AIMS: This study investigates the impact of the era of diabetes onset on the prevalence of diabetic retinopathy and albuminuria 15 years post-diagnosis in people living with type 1 diabetes (T1D) within a national healthcare system offering structured multidisciplinary endocrinology care.

MATERIALS AND METHODS: We analysed data of 2176 individuals diagnosed with T1D before age 30, comparing two cohorts based on diabetes onset period: group A (1985-1998) and group B (1998-2009). The prevalence of diabetic retinopathy and albuminuria was assessed using generalised estimating equations.

RESULTS: Glycaemic control (haemoglobin A1C: 8.3% vs. 8.1%, p < 0.0001) and low density lipoprotein cholesterol (2.6 mmol/L vs. 2.5 mmol/L, p < 0.001) were poorer in group A, whereas obesity prevalence was higher in group B (12.8% vs. 17.4%, p < 0.01). Group A used more antihypertensive therapy (14.9% vs. 11.5%, p < 0.01), while group B used more lipid-lowering therapy (9.2% vs. 15.9%, p < 0.0001). The prevalence of diabetic retinopathy 15 years post-diagnosis significantly declined from 36.3% in 2001 to 21.1% in 2022 (p < 0.0001). This decrease was particularly pronounced in individuals with diabetes onset after 11 years of age. The prevalence of albuminuria, adjusted for age and sex, decreased from 14.9% in 2001 to 7.3% in 2022 (p < 0.05).

CONCLUSIONS: Individuals diagnosed with T1D after 1998 had fewer microvascular complications 15 years post-diagnosis, especially less retinopathy in those with diabetes onset after age 11. This decline highlights the impact of improved care.