Effect of Roux-en-Y gastric bypass on pharmacologic dependence in obese patients with type 2 diabetes

Background More than half the diabetes-related health care costs in Canada relate to drug costs. We aimed to determine the effect of Roux-en-Y gastric bypass (RYGB) on the use of insulin and orally administered hypoglycemic medications in patients with diabetes. We also looked to determine overall cost savings with the procedure. Methods We reviewed the bariatric clinic records of all patients with a confirmed diagnosis of type 2 diabetes mellitus who underwent RYGB between 2010/11 and 2014/15. Percentage estimated weight loss was recorded at 1 year, along with reductions in glycated hemoglobin (HbA(1c)) level and use of oral hypoglycemic therapy and insulin. We estimated medication costs using Manitoba-specific pricing data. Results Fifty-two patients with at least 12 months of complete follow-up data were identified. The mean percentage estimated weight loss was 50.2%. The mean HbA(1c) level decreased from 7.6% to 6.0%, the mean number of orally administered hypoglycemics declined from 1.6 to 0.2, and the number of patients receiving insulin decreased from 18 (35%) to 3 (6%) (all p < 0.001). The rate of resolution of type 2 diabetes was 71%. Estimated mean annual per-patient medication costs decreased from $508.56 to $79.17 (p < 0.001). Potential overall health care savings could total $3769 per patient in the first year, decreasing to $1734 at 10 years. Conclusion Roux-en-Y gastric bypass resulted in significant improvement in diabetic control, with a reduction in hypoglycemic medication use and associated costs in the early postoperative period. Potentially, large indirect and direct cost savings can be realized in the longer term.