hierarchical model that allows for variation in the impact of the characteristic between trials within a meta-analysis and between meta-analyses. A simulation study revealed that the theoretical function overestimated power (because of the assumption of equal weights for each trial within and between meta-analyses). We also propose a simulation approach that allows for relaxing the constraints used in the theoretical approach and is more accurate. We illustrate that the two variables that mostly influence power are the number of trials per meta-analysis and the proportion of trials with the characteristic of interest. We derived a closed-form power function and sample size formula for estimating the impact of trial characteristics in meta-epidemiological studies. Our analytical results can be used as a 'rule of thumb' for sample size calculation for a meta-epidemiologic study. A more accurate sample size can be derived with a simulation study. © 2016 John Wiley & Sons, Ltd.

Trinquart L.,Center dEpidemiologie Clinique | Attiche N.,Center dEpidemiologie Clinique | Bafeta A.,Center dEpidemiologie Clinique | Porcher R.,Center dEpidemiologie Clinique | Ravaud P.,Center dEpidemiologie Clinique
Annals of Internal Medicine | Year: 2016

Background: Ranking of interventions is one of the most appealing elements of network meta-analysis. There is, however, little evidence about the reliability of these rankings. Purpose: To empirically evaluate the extent of uncertainty in intervention rankings from network meta-analysis. Data Sources: Two previous systematic reviews that involved searches of the Cochrane Library, MEDLINE, and Embase up to July 2012 for articles that included networks of at least 3 interventions. Study Selection: 58 network meta-analyses involving 1308 randomized trials and 404 interventions with available aggregated outcome data. Data Analysis: Each network was analyzed with a Bayesian approach. For each intervention, the surface under the cumulative ranking curve (SUCRA) and its 95% credible interval (95% CrI) were estimated. Through use of the SUCRA values, the interventions were then rank-ordered between 0% (worst) and 100% (best). Data Synthesis: The median width of the 95% CrIs of the SUCRA was 65% (first to third quartile, 38% to 80%). In 28% of networks, there was a 50% or greater probability that the best-ranked treatment was actually not the best. No evidence showed a difference between the best-ranked intervention and the second and third best-ranked interventions in 90% and 71% of comparisons, respectively. In 39 networks with 6 or more interventions, the median probability that 1 of the top 2 interventions was among the bottom 2 was 35% (first to third quartile, 14% to 59%). Limitation: This analysis did not consider such factors as the risk of bias within trials or small-study effects that may affect the reliability of rankings. Conclusion: Treatment rankings derived from network meta-analyses have a substantial degree of imprecision. Authors and readers should interpret such rankings with great caution.

Giraudeau B.,French Institute of Health and Medical Research | Giraudeau B.,University of Tours | Caille A.,French Institute of Health and Medical Research | Caille A.,University of Tours | And 4 more authors.
PLoS ONE | Year: 2012

Background: The Nuremberg code defines the general ethical framework of medical research with participant consent as its cornerstone. In cluster randomized trials (CRT), obtaining participant informed consent raises logistic and methodologic concerns. First, with randomization of large clusters such as geographical areas, obtaining individual informed consent may be impossible. Second, participants in randomized clusters cannot avoid certain interventions, which implies that participant informed consent refers only to data collection, not administration of an intervention. Third, complete participant information may be a source of selection bias, which then raises methodological concerns. We assessed whether participant informed consent was required in such trials, which type of consent was required, and whether the trial was at risk of selection bias because of the very nature of participant information. Methods and Findings: We systematically reviewed all reports of CRT published in MEDLINE in 2008 and surveyed corresponding authors regarding the nature of the informed consent and the process of participant inclusion. We identified 173 reports and obtained an answer from 113 authors (65.3%). In total, 23.7% of the reports lacked information on ethics committee approval or participant consent, 53.1% of authors declared that participant consent was for data collection only and 58.5% that the group allocation was not specified for participants. The process of recruitment (chronology of participant recruitment with regard to cluster randomization) was rarely reported, and we estimated that only 56.6% of the trials were free of potential selection bias. Conclusions: For CRTs, the reporting of ethics committee approval and participant informed consent is less than optimal. Reports should describe whether participants consented for administration of an intervention and/or data collection. Finally, the process of participant recruitment should be fully described (namely, whether participants were informed of the allocation group before being recruited) for a better appraisal of the risk of selection bias. © 2012 Giraudeau et al.

Chauvin A.,University of Paris Descartes | Chauvin A.,University of Paris Pantheon Sorbonne | Ravaud P.,Center dEpidemiologie Clinique | Ravaud P.,University of Paris Descartes | And 8 more authors.
BMC Medicine | Year: 2015

Background: The peer review process is a cornerstone of biomedical research publications. However, it may fail to allow the publication of high-quality articles. We aimed to identify and sort, according to their importance, all tasks that are expected from peer reviewers when evaluating a manuscript reporting the results of a randomized controlled trial (RCT) and to determine which of these tasks are clearly requested by editors in their recommendations to peer reviewers. Methods: We identified the tasks expected of peer reviewers from 1) a systematic review of the published literature and 2) recommendations to peer reviewers for 171 journals (i.e., 10 journals with the highest impact factor for 14 different medical areas and all journals indexed in PubMed that published more than 15 RCTs over 3 months regardless of the medical area). Participants who had peer-reviewed at least one report of an RCT had to classify the importance of each task relative to other tasks using a Q-sort technique. Finally, we evaluated editors' recommendations to authors to determine which tasks were clearly requested by editors in their recommendations to peer reviewers. Results: The Q-sort survey was completed by 203 participants, 93 (46 %) with clinical expertise, 72 (36 %) with methodological/statistical expertise, 17 (8 %) with expertise in both areas, and 21 (10 %) with other expertise. The task rated most important by participants (evaluating the risk of bias) was clearly requested by only 5 % of editors. In contrast, the task most frequently requested by editors (provide recommendations for publication), was rated in the first tertile only by 21 % of all participants. Conclusions: The most important tasks for peer reviewers were not congruent with the tasks most often requested by journal editors in their guidelines to reviewers. © 2015 Chauvin et al.

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