Effect of low-protein, very-low-phosphorus diet on diabetic renal insufficiency with proteinuria

We describe the clinical outcome of 13 patients with non-insulin-dependent diabetes mellitus (NIDDM), renal insufficiency, and proteinuria, treated for 12.2 +/- 12.9 months (mean +/- SD) with a low-protein, very-low-phosphorus diet (LPVLP) containing 30 g protein and 11.3 mmol (350 mg) phosphorus. After a control period of 18.2 +/- 20.4 months, LPVLP therapy was initiated and serum urea nitrogen, uric acid, and phosphate, as well as urinary excretion of protein, creatinine, urea nitrogen, uric acid, and phosphate, decreased significantly. There was no change in mean blood pressure, hemoglobin, blood pH, and HCO3-, as well as in serum creatinine, protein, albumin, calcium, magnesium, cholesterol, triglyceride, beta-lipoprotein, and high-density lipoprotein (HDL)-cholesterol. Nitrogen balances were measured over 5 weeks in nine patients. Nitrogen balance increased significantly from a negative balance of -0.795 +/- 1.367 g/d in the first week, to almost neutral in the fourth week, and later, was neutral or positive. Neither uremic symptoms nor signs of malnutrition appeared during the LPVLP period. These results suggest that negative nitrogen balance during the initial few weeks does not predict future nutritional status of patients with diabetic renal failure.