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1.
BMC Med Res Methodol ; 20(1): 64, 2020 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-32171256

RESUMO

BACKGROUND: Among different investigators studying the same exposures and outcomes, there may be a lack of consensus about potential confounders that should be considered as matching, adjustment, or stratification variables in observational studies. Concerns have been raised that confounding factors may affect the results obtained for the alcohol-ischemic heart disease relationship, as well as their consistency and reproducibility across different studies. Therefore, we assessed how confounders are defined, operationalized, and discussed across individual studies evaluating the impact of alcohol on ischemic heart disease risk. METHODS: For observational studies included in a recent alcohol-ischemic heart disease meta-analysis, we identified all variables adjusted, matched, or stratified for in the largest reported multivariate model (i.e. potential confounders). We recorded how the variables were measured and grouped them into higher-level confounder domains. Abstracts and Discussion sections were then assessed to determine whether authors considered confounding when interpreting their study findings. RESULTS: 85 of 87 (97.7%) studies reported multivariate analyses for an alcohol-ischemic heart disease relationship. The most common higher-level confounder domains included were smoking (79, 92.9%), age (74, 87.1%), and BMI, height, and/or weight (57, 67.1%). However, no two models adjusted, matched, or stratified for the same higher-level confounder domains. Most (74/87, 85.1%) articles mentioned or alluded to "confounding" in their Abstract or Discussion sections, but only one stated that their main findings were likely to be affected by residual confounding. There were five (5/87, 5.7%) authors that explicitly asked for caution when interpreting results. CONCLUSION: There is large variation in the confounders considered across observational studies evaluating the impact of alcohol on ischemic heart disease risk and almost all studies spuriously ignore or eventually dismiss confounding in their conclusions. Given that study results and interpretations may be affected by the mix of potential confounders included within multivariate models, efforts are necessary to standardize approaches for selecting and accounting for confounders in observational studies.

3.
Chem Biol Interact ; 322: 109060, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32171849

RESUMO

BACKGROUND: Individual observational studies have suggested null, weak, linear, and J-shaped associations between alcohol consumption and breast cancer risk. However, observational studies are susceptible to confounders, which can obscure the true impact of an exposure on an outcome. Given the uncertainty regarding the association between alcohol consumption and breast cancer, and the challenges of identifying, measuring, and accounting for all potential confounders, we assessed whether and how authors of observational studies evaluating the impact of alcohol consumption on the risk of breast cancer considered bias when interpreting their main study findings. METHODS: We identified all observational studies included in a recent alcohol-breast cancer meta-analysis. The Abstract and/or Discussion sections were reviewed to determine whether authors considered confounding. RESULTS: Among 101 eligible studies, 73 (72.3%) mentioned confounding explicitly in the Abstract and Discussion sections. There were 33 (32.7%) studies that included statements regarding specific confounders that were not adjusted for in the analyses and 60 (59.4%) studies without any statements about the impact of residual confounding on their main findings. Although none of the studies outlined that their main findings were "likely" to be affected by residual confounding, 25 (24.8%) mentioned a "possible" impact and 16 (15.8%) claimed an "unlikely" impact. Only one (1.0%) article explicitly stated that caution was needed when interpreting their findings due to confounding. CONCLUSION: These results highlight the need for more adequate consideration of the potential impact of residual confounding in observational studies evaluating the impact of alcohol consumption on the risk of breast cancer.


Assuntos
Consumo de Bebidas Alcoólicas , Neoplasias da Mama/etiologia , Neoplasias da Mama/epidemiologia , Bases de Dados Factuais , Feminino , Carga Global da Doença , Humanos , Fatores de Risco
4.
BMJ ; 368: l7078, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32024657

