Meta-analysis of randomized trials for medical prevention of calcium oxalate nephrolithiasis

Objectives: To determine the efficacy of commonly used medications in compa rison with placebo or no treatment for the prevention of renal stone recurr ence (metaphylaxis) as documented in the literature, Methods: A MEDLINE search identified 14 randomized, controlled trials compr ising 20 treatment arms and 6 different drug therapies for the prevention o f stone recurrence. The active treatment arms from each of the trials were combined, and the results were compared with those of the control or no tre atment arms overall and for each category of drug therapy (thiazide diureti cs, allopurinol, phosphate, magnesium, and alkali citrate), A meta-analysis was performed of the combined treatment and control arms for all trials fr om which sufficient data were provided, both for overall medical therapy an d for thiazide treatment. Results: A statistically significant benefit of drug therapy for stone meta phylaxis was identified (P = 0,04), largely because of the benefit of thiaz ides compared with placebo or no treatment (P = 0.02), Allopurinol conferre d no overall benefit, although the only trial evaluating therapy in hyperur icosuric patients showed a statistically significant benefit. Conclusion: Medical therapy for calcium stone disease reduces the incidence of recurrence. Although only thiazide diuretics among the drug therapies w ere shown to significantly reduce stone recurrence, variability in study de sign and study population precluded adequate analysis of other drug therapi es such as alkali citrate. Standardization of study design and reporting sh ould improve the evaluation of the efficacy of new drug treatments.