当前位置： SCI文献检索 > BMJ-British Medical Journal期刊下所有文献 > Practices and impact of primary outcome adjustment in randomized controlled trials: meta-epidemiologic study.

Practices and impact of primary outcome adjustment in randomized controlled trials: meta-epidemiologic study.

Abstract：

OBJECTIVE:To assess adjustment practices for primary outcomes of randomized controlled trials and their impact on the results. DESIGN:Meta-epidemiologic study. DATA SOURCES:25 biomedical journals with the highest impact factor according to Journal Citation Reports 2009. STUDY SELECTION:Randomized controlled trials published in print in 2009 that reported primary outcomes. The search yielded 684 eligible papers of randomized controlled trials, of which 200 were randomly selected. DATA EXTRACTION:Two researchers independently extracted data on study population, intervention, primary outcome, and the adjustment plan for primary outcomes. They also recorded the magnitude and statistical significance of the intervention effect with and without adjustments, and estimated whether adjustment made a difference in the level of nominal significance. They also compared the analysis plan for model adjustment in the published trial versus the trial protocol with information on the protocol collected from registries, design papers, and communication with all corresponding authors. RESULTS:54% of the trials used stratified randomization, 96% presented baseline characteristics in the compared arms, and 46% also evaluated differences in baseline factors with statistical testing. Half of the trials performed adjusted analyses for the main outcome, as the sole analysis (29%) or along with unadjusted analyses (21%). Adjustment for stratification variables and for baseline variables was performed in 39% (42/108) and 42% (84/199) of the trials, respectively. Among 40 comparisons with both adjusted and unadjusted analyses, 43% had statistically significant effects, 40% had non-significant effects, and 18% had significant effects with only one of the two analyses, but not with the other. Information on analysis plan regarding model adjustment was available in 6% (9/162) of trial registry entries, 78% (21/27) of design papers, and 74% (40/54) of protocols obtained from authors. The analysis plan disagreed between the published trial and the registry, protocol, or design paper in 47% (28/60) of the studies. CONCLUSIONS:There is large diversity on whether and how analyses of primary outcomes are adjusted in randomized controlled trials and these choices can sometimes change the nominal significance of the results. Registered protocols should explicitly specify adjustments plans for main outcomes and analysis should follow these plans.

journal_name

BMJ

journal_title

BMJ (Clinical research ed.)

authors

Saquib N,Saquib J,Ioannidis JP

doi

10.1136/bmj.f4313

subject

Has Abstract

pub_date

2013-07-12 00:00:00

pages

f4313

eissn

0959-8138

issn

1756-1833

journal_volume

347

pub_type

杂志文章,meta分析,评审

在线工具

Practices and impact of primary outcome adjustment in randomized controlled trials: meta-epidemiologic study.