In severely obese adults with type 2 diabetes, bariatric surgery reduces the incidence of microvascular complications, including nephropathy, reports a study in Annals of Internal Medicine.
The retrospective study included 4024 patients who underwent bariatric surgery at four US health systems from 2005 to 2011. The patients, aged 19 to 79, were followed up to 2015. About three-fourths of patients were women; the same percentage had a body mass index of 40 kg/m2 or higher.
Bariatric surgery patients were matched for age, sex, body mass index, hemoglobin A1c, insulin use, duration of diabetes, and intensity of healthcare use to 11,059 patients who received usual care. A composite of the first incident retinopathy, neuropathy, or nephropathy was compared between groups.
Five-year risk of incident microvascular disease was 16.9% after bariatric surgery versus 34.7% with usual care: adjusted hazard ratio 0.41. The incidence of all three complications was lower in the bariatric surgery group: 4.9% versus 10.0% for nephropathy, 7.2% versus 21.4% for neuropathy, and 7.2% versus 11.2% for retinopathy. Hazard ratios were 0.41, 0.37, and 0.55, respectively. Nephropathy risk was initially higher in the bariatric surgery group, but declined rapidly and remained lower in years 1 through 7.
Previous studies have shown that bariatric surgery can induce remission of type 2 diabetes. The new study is one of the first to look at how surgical treatment for obesity affects the risk of diabetes-related microvascular complications.
The matched cohort study finds about a one-half reduction in the incidence of microvascular complications in the 5 years after bariatric surgery. Although this trend is driven mainly by a reduction in neuropathy, significant reductions in nephropathy and retinopathy are observed as well. The findings “should help patients and providers to better understand the potential tradeoffs of bariatric surgery as treatment of T2DM and help them to make more informed decisions about care,” the investigators conclude [O’Brien R, et al. Microvascular outcomes in patients with diabetes after bariatric surgery versus usual care: A matched cohort study. Ann Intern Med 2018; DOI:10.7326/M17-2383].