Contribution of comorbid conditions to the association between diabetes and disability pensions: a population-based nationwide cohort study

Objectives Using Swedish population-based register data, we examined the extent to which comorbid conditions contribute to the risk of disability pension among people with diabetes. Methods We carried out Cox proportional hazard analyses with comorbid conditions as time-dependent covariates among 14 198 people with newly diagnosed diabetes in 2006, and 39 204 people free from diabetes during the follow-up from 2007-2010. The average follow-up times were 46 and 48 months for those with and without diabetes, respectively. Results For those with diabetes only, the incidence of all-cause disability pension was 9.5 per 1000 person years. The highest incidence of disability pension were for those with: diabetes and depression (23.6); diabetes and musculoskeletal disorder (30.6), and those with diabetes and more than one comorbid condition (36.5). The incidence rate was 5.8 for those without diabetes. Diabetes was associated with a 2.30 times [95% confidence interval (95% CI) 2.09-2.54] higher risk of disability pension (adjusted for sociodemographic factors). This association attenuated by 41% after further adjustment for comorbid chronic conditions. While diabetes was a risk factor for disability pension due to musculoskeletal disorders and diseases of the circulatory system, even after accounting for the above-mentioned conditions, the association between disability pension due to mental disorders and diabetes was diluted after adjustment for mental disorders. Conclusions Although diabetes is an independent risk factor for disability pension, comorbid conditions contribute to this risk to a large degree.