title: Ecological momentary assessment of fatigue, sleepiness, and exhaustion in ESKD.
abstract: BACKGROUND
  Many patients on maintenance dialysis experience significant sleepiness and fatigue. However, the influence of the hemodialysis (HD) day and circadian rhythms on patients' symptoms have not been well characterized. We sought to use ecological momentary assessment to evaluate day-to-day and diurnal variability of fatigue, sleepiness, exhaustion and related symptoms in thrice-weekly maintenance HD patients.
  
  
  METHODS
  Subjects used a modified cellular phone to access an interactive voice response system that administered the Daytime Insomnia Symptom Scale (DISS). The DISS assessed subjective vitality, mood, and alertness through 19 questions using 7- point Likert scales. Subjects completed the DISS 4 times daily for 7 consecutive days. Factor analysis was conducted and a mean composite score of fatigue-sleepiness-exhaustion was created. Linear mixed regression models (LMM) were used to examine the association of time of day, dialysis day and fatigue, sleepiness, and exhaustion composite scores.
  
  
  RESULTS
  The 55 participants completed 1,252 of 1,540 (81%) possible assessments over the 7 day period. Multiple symptoms related to mood (e.g., feeling sad, feeling tense), cognition (e.g., difficulty concentrating), and fatigue (e.g., exhaustion, feeling sleepy) demonstrated significant daily and diurnal variation, with higher overall symptom scores noted on hemodialysis days and later in the day. In factor analysis, 4 factors explained the majority of the observed variance for DISS symptoms. Fatigue, sleepiness, and exhaustion loaded onto the same factor and were highly intercorrelated. In LMM, mean composite fatigue-sleepiness-exhaustion scores were associated with dialysis day (coefficient and 95% confidence interval [CI] 0.21 [0.02 - 0.39]) and time of day (coefficient and 95% CI 0.33 [0.25 - 0.41]. Observed associations were minimally affected by adjustment for demographics and common confounders.
  
  
  CONCLUSIONS
  Maintenance HD patients experience fatigue-sleepiness-exhaustion symptoms that demonstrate significant daily and diurnal variation. The variability in symptoms may contribute to poor symptom awareness by providers and greater misclassification bias of fatigue related symptoms in clinical studies.
authors: Division of Nephrology and Hypertension, Vanderbilt University Medical Center, 1161 21st Avenue South, MCN S-3223, Nashville, TN 37232-2372, USA. khaled.abdel-kader@vanderbilt.edu.
authors: Khaled
authors: K
authors: Abdel-Kader
authors: Manisha
authors: M
authors: Jhamb
authors: Lee Anne
authors: LA
authors: Mandich
authors: Jonathan
authors: J
authors: Yabes
authors: Robert M
authors: RM
authors: Keene
authors: Scott
authors: S
authors: Beach
authors: Daniel J
authors: DJ
authors: Buysse
authors: Mark L
authors: ML
authors: Unruh
mesh_terms: D006970:Disorders of Excessive Somnolence / Q000191:economics* / Q000209:etiology*; D005221:Fatigue / Q000191:economics* / Q000209:etiology*; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data; D006801:Humans; D007676:Kidney Failure, Chronic / Q000191:economics* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects* / Q000191:economics*; D016896:Treatment Outcome; D014481:United States