Trials on trial. A review of trials of antibiotic prophylaxis.

The ability of a small-scale random-control clinical trial comprising less than 500 patients to disclose clinically important differences between treatment groups depends on the event rate in the control group. The high rate of wound infection after abdominal operations has attracted many trials of methods of antibiotic prophylaxis. We reviewed all of the pertinent English literature recorded in Index Medicus in 1980 and 1981. We examined 45 articles for defects in design, analysis, and presentation. Of the 45 articles, 25 reported statistically significant differences between treatment groups and 20, no significant differences. Unsatisfactory methods of randomization were used in four trials, ethics were questionable in 22, statistical methods were incorrect in 31, and presentation was inadequate in 40. We concluded that there is room for improvement in the conduct of clinical trials.