Demographic Change in Prevalent Type 1 Diabetes Adult Population, and Association of Risk Factors With Comorbidities and Mortality-Results From the Finnish Diabetes Control Study FinDiCon.

aimsThe objective was to characterise Finnish adults with type 1 diabetes (T1D) and to explore associations between known risk factors, comorbidities and mortality. MATERIALS AND

methodsIndividuals with T1D in 2014-2021 were identified from national health care registers, and data on medication and comorbidities were combined with laboratory measurements from hospital data lakes. Comorbidity and risk-factor associations were examined using Cox regression.

resultsWe identified 35 574 adults with T1D. The proportion of individuals aged over 70 years increased during the study period from 7.1% to 12.4% and the proportion of insulin pump users from 10% to 17%. Mean haemoglobin A1c (HbA1c) decreased by 1.7 mmol/mol (0.2%) and mean low-density lipoprotein cholesterol (LDL-c) by 0.2 mmol/L (7.7 mg/dL) from 2014 to 2021. The proportion of individuals with HbA1c > 75 mmol/mol (> 9.0%) reduced slightly (4%-points); this improvement was more prominent in insulin pump users (9%-points). Ketoacidosis was most common in young adults. Prevalence of chronic kidney disease (CKD) increased from 140 (95% CI 136-145) to 168 (95% CI 163-172) per 1000 persons during the study period (p-trend < 0.001). CKD and vascular disease resulted in a multifold increase in the mortality risk, whereas lipid-lowering and antihypertensive medications reduced this risk (p < 0.001 for all).

conclusionsThe proportion of elderly with T1D is increasing, with no concomitant increase in vascular events. Insulin pump therapy has become more common without a concomitant increase in ketoacidosis incidence. HbA1c and LDL-c levels improved during the study. Finnish data indicate a shift in T1D demographics, characterised by improved survival, while rates of diabetes-specific comorbidities remain stable.