RESUMO

OBJECTIVES: To conduct a systematic review and meta-analysis of the effects of rosiglitazone treatment on cardiovascular risk and mortality using multiple data sources and varying analytical approaches with three aims in mind: to clarify uncertainties about the cardiovascular risk of rosiglitazone; to determine whether different analytical approaches are likely to alter the conclusions of adverse event meta-analyses; and to inform efforts to promote clinical trial transparency and data sharing. DESIGN: Systematic review and meta-analysis of randomized controlled trials. DATA SOURCES: GlaxoSmithKline's (GSK's) ClinicalStudyDataRequest.com for individual patient level data (IPD) and GSK's Study Register platforms, MEDLINE, PubMed, Embase, Web of Science, Cochrane Central Registry of Controlled Trials, Scopus, and ClinicalTrials.gov from inception to January 2019 for summary level data. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomized, controlled, phase II-IV clinical trials that compared rosiglitazone with any control for at least 24 weeks in adults. DATA EXTRACTION AND SYNTHESIS: For analyses of trials for which IPD were available, a composite outcome of acute myocardial infarction, heart failure, cardiovascular related death, and non-cardiovascular related death was examined. These four events were examined independently as secondary analyses. For analyses including trials for which IPD were not available, myocardial infarction and cardiovascular related death were examined, which were determined from summary level data. Multiple meta-analyses were conducted that accounted for trials with zero events in one or both arms with two different continuity corrections (0.5 constant and treatment arm) to calculate odds ratios and risk ratios with 95% confidence intervals. RESULTS: 33 eligible trials were identified from ClinicalStudyDataRequest.com for which IPD were available (21 156 patients). Additionally, 103 trials for which IPD were not available were included in the meta-analyses for myocardial infarction (23 683 patients), and 103 trials for which IPD were not available contributed to the meta-analyses for cardiovascular related death (22 772 patients). Among 29 trials for which IPD were available and that were included in previous meta-analyses using GSK's summary level data, more myocardial infarction events were identified by using IPD instead of summary level data for 26 trials, and fewer cardiovascular related deaths for five trials. When analyses were limited to trials for which IPD were available, and a constant continuity correction of 0.5 and a random effects model were used to account for trials with zero events in only one arm, patients treated with rosiglitazone had a 33% increased risk of a composite event compared with controls (odds ratio 1.33, 95% confidence interval 1.09 to 1.61; rosiglitazone population: 274 events among 11 837 patients; control population: 219 events among 9319 patients). The odds ratios for myocardial infarction, heart failure, cardiovascular related death, and non-cardiovascular related death were 1.17 (0.92 to 1.51), 1.54 (1.14 to 2.09), 1.15 (0.55 to 2.41), and 1.18 (0.60 to 2.30), respectively. For analyses including trials for which IPD were not available, odds ratios for myocardial infarction and cardiovascular related death were attenuated (1.09, 0.88 to 1.35, and 1.12, 0.72 to 1.74, respectively). Results were broadly consistent when analyses were repeated using trials with zero events across both arms and either of the two continuity corrections was used. CONCLUSIONS: The results suggest that rosiglitazone is associated with an increased cardiovascular risk, especially for heart failure events. Although increased risk of myocardial infarction was observed across analyses, the strength of the evidence varied and effect estimates were attenuated when summary level data were used in addition to IPD. Because more myocardial infarctions and fewer cardiovascular related deaths were reported in the IPD than in the summary level data, sharing IPD might be necessary when performing meta-analyses focused on safety. SYSTEMATIC REVIEW REGISTRATION: OSF Home https://osf.io/4yvp2/.


Assuntos
Doenças Cardiovasculares/induzido quimicamente , Hipoglicemiantes/efeitos adversos , Rosiglitazona/efeitos adversos , Doenças Cardiovasculares/mortalidade , Humanos , Hipoglicemiantes/farmacologia , Disseminação de Informação , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Rosiglitazona/farmacologia
5.
Int J Epidemiol ; 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31967637

RESUMO

BACKGROUND: Different analytical approaches can influence the associations estimated in observational studies. We assessed the variability of effect estimates reported within and across observational studies evaluating the impact of alcohol on breast cancer. METHODS: We abstracted largest harmful, largest protective and smallest (closest to the null value of 1.0) relative risk estimates in studies included in a recent alcohol-breast cancer meta-analysis, and recorded how they differed based on five model specification characteristics, including exposure definition, exposure contrast levels, study populations, adjustment covariates and/or model approaches. For each study, we approximated vibration of effects by dividing the largest by the smallest effect estimate [i.e. ratio of odds ratio (ROR)]. RESULTS: Among 97 eligible studies, 85 (87.6%) reported both harmful and protective relative effect estimates for an alcohol-breast cancer relationship, which ranged from 1.1 to 17.9 and 0.0 to 1.0, respectively. The RORs comparing the largest and smallest estimates in value ranged from 1.0 to 106.2, with a median of 3.0 [interquartile range (IQR) 2.0-5.2]. One-third (35, 36.1%) of the RORs were based on extreme effect estimates with at least three different model specification characteristics; the vast majority (87, 89.7%) had different exposure definitions or contrast levels. Similar vibrations of effect were observed when only extreme estimates with differences based on study populations and/or adjustment covariates were compared. CONCLUSIONS: Most observational studies evaluating the impact of alcohol on breast cancer report relative effect estimates for the same associations that diverge by >2-fold. Therefore, observational studies should estimate the vibration of effects to provide insight regarding the stability of findings.

