Obesity and erectile dysfunction among type 2 diabetes mellitus patients: Applications of binary, ordinal, and polytomous logistic regression models

PURPOSE: The purpose of this article is to provide a synthesized review of the models for analyzing data with ordinal response as the outcome variable and to evaluate their usefulness in examining the association of obesity with erectile dysfunction (ED) among type 2 diabetes mellitus patients. MATERIALS AND METHODS: A total of 204 married men aged 20–60 years with a diagnosis of type 2 diabetes at the outpatient unit of the Department of Endocrinology at PSG Hospitals during May and June 2019 were studied. We examined the association between obesity and ED using binary, ordinal, and polytomous regression models. RESULTS: Logistic regression model revealed that patients with diabetes who are obese, have a higher odds of ED (odds ratio = 2.508) after adjusting the effect of age and physical activity. In proportional odds model, obesity as compared with normal, independently increased the odds of ED (odds ratio = 2.264) across three severity categories. In the polytomous regression model, it was observed that mild ED has an odds ratio of 3.136 with respect to normal erectile function. It was observed that a cutoff value of waist circumference more than 92.71 cm would be suitable for the classification of ED in diabetic patients. CONCLUSION: The study considered the ordinal nature of the outcome variable investigated and supported the association of obesity and ED among type 2 diabetes. In addition, we have also suggested an optimum cutoff value to waist circumference among diabetic patients with high ED.