Research fails to show cost-saving benefits of bariatric surgery in obese adults with diabetes

Adults with diabetes who undergo bariatric surgery do not seem to have lower health care costs after surgery, according to data from a recent analysis. The study researchers noted that bariatric surgery has been linked with improvement in many obesity-related conditions, including diabetes, and that one third of all patients who undergo bariatric surgery have type 2 diabetes. In this study, they examined the potential economic benefits associated with the procedure in this patient...

Adults with diabetes who undergo bariatric surgery do not seem to have lower health care costs after surgery, according to data from a recent analysis.

The study researchers noted that bariatric surgery has been linked with improvement in many obesity-related conditions, including diabetes, and that one third of all patients who undergo bariatric surgery have type 2 diabetes. In this study, they examined the potential economic benefits associated with the procedure in this patient population.

The investigators reviewed 2002-08 data from seven BlueCross BlueShield plans for 7,806 individuals with type 2 diabetes who underwent bariatric surgery. Study outcomes included assessments of cost and health care utilization. For each outcome measure, the authors evaluated whether the probability of having any cost/utilization increased or decreased after surgery, assessing a six-year postsurgery period in six separate one-year intervals. In addition, among individuals with any cost/utilization, they assessed the differences in costs/utilization between the presurgery and postsurgery periods.

For total health care costs, the odds of having any costs were lower in the postsurgery period relative to the presurgery period and remained flat with time. However, the authors noted, most beneficiaries had some health care costs after surgery and, among those who did, expenditures were higher after surgery than before. Total mean health care costs were $9,326 before surgery, $13,400 in the first year after surgery and $13,664 in the sixth postsurgical year.

The odds of incurring any inpatient costs were significantly higher after surgery relative to the presurgery period, but only during the first three years. Among the patients with any inpatient costs, postsurgery costs were lower than presurgery costs in year one, but higher in years two through six and generally seemed to increase with time. Cost ratios, which were used to express the difference in cost between the postsurgery and presurgery periods, ranged from 0.58 in the first year after surgery to 3.43 in the sixth year.

In the analyses of outpatient costs, pharmacy costs and "other" costs (e.g., laboratory and diagnostic imaging costs), the odds of incurring any of these costs declined after surgery. However, among those who incurred any of these costs, costs were higher during all six years of the postsurgery period as compared with the presurgery period.

Patients were generally more likely to have hospitalizations after surgery, particularly during the first three years, but they were less likely to have specialist and primary care visits.

The authors of the study noted that the current research contradicts previous findings that showed a cost savings after bariatric surgery, both in a general population and in patients with type 2 diabetes. They suggested that the differences between this and previous research might be explained by differences in the study sample, the larger sample size in this study or the longer length of follow-up.

They also cautioned that, although the current study did not show a cost savings, recent research suggests bariatric surgery is safe in obese patients with diabetes and has clinical benefits, including a reduction in weight-related comorbidities, improved quality of life and improved mobility, which might make the procedure valuable. In addition, the researchers noted, the current study did not consider costs associated with other factors, such as lost productivity.

The investigators called for more long-term research to evaluate whether the higher costs and utilization observed after surgery in this study persist with time or ultimately reverse; to assess drivers of higher utilization; to determine whether increased costs might partially be explained by an increase in elective procedures, such as knee replacement and plastic surgery, that were not available to patients before bariatric surgery; and to better understand clinical determinants of postoperative costs in these patients.

This research was published in the January issue of the journal Medical Care.