Thiazide Diuretic Dose and Risk of Kidney Stones in Older Adults: A Retrospective Cohort Study.

Background Thiazide diuretics are commonly prescribed to prevent kidney stones. However, it is unclear whether higher doses confer greater benefit. Objective To determine whether lower doses of thiazide diuretics confer a similar protective effect against kidney stone events as higher doses. Design Population-based cohort study. Setting Linked health administrative databases in Ontario, Canada. Patients Older adults newly prescribed a thiazide diuretic between 2003 and 2014 were separated into 2 groups based on daily dose: low dose (⩽12.5 mg hydrochlorothiazide/chlorthalidone, or ⩽1.25 mg indapamide) or high dose. Measurements The primary outcome was time to a kidney stone event, using diagnosis and procedure codes. A secondary outcome was kidney stone surgery. Methods An association between thiazide diuretic dose and a kidney stone event was estimated using Cox proportional hazards regression. Results A total of 536 of 105 239 patients (0.51%) experienced a kidney stone event. We did not detect a difference in kidney stone risk in the high-dose relative to the low-dose group (adjusted hazard ratio, 1.10; 95% confidence interval, 0.93-1.31). Results were similar when analysis was restricted to the more specific outcome of kidney stone surgery. Neither a history of prior kidney stones nor the type of thiazide diuretic modified the effect of diuretic dose on outcome. Limitations Patients were >65 years old and we were unable to adjust for some potential confounders such as dietary factors. Conclusions Lower dose thiazide diuretics appear to confer a similar protective effect as higher dose thiazides against the development of kidney stones

supplemental_material-_R1Black – Supplemental material for Thiazide Diuretic Dose and Risk of Kidney Stones in Older Adults: A Retrospective Cohort Study

<p>Supplemental material, supplemental_material-_R1Black for Thiazide Diuretic Dose and Risk of Kidney Stones in Older Adults: A Retrospective Cohort Study by R. Todd Alexander, Eric McArthur, Racquel Jandoc, Blayne Welk, Daniel G. Fuster, Amit X. Garg and Robert R. Quinn in Canadian Journal of Kidney Health and Disease</p