INCIDENCE OF KIDNEY STONES AFTER BARIATRIC SURGERIES: COMPARING ROUX-EN-Y GASTRIC BYPASS AND SLEEVE GASTRECTOMY
Raj Shah, Kyle Hoffman*, mayada ismail, Sagarika Satyavada, Gregory S. Cooper
Internal Medicine, University Hospitals Cleveland Medical Center,, Cleveland, OH
Introduction: Obesity rates continue to rise and thus more patients will be offered interventions to treat this widespread disease. The two most common procedures performed to treat obesity include Roux-En-Y gastric bypass (RNY) and sleeve gastrectomy (SG). Due to changes in enteric absorption, bariatric surgery increases urinary oxalate thereby increasing rates of nephrolithiasis. Patients and providers should be aware of the possible risk of each surgery to better inform their decision making, monitor symptoms post-operatively, and implement prophylactic measures. As national level population-based data are limited, we aimed to compare the incidence of kidney stones after RNY and SG.
Methods: We queried Explorys (Cleveland, OH), a commercial database that aggregated data from 26 integrated healthcare systems from 1999 to 2019. Two cohorts of patients who underwent either a "laparoscopic sleeve gastrectomy" or "Roux-En-Y gastrojejunostomy" were identified using Systematized Nomenclature of Medicine - Clinical Terms (SNOMED-CT). We identified patients who were newly diagnosed with "kidney stone" after 3, 6, and 12 months of their RNY or SG. Using 95% confidence intervals (CI), we calculated relative risks.
Results: From 1999 to 2019, there were 11,480 patients who underwent Roux-En-Y gastric bypass and 22,770 patients who underwent laparoscopic sleeve gastrectomy. Baseline characteristics of patients at 3 months post-operatively are outlined in Table 1. Nephrolithiasis at least three months after undergoing bariatric surgery occurred in 810 patients in the RYN group and 540 in the SG group (RR=2.9; 95% CI 2.67 to 3.31). After six months post-operatively, nephrolithiasis occurred in 760 patients in the RYN group and 460 in the SG group (RR=3.3; 95% CI 2.93- to 3.67). After one year after bariatric surgery, the incidence of nephrolithiasis was 670 patients in the RYN group and 320 patients in the SG group (RR=4.1; 95% CI 3.64-4.74). The incidence of nephrolithiasis in the RNY cohort at all three time points was higher than in the SG cohort (P <0.001) (Figure 1). Additionally, the incidence of nephrolithiasis decreased over time from the time of surgery.
Discussion: Patients undergoing RNY should be informed that the risk of nephrolithiasis is markedly higher than those undergoing SG. SG may be a preferred operation in those who patients who already have a predilection to getting kidney stones. Additionally, the risk seems to decrease with time post-operatively. Prophylactic measures implemented immediately in the post-operative time period such as dietary interventions to decrease the risk of calcium oxalate kidney stones should be further studied.
Demographic comparison of those with nephrolithiasis after Roux-En-Y gastrojejunostomy (RNY) or laparoscopic sleeve gastrectomy (SG) at 3 months to those who underwent SG or RNY without any diagnosis of nephrolithiasis.
Incidence of Post-operative Nephrolithiasis: laparoscopic sleeve gastrectomy (SG) vs. Roux-En-Y gastrojejunostomy (RNY)
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