PROGRESSION RATE TO END-STAGE RENAL-FAILURE IN NONDIABETIC KIDNEY-DISEASES - A MULTIVARIATE-ANALYSIS OF DETERMINANT FACTORS

Background. The respective contribution of the type of nephropathy, ge nder, and proteinuria, and of the potentially alterable factors blood pressure level and daily protein intake on the rate of progression in non-diabetic renal diseases is debated. Methods. We retrospectively an alysed the influence of primary renal disease, gender, urinary protein excretion, mean arterial pressure (MAP), and dietary protein intake o n the rate of decline in creatinine clearance (Delta Ccr) in 159 adult patients with well-defined nondiabetic kidney diseases. All patients had been followed from a baseline Ccr of 40-50 ml/min/1.73 m(2) until endstage renal disease and need for dialysis. Results. Mean (+/-SD) De lta Ccr (ml/min/1.73 m(2)/year) was 9.9+/-6.5 in 51 patients (45 males ) with chronic glomerulonephritis, 6+/-2.5 in 50 patients (26 males) w ith polycystic kidney disease, 5.5+/-2.4 in 17 patients (16 males) wit h hypertensive angionephrosclerosis, and 3.9+/-2 in 41 patients (21 ma les) with chronic tubulointerstitial nephritis. Delta Ccr was higher i n males than in females (7.5+/-5.2 versus 4.8+/-2.5; P<0.001). Linear regression analysis of the whole population disclosed a strong relatio nship between Delta Ccr and proteinuria (r(2)=0.23; P<0.001), and a we ak relationship between Delta Ccr and protein intake (r(2)=0.03; P=0.0 2), but no relationship between Delta Ccr and MAP (r(2)=0.01; P=0.23). Stepwise multiple regression analysis identified the type of nephropa thy, gender, and proteinuria as independent predictive factors of prog ression; however, these factors together accounted for only 36% of the variation in Delta Ccr, suggesting the contribution of other yet unid entified factors. Conclusions. Primary kidney disease and urinary prot ein excretion (reflecting the severity of renal disease in individual cases) appear as the major determinants of the rate of progression, wi th faster progression in males in all types of nephropathy, whereas po tentially alterable factors such as blood pressure and protein intake had only a modest influence in the range of values observed in our pat ients.