Type 1 diabetes can occur at any age. The majority of literature on type 1 diabetes were reported in children whereas adult-onset type 1 diabetes is less well characterised. This study aims to compare the risk of diabetes-related complications and mortality in Chinese with adult-onset type 1 diabetes versus those with youth-onset type 1 diabetes and adult-onset type 2 diabetes.
Between 2000 and 2018, 2738 people with type 1 and 499,288 with type 2 diabetes underwent metabolic and complication assessment in Hong Kong Hospital Authority. They were followed for incident diabetic ketoacidosis (DKA), severe hypoglycaemia, end-stage kidney disease (ESKD), cardiovascular disease (CVD) and all-cause mortality until 2019.
In multivariable Cox regression adjusted for sex, diabetes duration and calendar year, people with type 1 diabetes diagnosed aged ≥40 years had a lower hazard of DKA (hazard ratio HR [95% CI] 0.47 [0.32–0.70]) but higher hazards of severe hypoglycaemia (HR 1.37 [1.13–1.67]), ESKD (HR 4.62 [2.90–7.37]), CVD (HR 11.44 [6.92–18.91]) and mortality (HR 16.22 [11.43–23.02]) versus those diagnosed aged <20 years. Compared with peers with type 2 diabetes presenting at comparable age, people with type 1 diabetes diagnosed aged ≥40 years had higher age-, sex- and diabetes duration-adjusted hazards of DKA (HR 19.87 [13.95–28.31]), severe hypoglycaemia (HR 3.26 [2.81–3.80]), ESKD (HR 1.58 [1.20–2.09]) and mortality (HR 2.26 [1.96–2.60]), and a similar hazard of CVD (HR 1.11 [0.87–1.43]). These associations remained constant after adjustment for metabolic indices.