Multimorbidity in type 1 diabetes is common and associated with increased mortality

Background: Multimorbidity in type 1 diabetes has previously not been studied in detail. Therefore, we aimed to assess the prevalence of multimorbidity and its association with mortality in type 1 diabetes. Materials and methods: This observational follow-up study includes 4,069 individuals with type 1 diabetes from the Finnish Diabetic Nephropathy study. The prevalence of multimorbidity (coexistence of two or more chronic conditions) was based on 32 conditions at baseline. Conditions were grouped into three subcategories: vascular comorbidities, autoimmune disorders, and other conditions. Hazard ratios (HR) for all-cause mortality were calculated. Results: The prevalence of multimorbidity was 60.4% and increased with age and especially diabetes duration. Multimorbidity was associated with increased risk of mortality, HR 6.0 (95% CI 4.6-7.8), p<0.001. The HR for mortality increased by each additional condition and was 37.9 (95% CI 25.7-56.0) in those with ≥ eight conditions. Vascular comorbidities and other conditions were associated with increased mortality, HRs 5.9 (4.4-7.9) and 3.8 (2.4-5.9), p<0.001, separately, and in combination, HR 11.2 (8.3-15.2), p<0.001. Autoimmune disorders did not influence mortality. Conclusions: Multimorbidity in type 1 diabetes is common and is associated with increased mortality. Comprehensive evaluation of all additional conditions is needed to tailor treatment individually.