Abstract 141: Abnormal vibration perception threshold as an indicator of presence of retinopathy in patients with type 2 diabetes : A cross sectional study

Background: Diabetic retinopathy is a microvascular complication that can eventually lead to potential blindness. Timely interventions result in favourable outcomes in preserving eye-sight among patients with diabetic retinopathy, thus improving quality of life. Detectioin of diabetic retinopathy is done by ophthalmologists based on advance symptoms, however, a landmark for early detection has been of variable debate. The aim of the study was to identify the assocation between abnormalvibration perception threshold and presence of retinopathy in patients with type 2 diabetes. Methods: A total of 1662 participants with type 2 diabetes mellitus (595 males, 1067 females) were recruited using a systematic sampling technique, from the endocrinology clinic at the National Hospsital of Sri Lanka. Each participant was assessed for vibration perception threshold using a biothesiometer, and a diabetes retinopathy evaluation was done by a trained medical officer, using retinal photography. A biothesiometer reading of >25 Hz on either leg, was considered as loss of vibration perception. Data were analysed, where associations were assessed using Chi square test at a 5% significance level. Results: The mean (SD) age of the study participants was 58.7 (10.47) years. The sample had a mean (SD) fasting blood sugar level of 156 (66.4) mg/dl and HbA1c value of 8.9% (5.46). 1025 participants had a positive biothesiometer reading, of which, 331 (32.3%) had evidence of diabetic retinopathy. Loss of vibration perception was significantly associated with the presence of diabetic retinopathy (p < 0.05). Subgroup analysis based on sex revealed a significant association between loss of vibration perception among males and females, and the presence of diabetic retinopathy (p < 0.05). Multivariate regression analysis for controlling confounding factors showed a HbA1c >7% (p < 0.05) and a positive vibration perception test (p < d0.05) were significant. Conclusions and recommendations: Vibration perception threshold is an easy assessment that can be carried out in limited resource settings, and can be used as an early sign of referral, to screen for diabetic retinopathy which requires more complex technical expertise. Further evaluation on the association between the two is required to generalize the findings to the local population.