Medication utilization and annual health care costs in patients with type 2 diabetes mellitus before and after bariatric surgery.

Objective: To examine the relationship of bariatric surgery with the use of diabetes medications and with total health care costs in patients with type 2 diabetes mellitus.

Design: We studied 2235 adults with type 2 diabetes and commercial health insurance who underwent bariatric surgery in the United States during a 4-year period from January 1, 2002, through December 31, 2005. We used administrative claims data to measure the use of diabetes medications at specified time intervals before and after surgery and total median health care costs per year.

Setting: Seven states in the Blue Cross/Blue Shield Obesity Care Collaborative.

Patients: Two thousand two hundred thirty-five patients with type 2 diabetes mellitus who underwent bariatric surgery.

Results: Surgery was associated with elimination of diabetes medication therapy in 1669 of 2235 patients (74.7%) at 6 months, 1489 of 1847 (80.6%) at 1 year, and 906 of 1072 (84.5%) at 2 years after surgery. Reduction of use was observed in all classes of diabetes medications. The median cost of the surgical procedure and hospitalization was $29,959. In the 3 years following surgery, total annual health care costs per person increased by 9.7% ($616) in year 1 but then decreased by 34.2% ($2179) in year 2 and by 70.5% ($4498) in year 3 compared with a preoperative annual cost of $6376 observed from 1 to 2 years before surgery.

Conclusions: Bariatric surgery is associated with reductions in the use of medication and in overall health care costs in patients with type 2 diabetes. Health insurance should cover bariatric surgery because of its health and cost benefits.