Context The evaluation of the methodologic quality of randomized controlled
trials (RCTs) is central to evidence-based health care. Important methodologic
detail may, however, be omitted from published reports, and the quality of
reporting is therefore often used as a proxy measure for methodologic quality.
We examined the relationship between reporting quality and methodologic quality
of published RCTs.
Methods Study of 60 reports of placebo-controlled trials published in English-language
journals from 1985 to 1997. Reporting quality was measured using a 25-item
scale based on the 1996 issue of the Consolidated Standards of Reporting Trials
(CONSORT). Concealment of allocation, appropriate blinding, and analysis according
to the intention-to-treat principle were indicators of methodologic quality.
Methodologic quality was compared between groups of trials defined by reporting
quality scores of low, intermediate, and high. Reporting quality scores were
compared between groups defined by high and low methodologic quality.
Results Among 23 trials of low reporting quality (median score, 9 [range, 3.5-10.5]),
allocation concealment was unclear for all but 1 trial, but there were 16
trials (70%) with adequate blinding and 9 trials (39%) that had been analyzed
according to the intention-to-treat principle. Among 18 trials of high reporting
quality (median score, 18 [range 16.5-22.0]), there were 8 trials (44%) with
adequate allocation concealment, 16 trials (89%) with adequate blinding, and
13 trials (72%) analyzed according to the intention-to-treat principle. The
median reporting score was 15.0 for the 33 trials that were analyzed according
to intention-to-treat principle and 14.5 for the 14 trials with on-treatment
analyses (P = .67).
Conclusions Similar quality of reporting may hide important differences in methodologic
quality, and well-conducted trials may be reported badly. A clear distinction
should be made between these 2 dimensions of the quality of RCTs.