title: Long-term incidence of symptomatic urolithiasis post-bariatric surgery.
abstract: BACKGROUND
  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.
authors.affiliation: Division of Urology, Department of Surgery, McGill University, Montreal, QC;
authors.forename: Nicholas
authors.initials: N
authors.lastname: Haddad
authors.affiliation: Division of Urology, Department of Surgery, McGill University, Montreal, QC;
authors.forename: Patrick
authors.initials: P
authors.lastname: Scheffler
authors.affiliation: Division of Urology, Department of Surgery, McGill University, Montreal, QC;
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Elkoushy
authors.affiliation: Division of Bariatric Surgery, Department of Surgery, McGill University, Montreal, QC;
authors.forename: Olivier
authors.initials: O
authors.lastname: Court
authors.affiliation: Division of Bariatric Surgery, Department of Surgery, McGill University, Montreal, QC;
authors.forename: Nicolas V
authors.initials: NV
authors.lastname: Christou
authors.affiliation: Department of Kinesiology and Physical Education, McGill University, Montreal, QC.
authors.forename: Ross E
authors.initials: RE
authors.lastname: Andersen
authors.affiliation: Division of Urology, Department of Surgery, McGill University, Montreal, QC;
authors.forename: Sero
authors.initials: S
authors.lastname: Andonian