Arrabal-Martín M et al. (2006) Extracorporeal renal lithotripsy: evolution of residual lithiasis treated with thiazides. Urology 68: 956–959

Nephrolithiasis can persist after treatment with extracorporeal shock-wave lithotripsy (ESWL). Thiazide diuretics reduce the renal excretion of calcium and have been used to treat calcium nephrolithiasis with hypercalciuria; however, concerns remain over the long-term efficacy and adverse effects of thiazide diuretics in this setting. Arrabal-Martín et al. analyzed the evolution of residual nephrolithiasis after ESWL, and evaluated the long-term use of thiazide diuretics in the treatment of nephrolithiasis.

This longitudinal study included 100 patients who presented with residual nephrolithiasis 3 months after ESWL. Patients were randomly allocated to receive either placebo (n = 50) or 50 mg hydrochlorothiazide (n = 50) daily for 36 months, and were evaluated every 6 months by radiography of the urinary tract, and annually by urinary metabolic studies. Renal ultrasonography was carried out at baseline and study end.

The total expulsion of calculus fragments in the thiazide-treated group was significantly greater than in the placebo-treated group (P <0.001). Markedly more placebo-treated than thiazide-treated patients required at least one additional ESWL procedure (42% versus 18%). The incidence of hypercalciuria was similar in both groups, but expulsion of calculus fragments was greater in the thiazide-treated group than in the placebo-treated group (P = 0.001). Thiazide diuretic treatment reduced or maintained the size of residual fragments in patients with hypercalciuria; this effect was not observed in placebo-treated patients.

The authors conclude that thiazide administration arrested nephrolithiasis, which favored the spontaneous elimination of residual calculus fragments and reduced the need for additional ESWL procedures.