The Association Between 24-Hour Urine and Stone Recurrence Among High Risk Kidney Stone Formers: A Population Level Assessment.

Abstract Objectives To determine if obtaining a 24-hour urine collection (24HU) in stone formers is associated with decreased recurrent stone episodes. Methods Using the MarketScan® database, adults 17-62 years old with nephrolithiasis were identified between 2007-2017 with a minimum of 3 years follow up. High-risk stone formers, those undergoing stone surgery, and those with history of recurrent stones were identified. The exposure was a 24HU within 6 months of primary diagnosis. The outcome was recurrent stone episodes—defined by stone-related emergency room visits, hospitalizations, or stone surgery 90 days to 3 years after diagnosis. Logistic regression was used to estimate recurrence risk by 24HU exposure for the overall cohort and sub-cohorts limited to known recurrent stone formers, high-risk subjects, and those having stone surgery. Results Of 434,055 subjects analyzed, 30,153 (6.9%) had a 24HU. An annual decline in 24HU utilization was seen (7.5% to 5.8%). Regional variation in usage rate was also observed. On multivariate analysis, completing a 24HU was not associated with risk of recurrence in any of the following cohorts: recurrent stone formers (OR 0.98, 95% CI 0.9-1.07), both high risk and recurrent stone formers (OR 0.95 [0.8-1.13]), those undergoing surgery (OR 1.02 [0.97-1.07]); a positive association with 24HU and recurrence was seen in those labeled high-risk (OR 1.08 [1.01-1.16]) and in all-comers (OR 1.15 [1.12-1.19]). Conclusion 24HU was not associated with decreased recurrence rates in the overall population nor in higher risk sub-cohorts.