Physician-authored summaries and commentary on the most important medical research, provided by the NEJM Group, a division of the Massachusetts Medical Society.
© Massachusetts Medical SocietyApril 2023
In a randomised trial, thiazides, compared with placebo, did not prevent symptomatic stone events.
Thiazide diuretics have long been recommended to decrease recurrent nephrolithiasis in people with calcium stones, based on observational data and small randomised trials. To provide more robust evidence, Swiss researchers randomised 416 adults with at least two previous symptomatic calcium stone events to receive hydrochlorothiazide (at doses of 12.5 mg, 25 mg or 50 mg daily) or placebo. People with secondary causes of stones (e.g. hyperparathyroidism) were excluded, but those with idiopathic hypercalciuria were permitted to enrol.
The primary composite endpoint consisted of both symptomatic stone events and presence of a new stone or enlargement of a pre-existing stone on renal computed tomography (scans were done at baseline and at end of study). During three years of follow up, no significant difference was noted in the incidence of this composite endpoint – or the incidence of symptomatic stones – for any thiazide-dose group compared with the placebo group. However, those who received 25 mg or 50 mg of hydrochlorothiazide, compared with placebo recipients, had a significantly lower incidence of asymptomatic radiological recurrent stones (33% vs 49%).
Comment: It is unclear why these largely negative results are not consistent with findings from previous studies. Although this study will dampen enthusiasm for thiazides in people with recurrent calcium nephrolithiasis, an editorialist – an expert in nephrolithiasis – is not quite ready to abandon them totally. For example, the finding of fewer asymptomatic stones with thiazides might translate into fewer symptomatic episodes with longer follow up. For now, a compromise might be to use thiazides for stone prevention mainly in people with another indication for thiazides – hypertension, for example.
Allan S. Brett, MD
Clinical Professor of Medicine, University of Colorado School of Medicine, Aurora, USA.
Dhayat NA, et al. Hydrochlorothiazide and prevention of kidney-stone recurrence. N Engl J Med 2023; 388: 781-791.
Alexander RT. Do thiazides reduce the risk of kidney-stone recurrence? N Engl J Med 2023; 388: 841-842.
This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine