Higher prevalence of complications in young adults diagnosed with type 2 vs. type 1 diabetes

Compared to those with type 1 diabetes, participants with type 2 had a significantly higher age-adjusted prevalence of diabetic kidney disease, retinopathy, peripheral, arterial stiffness, and hypertension by age 21.

Patients with contemporary youth-onset diabetes may be at higher risk for disease-related complications if they have type 2 versus type 1 diabetes, a recent cohort study found.

A population-based registry across five U.S. sites identified 2,018 adolescents and young adults with diabetes who were diagnosed before age 20 (1,746 with type 1 diabetes and a mean age of 17.9 years; 272 with type 2 diabetes and a mean age of 22.1 years). Researchers measured risk factors (e.g., glycemia, obesity, blood pressure levels) at baseline and follow-up at 12, 24, and 60 months before measuring diabetes-related complications and comorbidities (diabetic retinopathy, neuropathy, nephropathy, hypertension, and arterial stiffness) at an outcomes visit.

Results were published online on Feb. 28 by JAMA.

Compared to those with type 1 diabetes, participants with type 2 had a significantly higher age-adjusted prevalence for all outcomes at age 21, with the exception of cardiovascular autonomic neuropathy: diabetic kidney disease (19.9% vs. 5.8%; P<0.001), retinopathy (9.1% vs. 5.6%; P=0.02), peripheral neuropathy (17.7% vs. 8.5%; P<0.001), arterial stiffness (47.4% vs. 11.6%; P<0.001), and hypertension (21.6% vs. 10.1%; P<0.001). Overall, 195 participants with type 2 diabetes (72%) and 562 participants with type 1 diabetes (32%) had evidence of at least one early disease-related complication or comorbidity.

Results were unchanged after adjustment for age, sex, duration of diabetes, and clinical site. The differences in microvascular complications between groups remained significant after adjustment for glycemic control, central obesity, and blood pressure levels over time. Adjustment for race/ethnicity did not attenuate the higher odds of complications among participants with type 2 versus type 1 diabetes for any of the outcomes. For hypertension and arterial stiffness, adjustment for waist-height ratio attenuated the odds ratio to nonsignificance.

Limitations of the study include that only a single measure of each outcome was used (without repeated testing), the relatively small number of participants with some outcomes (especially in subgroup analyses), and the possibility that participants with type 2 diabetes had a longer period of undetected hyperglycemia than those with type 1.

The study authors noted that the prevalence of complications and comorbidities was frequent in both groups and that these rates are likely to increase. “These findings support early monitoring of these patients for development of complications,” they wrote.