Fluctuation of the rate of renal function decline associated with fluctuation of compliance with a low protein diet in patients with diabetic renal failure]

We investigated fluctuation of compliance with a low protein diet and the influence on the rate of decline in renal function. Twenty-seven patients with diabetic renal failure who were prescribed a low protein diet of 0.6 g/kg/day were followed during a period of 12 months. Dietary compliance was evaluated based on a 4-day dietary diary, interview with patients and calculation of the protein catabolic rate from 24-hour urea excretion at every hospital visit. They were judged on a 4-rank system, A(adhered over 75% of the days), B(74-50%), C(49-25%), D(less than 24%). During the twelve months, 55.5% of the patients showed fluctuation of their compliance with the diet. In 17 patients whose compliance fluctuated between rank A and B, their rate of GFR decline(ml/min/month) was significantly faster(-2.40 +/- 2.59 vs 0.99 +/- 1.41, p < 0.01), their rate of serum creatinine elevation(mg/dl/month) was significantly higher(0.90 +/- 0.79 vs -0.42 +/- 0.45, p < 0.01) and their rate of serum urea nitrogen increase(mg/dl/month) was significantly larger(15.3 +/- 12.4 vs -10.0 +/- 12.9, p < 0.01) during the period of rank B than rank A. There were no significant differences in the rates of changes in serum levels of albumin, transffering, HbA1c and body weight between the two periods. In conclusion, fluctuation of compliance with a low protein diet affects the rate of renal function decline synchronizedly in patients with diabetic renal failure.