Ten-Year Cumulative Incidence of Diabetic Retinopathy. The Beijing Eye Study 2001/2011

OBJECTIVE: To assess the cumulative 10-year incidence of diabetic retinopathy (DR) and its associated factors in a population living in Greater Beijing. METHODS: The population-based longitudinal Beijing Eye Study, which included 4439 subjects (age in 2001: 40+years) in 2001, was repeated in 2011 with 2695 subjects participating (66.4% of the survivors). The study participants underwent a detailed ophthalmic examination. Fundus photographs were examined for the new development of DR. RESULTS: After excluding individuals with DR at baseline (n = 87) or no sufficient fundus photographs in 2011 (n = 6), the study included 2602 subjects with a mean age of 64.6±9.7 years (median: 64.0 years; range: 50 to 93 years). In the 10-year period, 109 subjects (39 men) developed new DR with an incidence of 4.2% (95% confidence interval (CI): 3.45,5.03). In multiple logistic regression analysis, incident DR was significantly associated with higher HbA1c value (P<0.001; Odds Ratio (OR): 1.73; 95% Confidence Interval (CI): 1.35,2.21), longer duration of diabetes mellitus (P<0.001; OR: 1.16; 95% CI: 1.10,1.22), higher serum concentration of creatinine (P = 0.02; OR: 1.01; 95% CI: 1.002,1.022), lower educational level (P = 0.049; OR: 0.74; 95% CI: 0.55,0.99), higher estimated cerebrospinal fluid pressure (P = 0.038; OR: 1.10; 95% CI: 1.01,1.22), and shorter axial length (P<0.001; OR: 0.48; 95% CI: 0.33,0.71). CONCLUSIONS: The cumulative 10-year incidence (mean: 4.2%) of DR in a North Chinese population was significantly associated with a higher HbA1c value, longer known duration of diabetes mellitus, higher estimated CSFP and shorter axial length (P<0.001). Shorter axial length (or hyperopia) and, potentially, higher CSFP may be additional risk factors to be taken into account when counseling and treating patients with diabetes mellitus.