Incidence of Kidney Stones After Bariatric Surgeries: Comparing Roux-en-Y Gastric Bypass and Sleeve Gastrectomy.

Introduction/purpose: The two most common procedures performed to treat obesity are Roux-En-Y gastric bypass (RNYGB) and laparoscopic sleeve gastrectomy (LSG). Due to changes in enteric absorption, bariatric surgery increases rates of nephrolithiasis. As population-based data are limited, we aimed to compare the incidence of kidney stones after RNYGB and LSG.

Materials And Methods: We queried Explorys (Cleveland, OH), a database that aggregated data from 26 healthcare systems. We identified patients who were newly diagnosed with nephrolithiasis 3, 6, and 12 months after their RNYGB or LSG. Additionally, a multivariate analysis was conducted to investigate the association of nephrolithiasis with RNYGB as compared to LSG. This analysis adjusted for other risk factors, including age above 65, male gender, Caucasian race, diabetes mellitus, hypertension, primary hyperparathyroidism, gout, and obesity.

Results: From 1999 to 2019, there were 11,480 patients who underwent RNYGB and 22,770 patients who underwent LSG. The incidence of nephrolithiasis in the RNYGB cohort at all three time points was higher than in the LSG cohort (3 months, 7.1% vs. 2.4%; 6 months, 6.6% vs. 2.0%; 1 year, 5.8% vs. 1.4%; P < 0.001). After the multivariate analysis, it was found that, though both RNYGB and LSG were independently associated with the development of nephrolithiasis, the risk of nephrolithiasis was higher in those who underwent RNYGB compared to those who underwent LSG (OR 1.594, 95% CI 1.494 to 1.701, P < 0.001).

Conclusion: RNYGB is associated with a higher risk of nephrolithiasis when compared to LSG.