Mortality patterns in Dutch diabetes outpatients

Aim: Diabetes mellitus is a major cause of death. Outpatients with diabetes have more complications than patients in general practice; mortality patterns have only been studied in the total diabetes population. This study aims to assess mortality, causes, and predictors in outpatients with diabetes. Materials and Methods: A cohort study, included people with diabetes mellitus from the nationwide Dutch Paediatric and Adult Registry of Diabetes (DPARD) visiting diabetes outpatient clinics in 2016-2020. DPARD data were linked to Statistics Netherlands (CBS), comprising data on mortality, ethnicity and education. All-cause and cardiovascular mortality rates were estimated using Cox proportional hazard regression. Results: During a median follow-up of 3.1 years among 12 992 people with diabetes, mortality rates per 10 000 person-years were 67.7 in adult type 1 diabetes and 324.2 in type 2 diabetes. The major cause of non-cardiovascular death was malignancy. During the pandemic years of influenza (2018) and COVID (2020), mortality rates peaked. Age, smoking and an estimated glomerular filtration rate of <60 ml/min were associated with all-cause mortality. In type 2 diabetes, additional factors were male sex, body mass index <20 kg/m², diabetes duration <1 year and hypertension. Conclusions: Mortality among Dutch outpatients with diabetes is high. Smoking and renal failure were associated with mortality in both types. Further focus on early detection and treatment of mortality-associated factors may improve clinical outcomes.