NUTRITION-RELATED PREDICTORS OF SLEEP DURATION IN HEMODIALYSIS PATIENTS

Abstract

We have previously shown that poorer appetite was a significant predictor of decreased sleep quality (SQ) among maintenance hemodialysis (MHD) patients. There is a gap in the literature when examining sleep duration (SD) in MHD patients and the variables that may predict SD. Using data from the HEMO Study, demographic, case mix, nutrition-related and quality of life (QOL) variables were explored as predictors of SD in 1805 MHD patients. Self-reported SD (in hrs) in the last 24 hrs was assessed annually using questions from the KDQOL instrument. A multinominal logistic regression analysis was conducted to determine whether SD (short 0–6; medium 7–9; or long 10+) was associated with the selected variables and Kt/V and flux randomized assignments in a longitudinal (repeated measures) model. At baseline, mean SD was 7.8±2.4 hrs; 33%, 43% and 24% of subjects were in the short, medium and long sleep groups, respectively. In univariate analysis, dietary protein intake, serum albumin, appetite, and QOL measures (mental component score [MCS] and physical component score [PCS]) were significant predictors of SD. In multivariate analysis, age (P=0.008), race (White vs. Black) (P=0.001), appetite on dialysis days (DD) (P=0.0001), MCS and PCS (P<0.0001, respectively) were also significant predictors of SD. Younger patients and those with good appetite on DD were more likely to sleep less, whereas Blacks and those with higher MCS and PCS were more likely to sleep more. Of the nutrition variables, higher protein intake and better appetite were associated with long vs. short SD in univariate analysis. In multivariate analysis, appetite on DD was the only variable predictive of SD. The odds ratio (95% CI) of having a good appetite for those in the short SD group compared to the medium and long SD groups was 0.81 (0.72, 0.92) and 0.86 (0.78, 0.95), respectively. Further research on SD and appetite and the potential effects of short sleep on inflammation needs to be done in MHD patients.