Survival analysis for diabetic retinopathy in diabetic patients using Extended Cox Model

Abstract

One of the disorders of the eye that may occur to the diabetes patients is diabetic retinopathy. Diabetic retinopathy can cause vision loss and even blindness to the diabetes patients. At first, diabetic retinopathy may not have any symptoms at all. But diabetic retinopathy is the disorder which cause of blindness besides of cataracts, glaucoma and macular degeneration. The objective of this research was to determine the factors that can be used to delay diabetic retinopathy. There are several covariates that used in this research. One of the survival analysis method that can be used is Cox Proportional Hazard model. However, in this research, the result of Cox Proportional Hazard model showed that some covariates are not significant in the Cox Proportional Hazard model and the model did not fulfil the assumption, that is a constant hazard ratio over time. Therefore, an analysis was carried out using the Extended Cox Model. The results of Extended Cox model showed that all variables are concede a significant effect in delaying diabetic retinopathy in the Extended Cox model. Therefore, the Extended Cox model is more appropriate in this research than Cox Proportional Hazard model.