Empiric Thiazides Associated With Lower Odds of Stone-Related Events in Urinary Stone Disease

Thiazide diuretics, when used as empiric initial pharmacologic therapy, may be associated with lower odds of stone-related events in patients with urinary stone disease, according to a study presented by Ryan Hsi, MD, of Vanderbilt University Medical Center in Nashville, at the 2021 American Urological Association Annual Meeting. Based on these findings, the researchers suggest thiazides could be considered as initial empiric pharmacologic therapy in cases when 24-hour urine testing is unavailable.

Recent data show similar rates of stone recurrence among patients with urinary stone disease who do versus don’t undergo 24-hour urine testing before the initiation of preventative pharmacologic therapy. As such, some experts indicate for an empiric approach, but few studies have determined the superiority of certain pharmacologic therapy medication subclasses over others in this context.

To investigate this gap in research, Dr. Hsi and colleagues compared stone-related event frequencies among patients who were empirically prescribed either thiazides (n=1,819), alkali citrate (n=639), allopurinol (n=550), or combination therapy (n= 203) without prior 24-hour urine testing. In the study, the investigators relied on medical claims data for working-age adults with urinary stone disease who filled a prescription for these agents between 2008 and 2017. All participants had at least three years’ worth of follow-up data available for analysis.

Multivariable regression analyses were used to estimate the relationship between pharmacologic therapy medication subclass and the incidence of the stone-related events, defined as either an emergency department visit, hospitalization, or surgery.

In the analysis adjusted for certain patient factors (eg, medication adherence and concomitant conditions associated with increased risk of recurrence), the investigators found an association between thiazide treatment and lower odds of a stone-related event when compared with allopurinol use (odds ratio=0.68; 95% CI, 0.52-0.88). In contrast, there was no significant association between alkali citrate therapy versus allopurinol or combination therapy versus thiazide for lower odds of a stone-related event.

Overall, the researchers reported that the predicted probability of a stone-related event in patients who received treatment with a thiazide was six percentage points higher than the predicted probability for patients prescribed alkali citrate and six percentage points lower than the predicted probability for patients prescribed allopurinol at the three-year follow-up period.