If you feel fatigued and have rheumatoid arthritis, a number of other factors may also be contributing to your constant feeling of tiredness. A cross-sectional study conducted by the research group of Patricia Katz, PhD, and Edward Yelin, PhD, at the University of California San Francisco identified that poor sleep quality, depression, obesity, and lack of physical activity are also associated with fatigue in rheumatoid arthritis patients.
“Fatigue is a major concern for individuals with rheumatoid arthritis,” wrote Dr. Katz in the article “Sleep Disturbance, Depression, Obesity, and Physical Inactivity Explain a Significant Portion of Fatigue in Rheumatoid Arthritis,” published in the journal Arthritis Care & Research. “However, in order to treat fatigue adequately, its sources need to be identified.”
To begin understanding what causes fatigue in rheumatoid arthritis patients, the team collected data from 158 patients during a single home visit. During the home visits, researchers gathered information regarding sleep quality, depression, physical activity, muscle strength, functional limitations, and body composition, in addition to rheumatoid arthritis disease severity. These different risk factors were selected based on literature and the theoretical mismatch between disability and an individual’s capacity to perform activities.
The majority (85%) of patients evaluated in these exams were female, and the mean age was 59 years old. For these patients, the research team was primarily interested in the Fatigue Severity Index averaged over the past seven days. This score has been validated in a variety of studies and is a reliable indication of fatigue. After collecting data, the team conducted statistical analysis to determine if any of the measured risk factors correlated to Fatigue Severity Index.
While demographic characteristics did not correlate to fatigue, all non-rheumatoid arthritis specific risk factors correlated to fatigue. These included higher resting heart rate, poor sleep quality, depression, physical inactivity, obesity, muscle weakness in the hip, low lean-to-fat mass ratio, and smoking. Of the rheumatoid arthritis specific risk factors, greater disease activity (measured using Rheumatoid Arthritis Disease Activity Index scores), higher dosages of oral prednisone treatment, greater systemic inflammation (indicated by serum C-reactive protein levels), and functional limitations (measured using the Health Assessment Questionnaire) were correlated to fatigue.
“This study presents novel additions to the study of factors potentially affecting fatigue in rheumatoid arthritis,” commented Dr. Katz. She noted that the study is “the most comprehensive range of fatigue predictors to date.”
Although patients with rheumatoid arthritis are significantly more affected by fatigue than some other individuals, the authors identified that fatigue is more a result of a constellation of risk factors, not only those related to rheumatoid arthritis disease severity.
