Thiazide diuretics, alkali therapy help reduce symptomatic stone events

Adherence to thiazide diuretics among patients with urolithiasis and hypercalciuria leads to fewer symptomatic stone events, as does adherence to alkali therapy among those with low urine pH, according to a retrospective cohort study.

Researchers reviewed the medical records of Medicare enrolees with urolithiasis who had 24-hour urine findings that showed hypercalciuria, hypocitraturia, low urine pH, or hyperuricosuria. The participants were grouped into three based on the use of preventive pharmacological therapy (PPT)—such as thiazide diuretics for hypercalciuria, alkali for hypocitraturia or low urine pH, or uric acid lowering drugs for hyperuricosuria—as follows: adherent, nonadherent, or untreated.

The analysis included 13,942 participants, of which 31.0 percent had received prescription for PPT. Compared with no treatment, PPT adherence was associated with a significantly lower risk of symptomatic stone events among patients with hypercalciuria (hazard ratio [HR], 0.736, 95 percent confidence interval [CI], 0.593–0.915) and low urine pH (HR, 0.804, 95 percent CI, 0.650–0.996) but not among patients with hypocitraturia or hyperuricosuria. The link between PPT and positive outcomes was largely driven by a substantial reduction in ED visits within the adherent group.

The adjusted 2-year predicted probabilities of an emergency department visit was 3.8 percent (95 percent CI, 2.5–5.2) within the adherent group and 6.9 percent (95 percent CI, 6.0–7.7) within the untreated group for patients with hypercalciuria, and 4.3 percent (95 percent CI, 2.9–5.7) and 7.3 percent (95 percent CI, 6.5–8.0), respectively, for patients with low urine pH.

The study was limited by potential bias from the possibility that patients prescribed PPT had more severe disease than untreated patients.