Category: Clinical Stones: Outcomes
Introduction & Objective :
Hyperoxaluria and nephrolithiasis are common after malabsorptive bariatric surgery; however, the comparative risk of nephrolithiasis and stone procedures after different bariatric surgeries remains unknown. In this study, we seek to compare risk of stone diagnosis and stone procedure after gastric banding, sleeve gastrectomy, short-limb Roux-en-Y (Roux SL), long-limb Roux-en-Y (Roux LL), and biliopancreatic diversion with duodenal switch (BPDDS).
Using the 2006-2014 Truven MarketScan® Commercial Claims and Encounters database we identified 116,304 patients that received bariatric surgery and were enrolled in the database for at least one year before and after their bariatric procedure. We used ICD-9-CM diagnosis codes to identify comorbidities and new stone diagnoses. We used CPT codes to identify bariatric procedures and stone removal procedures. Analysis was performed with a Cox proportional hazard’s model using all follow-up data.
Incidence of new stone diagnosis per 100 persons years was 1.3, 1.9, 2.6, 2.6, and 6.3 for gastric banding, sleeve gastrectomy, Roux SL, Roux LL, and BPDDS. While controlling for multiple confounders and using gastric banding as the reference, we found that BPDDS was associated with the greatest hazard of new stone diagnosis (HR 4.43, 95% CI 3.65-5.38), followed by Roux-en-Y (Roux SL, HR 1.93, 95% CI 1.82-2.04), then sleeve gastrectomy (HR 1.23, 95% CI 1.14-1.32). No significant difference in risk of stone diagnosis was observed between Roux LL and Roux SL. Similar differences and trends were observed in risk of stone procedure.
BPPDS is associated with greater risk of stone formation and stone procedures than Roux-en-Y which is associated with a greater risk than restrictive procedures. Nephrolithiasis is more common after more malabsorptive bariatric surgeries, especially in male patients.
Steven Monda– St Louis, Missouri
Joel Vetter– Statistician, Washington University in St. Louis, Saint Louis, Missouri
Margaret Olsen– St. Louis, Missouri
Matthew Keller– St. Louis, Missouri
Michael Chevinsky– Saint Louis, Missouri
Vasian Markollari– St. Louis, Missouri
Ramakrishna Venkatesh– Professor, Washington University in St. Louis, Saint Louis, Missouri
Alana Desai– Saint Louis, Missouri
St Louis, Missouri
Steven Monda is a fourth year medical student at Saint Louis University. He performs urological research at Washington University in St. Louis where he completed his Master of Science in Clinical Investigation.