Prevalence and risk factors for diabetic retinopathy at diagnosis (DRAD) in patients recently diagnosed with type 2 diabetes (T2D) or latent autoimmune diabetes in the adult (LADA)

Purpose: To study prevalence of diabetic retinopathy (DR) at diagnosis (DRAD) and to estimate contributing risk by sociodemographic, cardiovascular and metabolic characteristics present in patients recently diagnosed with type 2 diabetes (T2D) or latent autoimmune diabetes in the adult (LADA).

Methods: Patients (n=2174) recently diagnosed T2D (93%) or LADA (7%) were included upon arrival for their baseline DR screening. Fundus photographs of 4902 eyes were graded by a senior ophthalmologist according to the International Diabetic Retinopathy Disease Severity Scale. Official registers held by Statistics Sweden provided sociodemographic variables. The National Patient Register and Swedish Prescribed Drug Register were used to assess cardiovascular risk. Beta cell function (HOMA2%b) and insulin sensitivity (HOMA2%s) were estimated from fasting (f) C-Peptide using the homeostasis model assessment (HOMA) 2 calculator. Odds ratios (OR) for DRAD were estimated using generalized estimating equation models.

Results: The prevalence of DRAD was 12% (7% mild and 5% moderate) and of diabetic macular edema it was 11% (all within vascular arch). The prevalence did not significantly differ between T2D and LADA. Due to sample size, the regression analysis of LADA patients did not yield any significant estimates. In T2D low educational level (≤9years) increased risk for DRAD by 44% (OR 1.44; 95% CI 1.07-1.93) and <50% beta-cell function adjusted for HbA1c and insulin sensitivity at diagnosis increased the risk by 77% (OR 1.77; 95% CI 1.28-2.44). For every unit increase in BMI, risk for DRAD decreased by 3% (OR 0.97; 95% CI 0.95-0.99).

Conclusions: DRAD prevalence in patients recently diagnosed with T2D or is 12%. Low educational level and low beta cell function at diagnosis are risk factors for DRAD. Estimation of beta cell function from (f)C-Peptide and (f)P-Glucose may be a valuable tool in identifying patients at risk for DRAD.