Cohort study on incidence of new-onset type 2 diabetes in patients after bariatric surgery and matched controls.

ABSTRACT

BACKGROUND: Metabolic bariatric surgery the reduces risk of new-onset type 2 diabetes in individuals with obesity, but it is unclear whether the benefit varies by sex, age, or socioeconomic status. The aim was to assess the risk of new-onset type 2 diabetes after metabolic bariatric surgery in these subgroups. METHODS: The Finnish Public Sector study, a follow-up study with matched controls nested in a large employee cohort, included patients without type 2 diabetes and with a diagnosis of obesity or self-reported BMI of at least 35 kg/m2. For each patient who had laparoscopic metabolic bariatric surgery (2008-2016), two propensity-score matched controls were selected. New-onset type 2 diabetes was ascertained from linked records from national health registries. RESULTS: The study included a total of 917 patients and 1811 matched controls with obesity. New-onset type 2 diabetes was diagnosed in 15 of the patients who had metabolic bariatric surgery (4.1 per 1000 person-years) and 164 controls (20.2 per 1000 person-years). The corresponding rate ratio (RR) was 0.20 (95% c.i. 0.12 to 0.35) and the rate difference (RD) was -16.1 (-19.8 to -12.3) per 1000 person-years. The risk reduction was more marked in individuals of low socioeconomic status (RR 0.10 (0.04 to 0.26) and RD -20.6 (-25.6 to -15.5) per 1000 person-years) than in those with higher socioeconomic status (RR 0.35 (0.18 to 0.66) and RD -11.5 (-16.9 to -6.0) per 1000 person-years) (Pinteraction = 0.017). No differences were observed between sexes or age groups. CONCLUSION: Metabolic bariatric surgery was associated with a reduced risk of new-onset type 2 diabetes in men and women and in all age groups. The greatest benefit was observed in individuals of low socioeconomic status.

Metabolic bariatric surgery reduces the risk of new-onset type 2 diabetes in individuals with obesity or severe obesity. The risk of new-onset type 2 diabetes after metabolic bariatric surgery varies between socioeconomic status subgroups. In this prospective study, new-onset type 2 diabetes occurred in 1.6% of 917 patients who underwent metabolic bariatric surgery and 9.1% of 1811 propensity score-matched controls. Risk reduction was more marked in individuals of low socioeconomic status. There were no differences between sex or age groups. The reduced risk of new-onset type 2 diabetes after metabolic bariatric surgery emphasizes the need to increase access to treatment in patients with severe obesity. As the preventive effect was most pronounced in individuals of low socioeconomic status associated with both greater burden of disease and worse access to healthcare, the findings need to be taken into account in health policies to reduce health inequalities.