Impact of bariatric surgery on health care utilization and costs among patients with diabetes.

Background: The effect of bariatric surgery on health care utilization and costs among individuals with type 2 diabetes remains unclear. Objective: To examine health care utilization and costs in an insured cohort of individuals with type 2 diabetes after bariatric surgery. Research Design: Cohort study derived from administrative data from 2002 to 2008 from 7 Blue Cross Blue Shield Plans. Participants: Seven thousand eight hundred six individuals with type 2 diabetes who had bariatric surgery. Measures: Cost (inpatient, outpatient, pharmacy, and others) and utilization (number of inpatient days, outpatient visits, specialist visits). Results: Compared with presurgical costs, the ratio of hospital costs (excluding the initial surgery), among beneficiaries who had any hospital costs, was higher in years 2 through 6 of the postsurgery period and increased over time [post 1: odds ratio (OR) = 0.58; 95% confidence interval (CI), 0.50-0.67; post 6: OR = 3.43; 95% CI, 2.60-4.53]. In comparison with the presurgical period, the odds of having any health care costs was lower in the postsurgery period and remained relatively flat over time. Among those with hospitalizations, the adjusted ratio of inpatient days was higher after surgery (post 1: OR = 1.05; 95% CI, 0.94-1.16; post 6: OR = 2.77; 95% CI, 1.57-4.90). Among those with primary care visits, the adjusted OR was lower after surgery (post 1: OR = 0.80; 95% CI, 0.78-0.82; post 6: OR = 0.66; 95% CI, 0.57-0.76). Conclusions: In the 6 years after surgery, individuals with type 2 diabetes did not have lower health care costs than before surgery.