Source of funding and outcome of clinical trials.

Because of recent concerns about conflicts of interest and published research, the author analyzed 107 controlled clinical trials. Studies were classified as favoring either a new therapy or a traditional therapy, and as being supported by a pharmaceutical manufacturer or as being generally supported. Seventy-one per cent of the trials favored new therapies; 43% of these were funded by pharmaceutical firms. Of the 31 trials favoring traditional therapy, only four (13%) were supported by a pharmaceutical firm. There was a statistically significant association between the source of funding and the outcome of the study (p = 0.002). Few trials supported by pharmaceutical manufacturers favored traditional therapy; some reasons for this finding may include selection of drugs likely to be proven efficacious, Type II errors (false-negative studies), and fear of discontinuation of funding should such studies be submitted. Important clinical information may be lost if negative studies are not published.