Predictors of Recurrent Urolithiasis in Iran: Findings from a Nationwide Study.

Background: Prevention of urinary stone recurrence is the ultimate goal in urolithiasis patients. In this study, we aimed to investigate the national prevalence rate and possible determinants of increased urolithiasis recurrence risk in a nationwide study in Iran.

Methods: All data regarding stone occurrence and recurrence episodes were extracted from the cross-sectional Iran National Stone Survey (INSS) study, and the possible determinants of recurrence were evaluated in the subset of 2913 patients who had a positive history of at least one episode of urolithiasis.

Results: The national prevalence rate of recurrent urolithiasis was 2.6% (95% CI: 2.5, 2.8) in Iran. Moreover, the relative ratio of recurrent stone formers to all stone formers was 39.8% (95% CI: 38.0, 41.6). Our univariable truncated negative binomial regressions suggested that a positive history of urolithiasis in the patient's father (prevalence ratio [PR] [95% CI]=1.83 [1.39, 2.41], <0.001), mother (PR [95% CI]=1.92 [1.39, 2.66], <0.001) or brother (PR [95% CI]=1.32 [1.03, 1.69], =0.026); and residence in urban areas (PR [95% CI]=1.27 [1.04, 1.55], =0.016) were significant predictors of repetitive recurrence episodes. However, when incorporated into a multivariable truncated negative binomial regression model, the only significant predictors of more frequent recurrence episodes were a positive history in father (PR [95% CI]=1.66 [1.24, 2.22], <0.001) and mother (PR [95% CI]=1.68 [1.20, 2.36], =0.002); and urban residence (PR [95% CI]=1.24 [1.01, 1.51], =0.031).

Conclusion: Our results indicate that a positive family history of urolithiasis in mother and father and residence in urban areas are the significant predictors of recurrence risk in urolithiasis patients in Iran.