For a study, researchers sought to compare how often individuals using thiazides, alkali citrate, and allopurinol experience stone-related events without first undergoing a 24-hour urine test. When given empirically, it was uncertain if 1 type of preventive pharmaceutical therapy (PPT) drugs were more advantageous for lowering kidney stone recurrence.

They identified those given thiazides, alkali citrate, or allopurinol using medical claims data from working-age persons with kidney stone diagnoses (2008-2018). Unfortunately, they didn’t include anyone who had had 24-hour urine testing or had fewer than three years of follow-up after starting PPT. To determine the relationship between the occurrence of a stone-related event (emergency department visit, hospitalization, or surgery for stones) and the PPT drug type, they fitted multivariable regression models.

The group included patients who were experimentally administered thiazides, alkali citrate, or allopurinol, respectively, and included 1,834 (60%), 654 (21%), and 558 (18%) individuals. The adjusted rate of any stone occurrence was lowest for the thiazide group (14.8%) compared to alkali citrate (20.4%) or allopurinol (20.4%) groups when patient characteristics such as medication adherence and concurrent conditions that enhance the risk of recurrence were taken into account (each P<.001). In comparison to allopurinol, thiazides were linked to a 32% decreased risk of a future stone incident by 3 years (OR 0.68, 95% CI 0.53-0.88). Alkali citrate and allopurinol were compared, and no such connection was found (OR 1.00, 95% CI 0.75-1.34).

The likelihood of further stone-related incidents was greatly reduced when empiric PPT was used with thiazides. Thiazides may be recommended over alkali citrate or allopurinol for empiric PPT when 24-hour urine testing is unavailable.