Association between delay in diabetes development and mortality in people with obesity: Up to 33 years follow-up of the prospective Swedish Obese Subjects study.

AIMS

Life expectancy is reduced in people with obesity and is further reduced in those with concomitant type 2 diabetes. The aim of the study was to assess whether a 2-year delay in diabetes development influences life expectancy in people with obesity.

MATERIALS AND METHODS

Participants from the Swedish Obese Subjects study without diabetes at baseline and known diabetes status at the 2-year follow-up were included: bariatric surgery (n = 1471) and usual obesity care (n = 1392). Median follow-up was 26.1 years (interquartile range: 22.7-28.7 years). The Swedish Cause of Death Register, case sheets and autopsy reports were assessed to determine the direct cause of death. Analyses were adjusted for preselected risk factors: inclusion year, sex, baseline age, body mass index (BMI) and smoking.

RESULTS

Across both study arms, 146 participants were newly diagnosed with type 2 diabetes at the 2-year examination, whereas 2717 remained diabetes-free. Most participants diagnosed with diabetes (n = 140) were from the usual care control group. During the follow-up, there were 18.3 deaths per 1000 person-years (95% confidence interval [CI]:14.1-23.9) in the group with diagnosed diabetes at the 2-year follow-up and 10.9 deaths per 1000 person-years (95% CI:10.2-11.8) in the group that remained diabetes-free (adjusted hazard ratio [HRadj] 1.60, 95% CI: 1.19-2.15, p = 0.002). The adjusted median life expectancy in the diabetes group was 3.7 years (95% CI: 1.4-6.0, p = 0.002) shorter than in the diabetes-free group. Specifically, cardiovascular mortality was higher in the group with diabetes (adj sub-hazard ratio [sub-HR] 1.74 [95% CI: 1.09-2.77], p = 0.021).

CONCLUSIONS

A 2-year delay in diabetes development may be linked to increased life expectancy, possibly due to a reduction in cardiovascular mortality. Future studies should confirm these findings.