COMPREHENSIVENESS AND BIAS IN REPORTING CLINICAL-TRIALS - STUDY OF REVIEWS OF PNEUMOCOCCAL VACCINE EFFECTIVENESS

PURPOSE To assess the extent to which relevant controlled clinical tri als are cited and summarized in review articles, and to determine whet her citation of relevant clinical trials is biased as to study results . DATA SOURCES Articles were identified by searching MEDLINE and EMBAS E databases. STUDY SECTION Review articles published between 1986 and 1988 on the clinical effectiveness of pneumococcal vaccine. DATA EXTRA CTION Proportion of relevant clinical trials cited and whether citatio n is biased by study results. DATA SYNTHESIS The proportion of relevan t primary studies cited per review article ranged from 0% to 36% (mean 9%). The number of trials cited per review ranged from zero to six (m ean 1.2). In nine of 17 reviews, no clinical trials were cited. Study populations and outcome(s) were specified and results presented quanti tatively for 0 to 27% of relevant trials per review (mean 6%). Unsuppo rtive trials were almost twice as likely to be cited as supportive tri als. CONCLUSIONS Reporting of the results of relevant clinical trials in reviews of pneumococcal vaccine effectiveness is incomplete. Our fi ndings suggest a need for greater scientific rigour in preparing revie wing, and editing review articles.