Venous thromboembolic disease and combined oral contraceptives: A re-analysis of the MediPlus database

In October 1995 the Committee on Safety of Medicines advised UK doctors and pharmacists that oral contraceptives containing desogestrel and gestodene were associated with double the risk of venous thromboembolic events (VTE) compared to pills containing other progestogens. In 1997 data was analysed from the MediPlus database of UK general practitioner records, which report ed odds ratios for desogestrel and gestodene lower than that for levonorges trel. Here the results of a more stringent nested case control analysis on the MediPlus database are reported, The study was larger and cases were ver ified. A crude incidence of idiopathic VTE was found amongst users of combi ned oral contraceptives of 4.6 per 10 000 exposed women years. Using levono rgestrel 150 mu g + ethinyloestradiol 30 mu g as reference, non-significant odds ratios of 1.1 (0.5-2.6) for desogestrel 150 mu g + ethinyloestradiol 30 mu g and 1.1 (0.5-2.4) for gestodene 75 mu g + ethinyloestradiol 30 mu g were found. The results of this study show no significant difference in ri sk between different formulations of combined oral contraceptive.