Association of systemic risk factors with the severity of retinal hard exudates in a north Indian population with type 2 diabetes

Abstract

Background: The various risk factors for diabetic retinopathy and its spectrum are still poorly understood in the Indian population.

Aims: To study the association of various systemic risk factors with retinal hard exudates in type 2 diabetic north Indian patients and to measure the incidence of dyslipidemia in them.

Settings and design: A tertiary-hospital-based cross-sectional study.

Materials and methods: An observational case-study which included 180 type 2 diabetic patients (180 eyes) of nonproliferative diabetic retinopathy (NPDR) with clinically significant macular edema (CSME). In these patients the retinal hard exudates were graded on a central 500 fundus picture using modified Airlie House classification and divided into three groups of absent or minimal hard exudates (Group 1), hard exudates present (Group 2) and prominent hard exudates (Group 3). Their association with various risk factors, namely the age of onset of diabetes and its duration, gender, insulin therapy, and various systemic parameters like hypertension, blood hemoglobin, glycosylated hemoglobin, serum (s.) creatinine levels, 24-h proteinuria and complete lipid profile including total s. cholesterol, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), very low-density lipoprotein cholesterol (VLDL) and s. triglyceride (TG) was studied. The incidence of dyslipidemia was also calculated among these groups of patients.

Statistical analysis: ANOVA test, linear regression analysis and Spearman's correlation test.

Results: On univariate analysis, the retinal hard exudates were significantly associated with s. creatinine (P=0.016), systolic blood pressure (P=0.014), s. cholesterol (P < 0.001), s. LDL (P=0.008) and s. TG (P=0.013) levels. While on linear regression analysis, s. cholesterol (P < 0.001) and s. LDL cholesterol (P=0.028) were found to be independent risk factors affecting the density of retinal hard exudates. On Spearman's correlation test, the retinal hard exudates showed a significant positive correlation with systolic blood pressure (P=0.019), s. cholesterol (P < 0.001), LDL (P=0.002) and TG (P=0.014) levels. The incidence of dyslipidemia varied from as high as nearly 70% among patients of Group 3 compared to as low as 18% among Group 1 patients.

Conclusion: Serum cholesterol and LDL are independent risk factors for retinal hard exudates in type 2 diabetic north Indian patients who suffer from a remarkably high incidence of dyslipidemia.