Correlations of dietary energy and protein intakes with renal function impairment in chronic kidney disease patients with or without diabetes.

Dietary energy and protein intake can affect progression of chronic kidney disease (CKD). CKD complicated with diabetes is often associated with a decline in renal function. We investigated the relative importance of dietary energy intake (DEI) and dietary protein intake (DPI) to renal function indicators in nondiabetic and diabetic CKD patients. A total of 539 Stage 3-5 CKD patients [estimated glomerular filtration rate (eGFR)<60 mL/min/1.73 m using the Modification of Diet in Renal Disease equation] with or without diabetes were recruited from outpatient clinics of Nephrology and Nutrition in a medical center in Taiwan. Appropriateness of DEI and DPI was used to subcategorize CKD patients into four groups:(1) kidney diet (KD) A (KD-A), the most appropriate diet, was characterized by low DPI and adequate DEI; (2) KD-B, low DPI and inadequate DEI; (3) KD-C, excess DPI and adequate DEI; and (4) KD-D, the least appropriate diet, excess DPI and inadequate DEI. Inadequate DEI was defined as a ratio of actual intake/recommended intake less than 90% and adequate DEI as over 90%. Low DPI was defined as less than 110% of recommended intake and excessive when over 110%. Outcome measured was eGFR. In both groups of CKD patients, DEI was significantly lower (p<0.001) and DPI higher (p=0.002) than recommended levels. However, only in the nondiabetic CKD patients were KD-C and KD-D significantly correlated with reduced eGFR compared with KD-A at increments of -5.63 mL/min/1.73 m (p = 0.029) and -7.72 mL/min/1.73 m (p=0.015). In conclusion, inadequate energy and excessive protein intakes appear to correlate with poorer renal function in nondiabetic CKD patients. Patients with advanced CKD are in need of counseling by dietitians to improve adherence to diets.