Does body mass index influence the decline of glomerular filtration rate in diabetic type 2 patients with diabetic nephropathy in a developing country?

BACKGROUND: Diabetic nephropathy (DN) is associated with a high risk of progression to End Stage Renal Disease (ESRD). While obesity has been identified as a factor in the decline of the glomerular filtration rate (GFR) in chronic kidney disease, its role in the progression of DN remains controversial. The objective of this work is to determine GFR decline in relation to BMI in type 2 diabetic (T2D) patients presenting a DN.
METHODS: A prospective 5-year study conducted in the Eastern region of Morocco. Three BMI groups were distinguished: normal weight, overweight and obese and within each group progressors (eGFR > 5 ml/min/1.73 m(2)/year) and non progressors (eGFR > 5 ml/min/1.73 m(2)/year).
RESULTS: Data on 292 patients were compiled. The progressors represented 25.8%, 23.1% and 32.3% of the normal weight, overweight and obese patient groups respectively (p = 0.29). ESRD was observed in 9.1%, 6.9% and 8.3% (p = 0.21) in normal weight, overweight and obese patients respectively. In multivariate analysis, low-baseline eGFR was identified as important predictor of progression of DN in each BMI group and in the entire cohort independently of BMI. Vascular co-morbidity events occurred in 9.1%, 16.9% and 19.8% (p = 0.04) in normal weight, overweight and obese patients respectively.
CONCLUSION: Our results show that the decline of eGFR in the DN of T2D is not directly influenced by BMI and that the major risk factors contributing to this decline remain low-baseline eGFR and increased baseline albuminuria.