Risk factors for diabetic retinopathy: a case-control study.

BACKGROUND: Diabetic retinopathy (DR) is the major cause of blindness among working age adults. The aim of the study was to investigate risk factors for development of DR.

METHODS: A case-control study was performed based on data from 240 individuals (80 cases and 160 controls) attending the Outpatient Specialty Clinic of the University of South Santa Catarina (UNISUL), between Mar/2010 and May/2014. Data collection occurred through review of medical charts for presence or absence of DR, determined by an ophthalmologist. Study protocol included demographic characteristics, metabolic control, diabetes mellitus (DM) profile and comorbidities. Statistical analysis used Chi square test for qualitative variables and multivariate logistic regression analysis to select independent variables (SPSS(®)18.0 software). Odds ratio (OR) was used as measure of association. The study was approved by research ethics committee of UNISUL.

RESULTS: Mean age of group case was 59.5 years with a slight female predominance. Gender, age, body mass index were not associated with outcome. Individuals with poor glycemic control were more likely to DR (OR 3.83; 95 % CI 1.57-9.37). It was observed a positive relationship between duration of DM and DR, with higher chances in 11-15 years of disease (OR 7.52, 95 % CI 3.03-18.68) and >15 years (OR 9.01, 95 % CI 3.58-22.66). Regarding comorbidities, only diabetic nephropathy showed higher chance for DR (OR 3.32; 95 % CI 1.62-6.79).

CONCLUSIONS: Diabetic patients after 10 years of disease with poor glycemic control and nephropathy have a higher chance of DR.