Diabetic retinopathy as an independent marker of cardiovascular disease in type 1 diabetes: Results from a nationwide longitudinal matched case–cohort study

Abstract

AbstractPurposeTo investigate diabetic retinopathy (DR) as a potential marker of cardiovascular disease (CVD) in adults with type 1 diabetes attending the Danish DR‐screening programme and non‐diabetes adults.MethodsIn this registry‐based matched case–cohort study, we identified 16 547 adults with type 1 diabetes, who were registered in the Danish Registry of Diabetic Retinopathy (DiaBase). Each case was age‐ and sex‐matched by five non‐diabetes individuals (n = 82 399), and odds ratios (ORs) and hazard ratios (HRs) were estimated for incident and upcoming CVD in multivariable models.ResultsAdults with type 1 diabetes (median age 44.5 years, 57.6% male) were more likely to have prevalent CVD (OR 1.29; 95% CI, 1.20–1.38) and to develop CVD within 5 years (HR 1.19; 95% CI, 1.08–1.30) as compared to non‐diabetes control. However, adults without DR were less likely to develop CVD (HR 0.84; 95% CI, 0.72–0.97) compared to the reference population. For adults with type 1 diabetes, there was an increasing risk for incident CVD for increasing levels of DR (HR 1.33, 1.95, 1.71 and 2.39 for DR‐levels 1–4, respectively). Patients with CVD at the time of the first screening had a higher risk to develop DR during follow‐up (HR 1.23; 95% CI, 1.02–1.49).ConclusionIn a nationwide matched case–cohort study adjusted for potential confounders, DR was identified as an independent marker of prevalent and incident CVD in type 1 diabetes with increasing risk demonstrated for higher levels of DR. Likewise, CVD also independently predicted the risk of incident DR.