Four-year incidence of diabetic retinopathy in the Los Angeles Latino Eye Study (LALES): Evaluation of how biologic risk indicators and barriers to treatment contribute to disease development
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Objective: To examine 4-year incidence of diabetic retinopathy (DR) and to assess relationships between both biologic indicators and barriers to care on the development of DR.
Methods: The Los Angeles Latino Eye Study (LALES) is a population-based study of primarily Mexican-Americans. Participants were considered at risk for DR if both diabetes was present and they were free of DR at baseline. Definite diabetes was defined as either having 1) a self-reported history and treatment of diabetes, or 2) levels of hemoglobin A1C (HbA1c), or 3) random blood glucose of at least 7.0% and 200 mg/100 mL. All participants underwent a standardized ophthalmic examination. DR was detected by grading of stereoscopic fundus photographs using the modified Airlie House classification scheme. Biologic risk factors, such as HbA1c, random blood glucose, systolic and diastolic blood pressure, were assessed to determine its relationship with incidence of DR. Measures impacting barriers to health care, such as insurance status, were also evaluated to determine its relationship to development of DR. Trend tests were done to assess differences in incidence when stratifying by age and duration of diabetes (defined at baseline). Risk variables were analyzed using logistic regression.
Results: Of the 893 participants with diabetes who were seen at follow-up, 745 had gradable photographs. Of those, only 412 were free of retinopathy at baseline and were considered to be at-risk for DR at follow-up. The four-year cumulative incidence of DR was 27.9% (115/412). Significant increases in incidence were seen across both increasing age (p=0.04) and increasing duration of diabetes (p<0.001) strata. Biologic risk factors shown to increase risk of DR were smaller waist-hip ratio (OR: 1.4; 95% CI: 0.8, 2.6), longer duration of diabetes (OR: 2.5 to 8.3 for 1-4 years to 15+ years, respectively), higher HbA1c (OR: 1.5; 95% CI: 1.3, 1.7), and an increase in HbA1c level from baseline to follow-up (OR: 2.3; 95% CI: 1.2, 4.3). Being born in the US decreased risk for development of DR (OR: 0.4; 95% CI: 0.2, 0.8). Insulin use (OR: 1.1; 95% CI: 0.5, 2.3) confounded the relationship between waist-hip ratio and development of DR. Significant barriers to care that increased the risk of DR were known history of diabetes (OR: 5.2; 95% CI: 2.2, 11.9), lack of vision insurance (OR: 1.8; 95% CI: 1.0, 3.8), increasing age (OR: 0.96; 95% CI: 0.93, 0.99), and an increase in HbA1c by vision insurance interaction (OR: 1.3; 95% CI: 1.03, 1.5). Primary language spoken (English: OR: 0.9; 95% CI: 0.4, 1.9; Both English and Spanish: OR: 1.3; 95% CI: 0.6, 2.6) was a confounder in the model.
Conclusion: Four-year incidence of DR among Latinos is high. Results indicate that this may be due to a combination of both increasing biologic risks as well as increasing barriers to care. High incidence of DR among Latinos suggests the need for initiating screening programs within Latino communities. Biologic indicators and barriers to care found to be significant in this dissertation could be used to identify Latinos that are highly susceptible to developing DR.
Document number: osu1211549705
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=osu1211549705
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