Thiazide diuretics and the risk of gallbladder disease requiring surgery in women.

BACKGROUND Previous studies have suggested that thiazide diuretic use increases the risk of cholecystitis. METHODS We prospectively examined the association between thiazide use and cholecystectomy, a surrogate for symptomatic cholelithiasis, in a cohort of 81 351 US women who were aged 30 to 55 years in 1980 and followed up to 2000. Regular use of thiazide diuretics was assessed at baseline by asking the participants to report whether they currently took "any of the following medications in most weeks" and listing "thiazide diuretics (eg, Diuril and Hydrodiuril)" among other drugs. Respondents were also requested to report the duration of thiazide diuretic use. Assessment of thiazide diuretic use was updated in 1982, 1988, 1994, 1996, and 1998. Cox regression was used to adjust simultaneously for other potential risk factors for cholecystectomy. RESULTS During follow-up, 8607 women reported undergoing a cholecystectomy. A modest positive relation between the use of thiazide diuretics and cholecystectomy was observed. Compared with never users of thiazide diuretics, the multivariate relative risk of cholecystectomy for past users was 1.16 (95% confidence interval,1.08-1.24) and the multivariate relative risk for current users was 1.39 (95% confidence interval, 1.29-1.50). CONCLUSIONS These findings are compatible with the hypothesis that the use of thiazide diuretics increases the risk of symptomatic cholecystitis. However, we cannot rule out the possibility that our results are in part explained by unconsidered factors related to the indication for antihypertensive therapy or by differences in medical surveillance between users and nonusers of thiazide diuretics.