Investigators, however, found no significant correlation between fatigue and objective sleep measures. “This may suggest that sleep disorders and fatigue are different issues in this population,” said lead investigator Manisha Jhamb, MD, MPH, Associate Professor of Medicine at the University of Pittsburgh School of Medicine.
Dr. Jhamb conducted the study because “I feel very strongly about the quality of life issues in this chronically ill population,” she told Renal & Urology News.
Dr. Jhamb and colleagues first measured the Functional Assessment of Chronic Illness Therapy—Fatigue (FACIT-F) scores of 87 stages 4-5 CKD and 86 ESRD patients. FACIT-F is a 13-item scale used primarily in research on cancer patients, and lower scores indicate more fatigue. The mean FACIT-F score in anemic cancer patients is 24, and so the team used this as a dividing line between patients with differing degrees of fatigue.
The subjects’ average FACIT-F score was 34.5, and the CKD and ESRD patients had very similar mean scores, at 34.25 and 34.73, respectively.
The 34 patients (19.6%) with FACIT-F scores of 24 or less—that is, those who were more fatigued— had an average age (around 50 years), proportion of males (about two-thirds), and proportion of African Americans (between 21% and 31%), characteristics similar those of the 139 patients with FACIT-F scores of above 24. Patient with lower FACIT-F scores, however, were more likely to have cardiovascular disease (CVD), use benzodiazepines. and have lower serum albumin and hemoglobin levels.
Among a panel of health-assessment screening tools Dr. Jhamb’s team administered to the patients, FACIT-F score was highly correlated with scores on the Short Form-36 Vitality subscale.
Additionally, the researchers found a significant association between increased fatigue and a reduced percentage of stage 2 sleepand increased patient reported poor sleep quality and daytime sleepiness. The study revealed no correlation between fatigue and other parameters of sleep such as a lower percentage of time spent in stage 3 or rapid eye movement sleep, and increased sleep apnea (as measured by the Apnea-Hypoapnea Index and the Hypoxemic Index).
After adjusting for age, gender, race, and other potential confounders, the investigators found that reduced serum albumin levels, CVD, depression, worse sleep quality, and daytime sleepiness predicted increased fatigue.