Anemia appeared to identify adults with longstanding type 2 diabetes mellitus (T2DM) at particularly high risk for diabetic retinopathy (DR). The findings were reported in a retrospective National Health and Nutrition Examination Survey (NHANES) analysis published in the Journal of Diabetes Research, which showed that sociodemographic and systemic risk factors for DR differed according to diabetes duration.
The retrospective cross-sectional analysis included 2,487 adults with T2DM from NHANES 2005-2020. Participants were stratified according to diabetes duration into Group 1 (≤10 years) and Group 2 (>10 years). Weighted univariate and multivariate logistic regression models adjusted for clinical and demographic covariates were used to evaluate risk factors associated with DR and the combined effect of anemia and diabetes duration on DR occurrence.
Across both diabetes-duration groups, insulin use, diabetic nephropathy (DN), and education level were significantly associated with DR. In participants with diabetes duration ≤10 years, higher glycated hemoglobin (HbA1c), fasting plasma glucose, total cholesterol, and low-density lipoprotein cholesterol were positively associated with DR, whereas earlier age at diabetes diagnosis and higher family income were protective factors.
Among participants with diabetes duration >10 years, anemia and urinary albumin-to-creatinine ratio (UACR) were positively associated with DR, while estimated glomerular filtration rate (eGFR) was negatively associated (all P<.05). After full adjustment, diabetes duration >10 years remained independently associated with DR (OR, 1.53; 95% CI, 1.08-2.16; P=.017).
The combination of anemia and diabetes duration >10 years was associated with more than twofold higher odds of DR after multivariable adjustment (OR, 2.24; 95% CI, 1.30-3.84; P=.004), with a significant synergistic effect observed between prolonged diabetes duration and anemia.
The findings suggest that anemia may help identify patients with longstanding T2DM at elevated risk for DR.
