Systematic review to determine whether participation in a trial influences outcome.

ABSTRACT:

Objective

To systematically compare the outcomes of participants in randomised controlled trials (RCTs) with those in comparable non-participants who received the same or similar treatment.

Data sources

Bibliographic databases, reference lists from eligible articles, medical journals, and study authors.

Review methods

RCTs and cohort studies that evaluated the clinical outcomes of participants in RCTs and comparable non-participants who received the same or similar treatment.

Results

Five RCTs (six comparisons) and 50 cohort studies (85 comparisons) provided data on 31,140 patients treated in RCTs and 20,380 comparable patients treated outside RCTs. In the five RCTs, in which patients were given the option of participating or not, the comparisons provided limit

SUBMITTER: Vist GE 

PROVIDER: S-EPMC558011 | biostudies-literature | 2005 May

REPOSITORIES: biostudies-literature