Disease activity and sleep quality in rheumatoid arthritis: a deeper look into the relationship

Objectives: This study looks deeper into the relationship between rheumatoid arthritis (RA) disease activity and distinct dimensions of sleep quality. Methods: The Pittsburgh Sleep Quality Index (PSQI) was administered to a cohort of 147 RA patients. Health-related quality of life (HRQoL) and fatigue were measured with the SF-12 and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) instruments, respectively, whereas RA activity was determined with the Disease Activity Score 28 joints (DAS28). Ethical approval for the study and informed consent from the participants were obtained. Results: Most patients were females (78.2%), and the mean age of the entire sample was 63.7 years. Most participants (77.6%) were poor sleepers (i.e. PSQI ≥ 5) who suffered from fatigue more than good sleepers (FACIT-F: 21.6 vs. 39.3, p < 0.001). Overall sleep quality correlated, in the expected directions, with disease activity (Spearman's rho = 0.87, p < 0.001), physical health (-0.66, p < 0.001), mental health (-0.71, p < 0.001), and fatigue (0.87, p < 0.001). PSQI and its component scores differed across patient subgroups with increasing RA activity, even after adjusting for confounding variables. Conclusion: RA disease activity distinctly affects sleep quality, and given the already demonstrated importance of good sleep, this 'deeper look' might contribute to the effort to improve HRQoL in RA patients.