Potassium citrate for stone prevention - Quantifying benefit through the number needed to treat: A narrative review.

Abstract

To define how reliable the benefits of potassium citrate (KCit) for stone prevention are framing this in terms of the number needed to treat (NNT). A targeted search of PubMed/MEDLINE, Embase, and the Cochrane Library was conducted through January 2025. For studies reporting recurrence rates in treatment and control groups, absolute risk reduction (ARR) and NNT were calculated. Two pivotal randomized trials in recurrent calcium stone formers demonstrated large ARRs with KCit or potassium-magnesium citrate, lowering 3-year recurrence rates from approximately 60%-80% in placebo groups to 10%-30% with therapy. Corresponding ARRs were around 50%, yielding NNTs of approximately 2 over 3 years. Evidence is strongest for calcium oxalate disease; data for calcium phosphate and brushite stones remain limited. In uric acid and cystine stones, alkalinization is first-line therapy, although precise NNT estimates are unavailable. KCit is one of the most effective preventive pharmacotherapies in nephrolithiasis. In recurrent calcium stone formers, treating two to three patients for approximately 3 years prevents one recurrence, representing a highly favorable benefit-risk profile when appropriately monitored and individualized by stone phenotype.