7.
J Am Heart Assoc ; 8(21): e013546, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31617435

RESUMO

Background Improving postoperative recovery is important, with a national focus on postacute care, but the volume and quality of evidence in this area are not well characterized. We conducted a systematic review to characterize studies on postoperative recovery after adult cardiac surgery using patient-reported outcome measures. Methods and Results From MEDLINE and Web of Science, studies were included if they prospectively assessed postoperative recovery on adult patients undergoing cardiac surgery using patient-reported outcome measures. Six recovery domains were defined by prior literature: nociceptive symptoms, mental health, physical function, activities of daily living, sleep, and cognitive function. Of the 3432 studies, 105 articles met the inclusion criteria. The studies were small (median sample size, 119), and mostly conducted in single-center settings (n=81; 77%). Study participants were predominantly men (71%) and white (88%). Coronary artery bypass graft was included in 93% (n=98). Studies commonly selected for elective cases (n=56; 53%) and patients with less comorbidity (n=67; 64%). Median follow-up duration was 91 (interquartile range, 42-182) days. Studies most commonly assessed 1 domain (n=42; 40%). The studies also varied in the instruments used and differed in their reporting approach. Studies commonly excluded patients who died during the follow-up period (n=48; 46%), and 45% (n=47) did not specify how those patients were analyzed. Conclusions Studies of postoperative patient-reported outcome measures are low in volume, most often single site without external validation, varied in their approach to missing data, and narrow in the domains and diversity of patients. The evidence base for postoperative patient-reported outcome measures needs to be strengthened.

8.
BMC Med ; 17(1): 188, 2019 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-31639007

RESUMO

BACKGROUND: There is growing interest in evaluating differences in healthcare interventions across routinely collected demographic characteristics. However, individual subgroup analyses in randomized controlled trials are often not prespecified, adjusted for multiple testing, or conducted using the appropriate statistical test for interaction, and therefore frequently lack credibility. Meta-analyses can be used to examine the validity of potential subgroup differences by collating evidence across trials. Here, we characterize the conduct and clinical translation of age-treatment subgroup analyses in Cochrane reviews. METHODS: For a random sample of 928 Cochrane intervention reviews of randomized trials, we determined how often subgroup analyses of age are reported, how often these analyses have a P < 0.05 from formal interaction testing, how frequently subgroup differences first observed in an individual trial are later corroborated by other trials in the same meta-analysis, and how often statistically significant results are included in commonly used clinical management resources (BMJ Best Practice, UpToDate, Cochrane Clinical Answers, Google Scholar, and Google search). RESULTS: Among 928 Cochrane intervention reviews, 189 (20.4%) included plans to conduct age-treatment subgroup analyses. The vast majority (162 of 189, 85.7%) of the planned analyses were not conducted, commonly because of insufficient trial data. There were 22 reviews that conducted their planned age-treatment subgroup analyses, and another 3 reviews appeared to perform unplanned age-treatment subgroup analyses. These 25 (25 of 928, 2.7%) reviews conducted a total of 97 age-treatment subgroup analyses, of which 65 analyses (in 20 reviews) had non-overlapping subgroup levels. Among the 65 age-treatment subgroup analyses, 14 (21.5%) did not report any formal interaction testing. Seven (10.8%) reported P < 0.05 from formal age-treatment interaction testing; however, none of these seven analyses were in reviews that discussed the potential biological rationale or clinical significance of the subgroup findings or had results that were included in common clinical practice resources. CONCLUSION: Age-treatment subgroup analyses in Cochrane intervention reviews were frequently planned but rarely conducted, and implications of detected interactions were not discussed in the reviews or mentioned in common clinical resources. When subgroup analyses are performed, authors should report the findings, compare the results to previous studies, and outline any potential impact on clinical care.


