We compared the efficacy of diclofenac potassium in unpublished clinical study reports (CSRs) and published reports to examine\npublication bias, industry bias, and comprehensiveness. Novartis provided CSRs of randomised double-blind trials of diclofenac\npotassium involving postoperative patients following third molar extraction (3 trials, n 519), gynaecological surgery (3 trials,\nn 679), and dysmenorrhoea (2 trials, n 711) conducted in 1988ââ?¬â??1990. Searches identified published reports of 6 trials.\nInformation from 599/1909 patients was not published; trials with 846/1909 patients were published in a defunct journal. Greater\nmethodological information in CSRs contributed to lesser risk of bias than published trials. Numbers needed to treat (NNT) from\nCSRs for all six postoperative trials for at least 50% of maximum pain relief over 6 h were 2.2 (95% confidence interval, 1.9ââ?¬â??2.6) and\n2.1 (1.8ââ?¬â??2.4) for 50 and 100mg diclofenac potassium, respectively. A Cochrane review of published trial data reported NNTs of 2.1\nand 1.9, and one comprehensive analysis reported NNTs of 2.2 and 2.1, respectively. All analyses had similar results for patients\nremedicating within 8 h.No data from dysmenorrhoea CSRs appeared in a Cochrane review. CSRs provide useful information and\nincrease confidence. Stable efficacy estimates with standard study designs reduce the need for updating reviews.
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