Research Article

Association of Metformin Treatment with Reduced Severity of Diabetic Retinopathy in Type 2 Diabetic Patients

Figure 2

Odds ratios that indicate the association between the rate of SNPDR/PDR and hypoglycemic therapy in all cases and within each stratum of metformin, sulfonylurea, and insulin users. Metformin- or sulfonylurea-treated patients were significantly less likely to have SNPDR/PDR when all cases were assessed, while insulin users were more likely to have SNPDR/PDR versus those did not use insulin. When stratified for the use of each hypoglycemic agent, metformin showed independent association with lowered frequency of SNPDR/PDR within each stratums of hypoglycemic treatment, with statistical significance in sulfonylurea users, nonsulfonylurea users, and insulin users. However, sulfonylurea-associated significantly lower rate of SNPDR/PDR was only observed in insulin users. Insulin was associated with higher rate of SNPDR/PDR, which persisted in all the four cohorts stratified by metformin or sulfonylurea. Three of the four ORs had borderline values. OR: odds ratio; SNPDR/PDR: severe nonproliferative diabetic retinopathy/proliferative diabetic retinopathy.