Assuntos
Interpretação Estatística de Dados , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Projetos de Pesquisa , Literatura de Revisão como Assunto , Distribuição por Idade , Fatores Etários , Projetos de Pesquisa Epidemiológica , Estudos Epidemiológicos , Feminino , Humanos , Medicina de Precisão/métodos , Medicina de Precisão/estatística & dados numéricos , Projetos de Pesquisa/normas , Projetos de Pesquisa/estatística & dados numéricos
11.
JAMA Intern Med ; 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31355868
12.
BMC Med ; 17(1): 117, 2019 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-31203816

RESUMO

BACKGROUND: Postmarketing commitments are clinical studies that pharmaceutical companies agree to conduct at the time of FDA approval, but which are not required by statute or regulation. As FDA increasingly adopts a lifecycle evaluation process, greater emphasis will be placed on postmarket evidence as a component of therapeutic evaluation. Therefore, the objectives of this study were to determine how often postmarketing commitments agreed upon by pharmaceutical companies at first FDA approval lead to new clinical trials and to establish the characteristics and rates of completion and dissemination of postmarketing commitments. METHODS: For new drugs and biologics approved in 2009-2012, we used public FDA documents, ClinicalTrials.gov, and Scopus, to determine postmarketing commitments and their characteristics known at the time of FDA approval; number subject to reporting requirements, for which FDA is required to make study status information available to the public ("506B studies"), and their statuses; and rates of registration and results reporting on ClinicalTrials.gov and publication in peer-reviewed journals for all clinical trials. RESULTS: Among 110 novel drugs and biologics approved by the FDA between 2009 and 2012, 61 (55.5%) had at least one postmarketing commitment at the time of first approval. Of 331 total postmarketing commitments, 33 (10.0%) were for new clinical trials; 27 of these were 506B studies subject to public reporting requirements, of which 12 (44.4%) did not have a recent (i.e., up-to-date) or closed (i.e., fulfilled or released) status provided publicly by the FDA. Although two postmarketing commitments were insufficiently described in FDA records to perform searches on ClinicalTrials.gov, nearly all (28, 90.3%) of the 31 remaining postmarketing commitments for new clinical trials were registered on ClinicalTrials.gov. Among the registered trials, 23 (23 of 28, 82.1%) were classified as completed or terminated, of which 22 (95.7%) had reported results. When considering all 29 completed or terminated clinical trials, registered or unregistered on ClinicalTrials.gov, only half (14, 48.3%) were published in peer-reviewed journals. CONCLUSIONS: While only 15% of postmarketing commitments agreed to by pharmaceutical companies at the time of FDA approval were for new clinical trials, these trials were nearly always registered with reported results on ClinicalTrials.gov. However, only half were published, and despite FDA public reporting requirements, recent status information was often unavailable for 506B studies.


Assuntos
Aprovação de Drogas/métodos , United States Food and Drug Administration/normas , Estudos Transversais , Humanos , Estados Unidos
13.
JAMA Netw Open ; 2(5): e193410, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31074812

