Long-term incidence of urolithiasis post-bariatric surgery

Abstract

Introduction: The risk of urolithiasis post-Roux-en-Y gastric bypass (RYGB) surgery is higher when compared to the general population. Calcium and vitamin D supplementation is routinely prescribed to these patients, yet compliance with these supplements is unknown. The aim of this study was to assess the incidence of symptomatic de novo urolithiasis post-RYGB and compliance with calcium and vitamin D supplementation.Methods: A standardized telephone questionnaire was administered to patients who underwent RYGB between 1996 and 2011. Personal and medical histories were obtained with emphasis on episodes of symptomatic urolithiasis and calcium and vitamin D supplementation.Results: The response rate was 48% with 478 patients completing the telephone questionnaire. After a mean follow-up of 7.0 years (range: 1-15), the incidence of post-RYGB symptomatic urolithiasis was 7.3%, while the rate of de novo symptomatic urolithiasis was 5%. The overall median time to present with symptomatic urolithiasis was 3.1 years, with 3.3 years for de novo stone-formers, and 2.0 years for recurrent stone-formers (p = 0.38). In de novo stone-formers, 33% presented with symptomatic urolithiasis 4 to 14 years postoperatively. Compliance with calcium and vitamin D supplementation was 56% and 51%, respectively.Conclusions: Despite recall bias and lack of confirmatory imaging studies, a high postoperative incidence of symptomatic urolithiasis was found in a large sample of post-RYGB patients. A third of patients with de novo stones, presented with symptomatic urolithiasis 4 to 14 years postoperatively. Compliance with postoperative calcium and vitamin D supplementation was poor and needs improvement.