Prevalence of Diabetic Retinopathy and Associated Mortality Among Diabetic Adults With and Without Chronic Kidney Disease

Abstract

To estimate prevalence and severity of diabetic retinopathy (DR) among U.S. adults with diabetes and with or without chronic kidney disease (CKD), and assess associated risk of mortality. Cross-sectional study with national survey data. The cohort included adults ≥40 years old with diabetes in the National Health and Nutrition Examination Surveys (NHANES) 2005-2008. Vital status was determined through December 31, 2011. We defined diabetes as hemoglobin A1c ≥6.5% or self-report and CKD by urinary albumin/creatinine ≥30mg/g or glomerular filtration rate <60mL/min/1.73 m2. The main outcomes were DR and mortality. Prevalence of DR was 27.8% (95% CI 24.3-31.7), 36.2% (95%CI 30.1-42.7), and 23.4% (95% CI 19.2-28.1), overall, with and without CKD. Prevalence of vision-threatening DR was 4.2% (95% CI 3.2-5.5), 8.2% (95% CI 5.4-12.2), and 2.0% (95% CI 1.2-3.5), respectively. In a multivariable adjusted model, DR was positively but nonsignificantly associated with CKD (OR= 1.1, 95% CI 0.7-1.7), was 40% higher per 1% increase in hemoglobin A1c (OR= 1.4, 95% CI 1.1-1.6), was 30% higher per 5 years additional diabetes duration (OR= 1.3, 95% CI 1.1-1.5), was 30% higher per 10mm Hg increase in systolic blood pressure (OR= 1.3, 95% CI 1.1-1.5), and was 6-fold higher with insulin treatment (OR= 6.2, 95% CI 2.6-14.8). Compared with diabetic participants with neither DR nor CKD, those with DR and CKD had a 3.6-fold (95% CI 1.5-9.1) increased adjusted risk for all-cause mortality. Over one third of persons with diabetes and CKD had DR. The risk of death was higher with than without CKD and DR. Many of the studied risk factors associated with DR are modifiable.