Thiazides and acute cholecystitis.

An association between acute cholecystitis and the use of thiazide-containing drugs was observed during routine screening of data from a case-control drug-surveillance program. Evaluation of this relation among 419 patients with acute cholecystitis and 1676 control patients yielded a relative risk estimate of 2.0 for subjects who had used thiazides in the month before admission, as compared with subjects who had never used these drugs (95 per cent confidence interval, 1.4 to 2.7). There was a significant trend of increasing relative risk with increasing duration of use (P < 0.01), and the estimate for subjects who had used thiazides for five or more years was 2.9. The association was not explained by confounding due to the indications for thiazide use, such as hypertension, or other factors, such as obesity or the use of other drugs. No single epidemiologic study can eliminate chance or bias as an explanation for an association; the relation found here should be regarded as a hypothesis that requires independent confirmation.