Trends, clinical characteristics, and complications of individuals with type 1 and type 2 diabetes diagnosed below 25 years of age as seen at a tertiary care diabetes centre in India

There has been an increase in the occurrence of Type 1 diabetes and Type 2 diabetes occurring below 25 years of age. In this report, we outline the trends, clinical characteristics, and complications in Type 1 diabetes and Type 2 diabetes diagnosed ≤ 25 years of age, as observed at a tertiary care diabetes centre in India. We conducted a retrospective study involving 10,449 individuals diagnosed with diabetes at age ≤ 25 years who were registered from 2010 to 2023 at a network of diabetes centre in India. Type 1 diabetes was identified by a history of ketoacidosis, low C-peptide levels, and the necessity of insulin from the time of diagnosis. Type 2 diabetes was diagnosed based on the absence of ketosis, preserved C-peptide levels and a response to oral hypoglycemic agents for at least two years. Among 10,449 individuals with diabetes, 45.5% had Type 1 diabetes, 51.6% had Type 2 diabetes, and 2.8% had other types like maturity-onset diabetes of the young (MODY), gestational diabetes mellitus (GDM), or fibrocalculous pancreatic diabetes (FCPD). The average age at diagnosis was higher in Type 2 diabetes (21.1 ± 3.8 years) compared to Type 1 diabetes (13.5 ± 6.4 years). Joinpoint regression analysis revealed a modest but significant increase over time in prevalence of diabetes diagnosed at age 25 or younger [Annual Percent Change (APC): 1.42, 95% CI: 0.12–2.70; p = 0.034], which was more marked in Type 2 diabetes [APC: 2.39, 95% CI: 0.40–4.42; p = 0.021]. Among those with diabetes with a duration of ≥ 15 years, retinopathy was found in 61.0% of Type 1 diabetes and 53.9% of Type 2 diabetes, diabetic kidney disease in 36.1% and 49.1%, and neuropathy in 29.7% and 50.1%, respectively. Logistic regression identified older age at diagnosis, higher BMI, a strong parental history of diabetes, and physical inactivity as key predictors of Type 2 diabetes, when compared to Type 1 diabetes. At this tertiary diabetes centre in South India, Type 2 diabetes is more common than Type 1 diabetes among those with diabetes diagnosed below 25 years of age. The high prevalence of complications points to the need for earlier diagnosis and better glycemic control of both Type 1 diabetes and Type 2 diabetes. Among those with diabetes diagnosed below 25 years of age at a tertiary diabetes centre in South India, Type 2 diabetes is more common than Type 1 diabetes. Complications like retinopathy, diabetic kidney disease, and neuropathy are high, both in Type 1 diabetes and Type 2 diabetes. The high burden of microvascular complications observed in both Type 1 diabetes and Type 2 diabetes suggests suboptimal glycemic control in this youth-onset cohort.