High Body Mass Index Reduces Glomerular Filtration Rate Decline in Type II Diabetes Mellitus Patients With Stage 3 or 4 Chronic Kidney Disease

Whether high body mass index (BMI) has an effect on progressive diabetic nephropathy in type II diabetes mellitus (DM) patients with chronic kidney disease (CKD) stage 3 or 4 remains unclear. This prospective study aimed to investigate the relationship between BMI and progression of renal function deterioration in type II DM patients with CKD stage 3 or 4. A total of 105 type II DM patients with CKD stage 3 or 4 participated in this 24-month prospective observational study. Patients were divided into 3 groups according to BMI as follows: normal group, BMI of 18.5–22.9 kg/m(2); overweight group, BMI of 23–24.9 kg/m(2); and obese group, BMI of ≥25 kg/m(2). The primary end point was a 2-fold elevation in serum creatinine levels (measured twice with a 1-month interval) from baseline values, need for long-term dialysis, or death during the 24-month observation period. In the linear regression analysis with the stepwise method, each 1 kg/m(2) increase in BMI led to an increase of 0.32 mL min(−1) × 1.73 m(−2) in the estimated glomerular filtration rate (95% confidence interval, CI, 0.01–0.62; P = 0.04) during the 24-month study period. Moreover, multivariate Cox regression analysis showed that compared with the obese group, the normal BMI group (hazard ratio = 2.76, 95% CI : 1.27–6; P = 0.01) achieved the primary outcome after adjusting for other factors. In this 24-month prospective observational study, we showed that BMI of ≥25 kg/m(2) was a protective factor for renal function deterioration in type II DM patients with CKD stage 3 or 4.