Background/Purpose: Little is known about the severity and determinants of fatigue in adults with arthritis. We hypothesize that the number of joint sites affected is associated with fatigue through pain severity and sleep problems.
Methods: Data source: a representative sample of people reporting arthritis, the 2009 Survey on Living with Chronic Diseases in Canada – Arthritis Component (age 20+: n=4,565). Variables: frequency and severity of fatigue and of pain, sleep difficulties (a lot, a little, not at all), sites of joint pain (up to 18 joint sites), other chronic conditions, arthritis type (most frequently unknown type or osteoarthritis), and personal characteristics (age, sex, education, income, obesity). The number of joint sites affected were grouped: no pain, single site, 2-3 sites, 4-7 sites, and 8+ sites (widespread). For multivariate analysis, the frequency and severity of fatigue were combined into a continuous score (0 = no fatigue to 100 = always and as bad as it could be). A similar score was calculated for pain. Sequential multivariate linear regression models, controlling for personal and health characteristics were fitted to investigate the relationship of joint site groups, pain severity, and sleep problems with fatigue.
Results: 91.7% reported fatigue with a mean score of 50.4. The average joint site count was 5.1 (95% CI: 4.9-5.3). Over 80% reported multisite joint pain (24.3% 2-3 sites, 25.2% 4-7 sites, 30.4% 8+ sites). There was a significant gradient of higher pain severity and more sleep problems with increasing joint site count. Women, obese individuals and those with comorbidities had higher levels of fatigue. No differences were seen by arthritis type. In the model adjusting only for personal and health characteristics having 2-3 sites or more was significantly associated with higher levels of fatigue. When pain severity was added to the model the coefficients for 2-3 and 4-7 sites were no longer significant, and for the 8+ sites group was decreased by 67.4% (β=5.7, 95% CI: 0.5-9.1) suggesting that the effect of joint count on fatigue was fully mediated by pain severity for <8 joints and partially mediated for 8+ joint sites group. Adding sleep problems to the model, further decreased the coefficient for 8+ sites by 15.8% (β=4.8, 95% CI: 0.5-9.1).
Conclusion: The results underscore the high frequency of multiple joint site involvement among people with arthritis, as well as the importance of joint site count for pain severity, sleep problems, and fatigue. The findings confirm that the effect of number of joint sites on fatigue is mediated through pain severity and sleep problems, and indicate at least some direct effect of widespread joint involvement on fatigue. These findings together with the similarities for the different types of arthritis point to the need to pay attention to the number of joint sites affected for all types of arthritis in strategies aiming to reduce the impact of fatigue.
Disclosure:
M. Canizares,
None;
E. M. Badley,
None.
ACR Meeting Abstracts - https://acrabstracts.org/abstract/multisite-joint-pain-and-fatigue-the-role-of-pain-severity-and-sleep-problems-in-adults-with-arthritis/