Progression of renal failure in patients with renal disease of diverse etiology on protein-restricted diet.

The rate of progression of early renal failure was evaluated in three groups of adult patients with renal disease of diverse etiology on dietary protein and phosphorus restriction (about 0.6 g/kg of protein, 700 mg of phosphorus) and in a control group of 22 patients with the same renal disease, retrospectively studied, on a free diet. Group 1 had 33 patients with chronic glomerulonephritis (CG), initial serum creatinine (Scr) of 1.4 to 4.3 mg/dl (mean, 2.20), followed for 5 to 94 months (mean, 44). Group 2 had 17 patients with polycystic kidney disease (PKD), Scr 1.3 to 4.7 mg/dl (mean, 2.40), followed for 8 to 81 months (mean, 42). Group 3 had 28 patients with primary chronic pyelonephritis (CP), Scr of 1.5 to 4.5 mg/dl (mean, 2.57), followed for 9 to 92 months (mean, 41). The control group had 22 patients (11 with CG, five with PKD, and six with CP), with Scr 1.7 to 4.1 mg/dl, followed for 6 to 72 months (mean, 24). In the regression analysis between reciprocal creatinine and time, the slopes were -0.0017, -0.0025, and -0.00016 dl/mg/month in the three patient groups on a protein-restricted diet, respectively. The difference between both groups 1 and 2 and group 3 was statistically significant (P less than 0.05). The slopes in patients on a free diet were significantly greater than those found in patients on a protein-restricted diet. The actuarial survival probability at 72 months, assuming as "renal death" a Scr of 10 mg/dl, was 45% in patients with CG, 44% in those with PKD, and 67% in those with CP on a protein-restricted diet.(ABSTRACT TRUNCATED AT 250 WORDS)