Cardiovascular disease and mortality in patients with type 2
diabetes after bariatric surgery in Sweden: a nationwide,
matched, observational cohort study
Bj.rn Eliasson, Vasileios Liakopoulos, Stefan Franz.n, Ingmar N.slund, Ann-Marie Svensson, Johan Ottosson, Soffi a Gudbj.rnsdottir
Background In patients with diabetes and obesity specifi cally, no studies have examined mortality after bariatric
surgery. We did a nationwide study in Sweden to examine risks of cardiovascular disease and mortality in patients
with obesity and diabetes who had undergone bariatric surgery (Roux-en-Y gastric bypass [RYGB]).
Methods In this nationwide, matched, observational cohort study, we merged data for patients who had undergone
RYGB registered in the Scandinavian Obesity Surgery Registry with other national databases, and identifi ed matched
controls (on the basis of sex, age, BMI, and calendar time [year]) who had not undergone bariatric surgery from the
National Diabetes Registry. We assessed risks of cardiovascular disease and death using a Cox proportional-hazards
regression model and other methods to examine the treatment eff ect while accounting for residual confounding.
Primary outcomes were total mortality, cardiovascular death, and fatal or non-fatal myocardial infarction.
Findings Between Jan 1, 2007, and Dec 31, 2014, we obtained data for 6132 patients who had undergone RYGB and
6132 control patients who had not. Median follow-up was 3.5 years (IQR 2.1–4.7). We noted a 58% relative risk
reduction (hazard ratio [HR] 0.42, 95% CI 0.30–0.57; p<0.0001) in overall mortality in the RYGB group compared
with the controls. The risk of fatal or non-fatal myocardial infarction was 49% lower (HR 0.51, 0.29–0.91; p=0.021)
and that of cardiovascular death was 59% lower (0.41, 0.19–0.90; p=0.026) in the RYGB group than in the control
group. 5 year absolute risks of death were 1.8% (95% CI 1.5–2.2) in the RYGB group and 5.8% (5.0–6.8) in the
Interpretation Our fi ndings provide support for the benefi ts of RYGB surgery for patients with obesity and type 2
diabetes. The causes of these benefi cial eff ects may be the weight reduction per se, changes in physiology and
metabolism, improved care and treatment, improvements in lifestyle and risk factors, or combinations of these
Funding Swedish Association of Local Authorities and Regions and Region V.stra G.taland.
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