RESUMO

Importance: The US Food and Drug Administration (FDA) can use postmarketing requirements to mandate pharmaceutical companies to conduct clinical trials after the approval of novel therapeutics. Pharmaceutical companies can also agree to conduct nonmandated clinical trials as postmarketing commitments. However, when therapeutics are approved by the FDA without postmarketing requirements or postmarketing commitments, it is not well known how often pharmaceutical companies voluntarily conduct trials and report results monitoring safety or efficacy after approval. Objective: To characterize postapproval clinical trials sponsored by pharmaceutical companies of therapeutics initially approved by the FDA without clinical postmarketing requirements or commitments. Design, Setting, and Participants: This cross-sectional analysis included postapproval clinical trials conducted with at least 1 site in the United States sponsored by pharmaceutical companies of therapeutics first approved by the FDA from 2009 through 2012. Analyses were conducted June 11, 2018, to November 30, 2018. Main Outcomes and Measures: Postapproval clinical trials registered on ClinicalTrials.gov generating safety or efficacy data, characteristics including whether trials focused on approved or unapproved indications, study design elements, and rates of study completion and results reporting. Results: From 2009 through 2012, the FDA approved 110 novel therapeutics for 120 indications, of which 37 novel therapeutics for 39 indications did not have postmarketing requirements or commitments for new clinical studies at the time of first approval. For 31 therapeutics (83.8%), there were 600 postapproval clinical trials sponsored by pharmaceutical companies. Most trials investigated therapeutics for new indications (363 [60.5%]) or expanded populations of the originally indicated disease (122 [20.3%]). Trials were often small (median [interquartile range] enrollment, 44 [21-131] participants), nonrandomized (359 [59.8%]), unblinded (455 [75.8%]), and lacked comparators (381 [63.5%]). Approximately half of the trials (311 [51.8%]) assessed at least 1 clinical outcome. Of 300 terminated or completed trials, 204 trials (68.0%) had reported results on ClinicalTrials.gov a median (interquartile range) 16 (13-25) months after their primary completion date. For the 96 trials (32.0%) without reported results, a median (interquartile range) 35 (13-62) months had passed since their primary completion date. Conclusions and Relevance: Pharmaceutical companies frequently conducted clinical trials after approval, even when there were no clinical postmarketing requirements or commitments at approval. However, most of these trials evaluated new indications or expanded patient populations rather than monitored approved uses, and nearly half of the trials remained incomplete more than 5 years after original therapeutic approval.


Assuntos
Ensaios Clínicos como Assunto/estatística & dados numéricos , Aprovação de Drogas/estatística & dados numéricos , Vigilância de Produtos Comercializados/estatística & dados numéricos , Estudos Transversais , Indústria Farmacêutica/métodos , Humanos , Estados Unidos , United States Food and Drug Administration
15.
BMJ Open ; 9(3): e025936, 2019 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-30904868

RESUMO

OBJECTIVES: To collate and systematically characterise the methods, results and clinical performance of the clinical risk prediction submissions to the Systolic Blood Pressure Intervention Trial (SPRINT) Data Analysis Challenge. DESIGN: Cross-sectional evaluation. DATA SOURCES: SPRINT Challenge online submission website. STUDY SELECTION: Submissions to the SPRINT Challenge for clinical prediction tools or clinical risk scores. DATA EXTRACTION: In duplicate by three independent reviewers. RESULTS: Of 143 submissions, 29 met our inclusion criteria. Of these, 23/29 (79%) reported prediction models for an efficacy outcome (20/23 [87%] of these used the SPRINT study primary composite outcome, 14/29 [48%] used a safety outcome, and 4/29 [14%] examined a combined safety/efficacy outcome). Age and cardiovascular disease history were the most common variables retained in 80% (12/15) of the efficacy and 60% (6/10) of the safety models. However, no two submissions included an identical list of variables intending to predict the same outcomes. Model performance measures, most commonly, the C-statistic, were reported in 57% (13/23) of efficacy and 64% (9/14) of safety model submissions. Only 2/29 (7%) models reported external validation. Nine of 29 (31%) submissions developed and provided evaluable risk prediction tools. Using two hypothetical vignettes, 67% (6/9) of the tools provided expected recommendations for a low-risk patient, while 44% (4/9) did for a high-risk patient. Only 2/29 (7%) of the clinical risk prediction submissions have been published to date. CONCLUSIONS: Despite use of the same data source, a diversity of approaches, methods and results was produced by the 29 SPRINT Challenge competition submissions for clinical risk prediction. Of the nine evaluable risk prediction tools, clinical performance was suboptimal. By collating an overview of the range of approaches taken, researchers may further optimise the development of risk prediction tools in SPRINT-eligible populations, and our findings may inform the conduct of future similar open science projects.

