Incidence and progression of diabetic retinopathy in Hispanics and non-Hispanic whites with type 2 diabetes. San Luis Valley Diabetes Study, Colorado.

OBJECTIVE

To learn if Hispanic people with type 2 diabetes have excess incidence and/or progression of diabetic retinopathy and to explore the association of risk factors with diabetic retinopathy.

RESEARCH DESIGN AND METHODS

There were 244 subjects with type 2 diabetes (65.3% Hispanic) with at least one follow-up visit between 1984 and 1992 examined for the development of retinopathy over a median of 4.8 years (range 2.0-6.6 years). Stereo fundus photos were graded by the University of Wisconsin Reading Center.

RESULTS

Of the 169 subjects without retinopathy at baseline, 47 developed some retinopathy, an incidence rate of 63.7 per 1,000 person-years (PY), or a 4-year cumulative incidence of 22.5%. The Hispanic incidence rate was 58.3/1,000 PY (95% CI: 39.4-83.3), which was lower than among non-Hispanic whites, 76.1/1,000 PY (44.3-121.9). Progression occurred in 24 of the 75 subjects with retinopathy at baseline, a 4-year cumulative rate of 24.1%. Logistic regression showed that insulin treatment was associated with higher risk of any retinopathy (odds ratio [OR] = 8.45, 2.65-26.97), and both systolic blood pressure (odds ratio [OR] = 1.58, 0.99-2.52) and total GHb (OR = 1.46, 0.99-2.17) nearly attained statistical significance. After adjustment for multiple potential risk factors, the Hispanic/non-Hispanic white OR was 0.66 (0.28-1.57).

CONCLUSIONS

No excess risk for incident retinopathy was found among Hispanic compared with non-Hispanic white subjects in this population. These results are consistent with our previously reported prevalence data from the same population but differ from reports of excess prevalence among Texas Hispanics. No other Hispanic incidence data are available to assist in reconciling this difference.