The association of interdialytic weight gain with nutritional parameters and mortality risk in hemodialysis patients.

High interdialytic weight gain (IDWG) is considered as an indicator of noncompliance but could also be interpreted as an index of appetite. This study was designed to investigate the relationship IDWG with malnutrition and mortality risk in hemodialysis (HD) patients through a follow-up of 24 months. We divided HD patients into two groups according to their IDWG as Group I (IDWG < 3% of dry weight/day) (27 patients; age 46.8 +/- 21.1 years; HD duration: 28.3 +/- 39.5 months) and Group II (IDWG > or = 3% of dry weight/day) (41 patients; age 40.9 +/- 11.3 years; HD duration: 54.7 +/- 38.7 months). We investigated malnutrition through biochemical analysis (albumin, prealbumin, total cholesterol, creatinine, predialysis potassium and phosphorus levels), normalized protein catabolic rate (nPCR), anthropometric measurements. On initial assessment, group I had significantly lower predialysis creatinine, prealbumin and potassium levels than Group II (p < 0.0001, p < 0.01 and p < 0.001, respectively). At the 24th month, there were significantly lower creatinine, prealbumin, potassium and phosphorus levels in the low-IDWG group. Group I had significantly lower nPCR, body weight, body mass index and triceps skinfold thickness during the follow-up. Over the 24 months, 13 (48.1%) Group I patients and nine (21.9%) Group II patients exhibited loss of dry weight (p < 0.02). According to the survival curves prognosis was significantly poorer for Group I than Group II (2-year survival 74.0% and 92.6%, p < 0.03). Group I individuals with low albumin levels had the worst survival rate (57.1%). In conclusion there is a strong association of IDWG with nutritional parameters in HD patients. Our study draws attention for a possible risk of developing malnutrition in a HD patient with low IDWG.