ROLE OF AN IMPROVEMENT IN ACID-BASE STATUS AND NUTRITION IN CAPD PATIENTS

Short-term correction of metabolic acidosis in normal and uremic subje cts has been shown to decrease protein degradation, but the lone-term effects of better correction of acidosis on nutrition in ESRF are unkn own. The aim of this study was to assess the possible benefits, in the nutritional state and morbidity, of improved correction of acidosis i n the first year of treatment with continuous ambulatory peritoneal di alysis (CAPD). Two hundred consecutive new CAPD patients were randomiz ed, in a single-blind fashion, to receive a high (HA; lactate 40 mmol/ liter) or low (LA; lactate 35 mmol/liter) alkali dialysate for one yea r. Calcium carbonate and sodium bicarbonate were also used to correct acidosis in the HA group. Ar one year, the venous serum bicarbonate an d arterial pH were 7.44 +/- 0.004 and 27.2 +/- 0.3 mmol/liter in the H A group, and 23.0 +/- 0.3 mmol/liter and 7.4 +/- 0.004 in the LA group (P < 0.001). Dialysis dose, at one year or at the point of leaving th e study (HA 8.0 +/- 0.1 liters/day vs. LA 8.5 +/- 0.3 liters/day) was not significantly different (P = 0.18). At one year, the increase in b ody weight in the HA group (6.1 +/- 0.66 kg) was higher than in the LA group (3.71 +/- 0.56 kg, P < 0.05). The increase in midarm circumfere nce in the HA patients (1.26 +/- 0.16 cm) was significantly higher tha n the increase in the LA patients (0.61 +/- 0.16 cm, P < 0.05). The in crease in triceps skinfold thickness were not significantly different (HA 2.5 +/- 0.41 mm vs. LA 1.24 +/- 0.38 mm, P = 0.1). Serum albumin w as 37.8 +/- 0.4 g/dl at one year in the HA group, and 38.2 +/- 0.5 g/d l in the LA group (NS). Dietary protein intake at one year (HA 0.9 +/- 0.2 g/kg/day vs. LA 1.0 +/- 0.1 g/kg/day) was not significantly diffe rent. There were fewer hospital admissions in the HA group (1.13 +/- 0 .16 per patient per year) compared to the LA group (1.71 +/- 0.22 per patient per year, P < 0.05). The HA patients spent less days in hospit al per year than the LA patients (16.4 +/- 1.4 days/year vs. 21.2 +/- 1.9 days/year; P < 0.05). It is concluded that better correction of me tabolic acidosis leads to greater increases in body weight and midarm circumference, but not triceps skinfold thickness, in the first year o f CAPD. The improvement in morbidity, in terms of number of admissions and days in hospital per year, may be associated with the improvement in nutritional state.