There was no difference in long-term health care cost between conventional treatment and bariatric surgery in patients with diabetes, according to a study published in the Lancet online Sept. 17 .

Elevated body mass index is associated with an increased risk of diabetes. However, devising effective lifestyle interventions to reduce weight in the severely obese remains a challenge. Data from the Swedish Obese Subjects (SOS) study have demonstrated prevention and remission of type 2 diabetes after bariatric surgery.

Catherine Keating, Ph.D., of the Deakin Health Economics and Baker IDI Heart and Diabetes Institute in Melbourne, and her associates sought to quantify the health care costs during a 15-year period for obese patients treated with bariatric surgery versus conventional treatment.

Data on prescription drug costs were obtained by questionnaires from participants in the SOS study and the Swedish Prescribed Drug Register. The Swedish National Patient Register was used to obtain data on the outpatient and inpatient visits. The participants were followed for up to 15 years.

The original SOS study was a prospective study that compared treatment outcomes and costs in two groups of obese adults: those who underwent bariatric surgery versus a control cohort who received conventional obesity management. The participants ranged from 37 to 60 years old with BMIs of greater than 34 kg/m2 in men and greater than 38 in women. Conventional treatment included behavior modification, lifestyle intervention, or no treatment.

The definition of diabetes was based on a self-report of taking diabetes drugs or a fasting glucose measurement.

After exclusions, 4,030 participants were included; of these, 2,836 were euglycemic, 591 had prediabetes, and 603 were diabetic, the investigators reported (Lancet 2015 Sep 16 [doi: 10.1016/


Patients in the bariatric surgery groups were on average 6.2 kg heavier (P less than .0001) and 1.5 years younger (P less than .0001) than were the controls. After the 15-year follow-up, weight loss was 16 kg greater in the diabetes subgroup, 18 kg greater in the prediabetes subgroup, and 20 kg greater in the euglycemia subgroup who had bariatric surgery versus conventional treatment (P less than .0001 for all).

After 15 years, the aggregated drug costs were not different between the conventional treatment group and the bariatric surgery group in patients with euglycemia. However, drug costs were lower in the prediabetic participants who had surgery versus conventional treatment (P = .007). Similarly, patients with diabetes who underwent bariatric surgery incurred lower drug costs after 15 years (P less than .0001).

The inpatient hospital costs after 15 years were greater in the surgery group for all glucose levels versus conventional treatment (mean, $51,225 vs. $25,313; P less than .0001).

There were no differences in outpatient costs demonstrated between the glucose subgroups. However, in the diabetes group, there were wide confidence intervals associated with outpatient costs that were thought to be secondary to end-stage renal disease visits.

Finally, the total cost of health care for the euglycemic group was higher in those who underwent surgery versus conventional treatment (P less than .0001). The prediabetic subgroup also incurred a higher total health care cost for surgery versus conventional treatment (P less than .0001). However, there were no differences in total health care cost for patients with diabetes who had surgery versus conventional treatment ($88,572 vs. $79,967, P less than .090).

The total cost was also higher in patients with diabetes for more than 1 year who had surgical intervention versus those who got conventional treatment (P less than .011). However, patients with diabetes for less than 1 year did not show differences in total cost when treated with surgery versus conventional treatments (P less than .476)

“In this study, we show that for obese patients with type 2 diabetes, the upfront costs of bariatric surgery seem to be largely offset by prevention of future health care and drug use,” the authors wrote. In addition, “long-term health care cost results support prioritization of patients with obesity and type 2 diabetes for bariatric surgery.”

This study was supported by a grant from AFA Forsakring. The authors reported multiple disclosures.


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