PURPOSE

We assessed the effects of thiazide treatment on urine oxalate excretion in patients with kidney stones.

MATERIALS AND METHODS

Of 537 patients (231 women), 209 (81 women) received thiazide for stone prevention. Urine oxalate was measured in 3, 24-hour urines before treatment, and in 1, 24-hour urine after 6 to 12 weeks of treatment. This was an observational cohort and treatment was not randomized.

RESULTS

Urine oxalate increased in general. There was no difference in increase with or without thiazide, whether one considered simple t test comparisons or used ANOVA with pretreatment oxalate excretion as a covariate.

CONCLUSIONS

Thiazide administration exerts no measurable effect on urine oxalate excretion that can be detected in clinical practice.