The relationship between obesity and microvascular complications in type 2 diabetes patients: KNHIS data from 2009-2012

Purpose: To observe if obesity is a representative risk factor for vision-threatening proliferative diabetes retinopathy and end stage renal disease, which are major chronic microvascular complications in Korean Type 2 diabetes patients. Methods: A retrospective data analysis was conducted on 2,524,431 adults over the age of 30 years diagnosed with type 2 diabetes using the Korean National Health Insurance Service-Health Screening database from January 2009 to December 2012. The association of body mass index (BMI) and waist circumference with the occurrence of sight-threatening diabetic retinopathy and end-stage renal disease in type 2 diabetes mellitus patients were analyzed. Results: Multivariable Cox regression analysis was carried out on the potential risk factors related to microvascular complications, including vision-threatening diabetic retinopathy and end-stage renal disease. BMI and microvascular complications showed a reverse linear relationship, but a larger waist circumference was associated with a greater risk of microvascular complications (incidence rate ratio [IRR] = 1.049, 95% confidence interval [CI] = 1.021-1.078; IRR = 1.087, 95% CI = 1.05-1.125, and IRR = 1.234, 95% CI = 1.182-1.289) after adjusting other risk factors. Conclusions: In our study, the results showed that type 2 diabetic patients with a larger waist circumference were at greater risk for microvascular complications. Thus, in addition to the BMI, the waist circumference should be used as the obesity parameter in microvascular complication risk assessment among type 2 diabetic patients.