THE OTHER SIDE OF THE COIN - INTERDIALYTIC WEIGHT-GAIN AS AN INDEX OFGOOD NUTRITION

Excessive interdialytic weight gain (IDWG) is usually attributed to fl uid and sodium overload. Abnormal thirst regulation, hormonal derangem ents, and social, cultural, and psychological habits may account for l ow compliance with fluid and salt restrictions. However, food intake i s an important determinant of IDWG, and high IDWG may reflect the nutr itional status of hemodialyzed patients, rather than their scanty comp liance. The relationship between IDWG, efficacy of dialysis, and nutri tional status was investigated in 38 patients (28 men and 10 women), i n whom urea kinetics was studied by means of an on-line urea sensor (U M 1000, Baxter Healthcare, McGraw Park, IL), and Kt/V and protein cata bolic rate (PCR) were calculated. Records from 161 dialysis sessions w ere analyzed and grouped according to their IDWG (group A, weight gain > 5% and group B, weight gain < 5% of dry body weight). In group A, K t/V, solute removal index, urea reduction ratio, predialytic blood ure a nitrogen (BUN), urea removed, and PCR were statistically higher than in group B (P < 0.05). Regression analysis showed a significant and p ositive correlation between IDWG and PCR. In 17 of 38 patients with st eadily high IDWG, serum albumin levels, predlalytic BUN, and PCR were significantly higher than in patients with low IDWG (P < 0.05). Sex an d predialytic blood pressure did not correlate with IDWG; in contrast, age negatively affected both IDWG and PCR (age vIDWG and age v PCR, r = 0.22; P < 0.008 and P < 0.006, respectively). These results confirm that high IDWG Is associated with better nutritional status. (C) 1998 by the National Kidney Foundation, Inc.