Risk of urinary stone formation associated to proton pump inhibitors: a systematic review and metanalysis

Objective: Proton pump inhibitors are widely used as treatment of acid-related disorders. They are considered safe although their long-term use has been associated with some adverse effects including an increased propensity for urinary calculi formation. The aim of this study was to systematically review available data from studies evaluating the association of PPIs and nephrolithiasis. Materials and methods: We searched two electronic databases (PubMed and EMBASE) for cohort studies or case-control studies evaluating the relationship between treatment with proton pump inhibitors and the risk of stone formation published up to 31 October 2022. The overall association of PPIs and urinary calculi was analyzed using a random effects model (RevMan5). The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. Results: A total of 550 studies were retrieved; 7 were selected by title and abstract screening; after removal of duplicates, 4 records were evaluated by full-text examination. An additional study was retrieved by handsearching the references included in screened studies. In the unadjusted analysis, the odds of urinary calculi were greater in subjects taking PPIs compared to controls (unadjusted OR = 2.10, 95% CI 1.74-2.52, p < 0.00001). The pooled odds ratio of two case-control studies confirmed that use of PPIs increased the odds of urinary calculi compared with non-use (OR 2.44, 95% CI 2.29 to 2.61). Pooled analysis of three cohort studies evaluating incident nephrolithiasis showed an overall hazard ratio estimate of 1.34 (95% CI = 1.28-1.40). One study found lower urinary citrate and urinary magnesium levels in subjects exposed to PPIs. The Newcastle-Ottawa Quality Assessment Scale scores ranged between 6 and 8. Conclusions: PPIs showed an association with urinary calculi in patients included in the studies included in this review. If these data will be confirmed in adequately powered randomized trials, clinicians may consider limiting the long-term use of PPIs, to avoid unnecessary prolongation of treatment. Urinary magnesium and citrate should be evaluated in renal stone forming patients taking PPIs to supplement their intake when requested.