17.
PLoS Biol ; 16(11): e2006930, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30457984

RESUMO

Currently, there is a growing interest in ensuring the transparency and reproducibility of the published scientific literature. According to a previous evaluation of 441 biomedical journals articles published in 2000-2014, the biomedical literature largely lacked transparency in important dimensions. Here, we surveyed a random sample of 149 biomedical articles published between 2015 and 2017 and determined the proportion reporting sources of public and/or private funding and conflicts of interests, sharing protocols and raw data, and undergoing rigorous independent replication and reproducibility checks. We also investigated what can be learned about reproducibility and transparency indicators from open access data provided on PubMed. The majority of the 149 studies disclosed some information regarding funding (103, 69.1% [95% confidence interval, 61.0% to 76.3%]) or conflicts of interest (97, 65.1% [56.8% to 72.6%]). Among the 104 articles with empirical data in which protocols or data sharing would be pertinent, 19 (18.3% [11.6% to 27.3%]) discussed publicly available data; only one (1.0% [0.1% to 6.0%]) included a link to a full study protocol. Among the 97 articles in which replication in studies with different data would be pertinent, there were five replication efforts (5.2% [1.9% to 12.2%]). Although clinical trial identification numbers and funding details were often provided on PubMed, only two of the articles without a full text article in PubMed Central that discussed publicly available data at the full text level also contained information related to data sharing on PubMed; none had a conflicts of interest statement on PubMed. Our evaluation suggests that although there have been improvements over the last few years in certain key indicators of reproducibility and transparency, opportunities exist to improve reproducible research practices across the biomedical literature and to make features related to reproducibility more readily visible in PubMed.


Assuntos
Pesquisa Biomédica/economia , Pesquisa Biomédica/ética , Acesso à Informação/ética , Conflito de Interesses/economia , Revelação/ética , Revelação/normas , Humanos , Disseminação de Informação/ética , Disseminação de Informação/métodos , Publicações/ética , Reprodutibilidade dos Testes
19.
Trials ; 19(1): 448, 2018 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-30134950

RESUMO

BACKGROUND: Registration of clinical trials is critical for promoting transparency and integrity in medical research; however, trials must be registered in a prospective fashion to deter unaccounted protocol modifications or selection of alternate outcomes that may enhance favorability of reported findings. We assessed adherence to the International Committee of Medical Journal Editors' (ICMJE) prospective registration policy and identified the frequency of registrations occurring after potential observation of primary outcome data among trials published in the highest-impact journals associated with US professional medical societies. Additionally, we examined whether trials that are unregistered or registered after potential observation of primary outcome data were more likely to report favorable findings. METHODS: We conducted a retrospective, cross-sectional analysis of the 50 most recently published clinical trials that reported primary results in each of the ten highest-impact US medical specialty society journals between 1 January 2010 and 31 December 2015. We used descriptive statistics to characterize the proportions of trials that were: registered; registered retrospectively; registered retrospectively potentially after initial ascertainment of primary outcomes; and reporting favorable findings, overall and stratified by journal and trial characteristics. Chi-squared analyses were performed to assess differences in registration by journal and trial characteristics. RESULTS: We reviewed 6869 original research reports published between 1 January 2010 and 31 December 2015 to identify a total of 486 trials across 472 publications. Of these 486 trials, 47 (10%) were unregistered. Among 439 registered trials, 340 (77%) were registered prospectively and 99 (23%) retrospectively. Sixty-seven (68%) of these 99 retrospectively registered trials, or 15% of all 439 registered trials, were registered after potential observation of primary outcome data ascertained among participants enrolled at inception. Industry-funded trials, those with enrollment sites in the US, as well as those assessing FDA-regulated interventions each had lower rates of retrospective registration. Unregistered trials were more likely to report favorable findings than were registered trials (89% vs. 64%; relative risk (RR) = 1.38, 95% confidence interval (CI) = 1.20-1.58; p = 0.004), irrespective of registration timing. CONCLUSIONS: Adherence to the ICMJE's prospective registration policy remains sub-standard, even in the highest-impact journals associated with US professional medical societies. These journals frequently published unregistered trials and trials registered after potential observation of primary outcome data.


Assuntos
Fidelidade a Diretrizes/normas , Guias como Assunto , Publicações Periódicas como Assunto/normas , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Projetos de Pesquisa/normas , Bibliometria , Estudos Transversais , Fidelidade a Diretrizes/tendências , Humanos , Fator de Impacto de Revistas , Publicações Periódicas como Assunto/tendências , Projetos de Pesquisa/tendências , Estudos Retrospectivos , Fatores de Tempo
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