Abstract
Methods: :
97 diabetic patients had baseline evaluations that included the Hospital Depression and Anxiety Scale(HDAS), a detailed ophthalmologic examination, retinal photograph, and measurement of hemoglobin A1C (HbA1c). Diabetic retinopathy(DR) was graded with the International Clinical Classification for DR. Depression and anxiety were measured with the 14-item HDAS for fit to the Rasch model that constructed a hierarchy of the patients, ordered in a linear scale. Differential item functioning (DIF) was performed to examine the confounding effects of demographic variables, severity of retinal vascular changes , and HbA1c level on measurement of depression and anxiety. Regression analysis was performed to determine: 1) correlation between depression or anxiety levels and the presence and severity of retinopathy, 2) whether HbA1C level differed between groups with varying severity of DR.
Results: :
The study included 97 diabetics(mean age of 61, SD 1.1)of whom 50 (52%) were women. The mean depression and anxiety raw scores were 7.2(SD .4) and 8.1(SD .4) respectively. Twenty six (27%) patients classified as no-retinopathy and 31(32%) as non-proliferative (NPDR) and 40(41%) with proliferative (PDR) retinopathy. The average HgbA1C level was 8.1. Regression analysis revealed a small correlation between HbA1C level and varying severity of retinopathy (P=.03); the multiple R value was .06. Analysis of variance did not reveal a statistically significant difference in mean HbA1C when comparing diabetic groups (P=.11).The t-test revealed a statistical difference in mean HbA1C between groups with and without DR (P=.03).Rasch analysis showed a better person separation for depression(.85)than anxiety (0.80) with the mean depression and anxiety measures of -.63(logit) and -.66(logit),respectively. After Banforeni adjustment, no item had a significant DIF for gender, education, ethnicity, and DR stage or macular edema. Regression analysis did not show a significant correlation between the depression or anxiety measures and severity of retinopathy (P>.5) or HbA1c level (P=.9).
Keywords: diabetic retinopathy • diabetes • proliferation