Impact of the era of diabetes onset in a national care system on the prevalence of retinopathy and microalbuminuria in people living with type 1 diabetes 15 years post‐diagnosis: A cross‐sectional, real‐world observational study

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.