Consequences of Interdialytic Weight Gain Among Hemodialysis Patients

Background Interdialytic weight gain (IDWG) is a marker of higher pre-dialysis blood pressure, nutrition, and survival in hemodialysis (HD) patients. However, this relationship is incompletely characterized. In this study, we seek to define the association of IDWG/dry weight x100 (IDWG%) on blood pressure (BP), and the nutritional status of an HD population. Material and Methods This study was performed on 300 HD patients. The data was collected over four weeks, including total IDWG, IDWG%, and blood pressure. Normalized protein nitrogen appearance (nPNA), and serum albumin were used as markers of nutritional status. Participants were divided into three groups according to the mean of the IDWG% between two sessions of HD (group A < 3%, group B = 3% - 3.9%, and group C ≥ 4%); they were then compared on various aspects. Student t-test, analysis of variance (ANOVA), and linear regression analysis were used as statistical tools. Results The mean (± standard deviation (SD)) age was 61.7 ± 14.2 years with 57.7% of the patients being male and 42.3% being female. The mean IDWG% for the whole studied population was 3.72% ± 1.73%. Between these three groups, a higher IDWG% was associated with younger males (p = 0.032), lower dry weight (p = 0.009), and longer duration on HD therapy (p = 0.009). IDWG% was directly associated with lower pre-dialysis serum sodium (p = 0.04), higher pre-dialysis serum creatinine (P = 0.002), and lower body mass index (BMI) (p= 0.003). Between these three groups, interdialytic variations in weight gain were not associated with increased BP. There was no significant difference between the three groups in terms of nPNA and serum albumin.  Conclusions The most important associations of IDWG% are age, weight, pre-dialysis sodium, serum creatinine, and duration of dialysis (months). There was no association between IDWG% and increased systolic BP. IDWG% had no association with nutritional status.