Characterization of sleep disturbance in established rheumatoid arthritis patients: exploring the relationship with central nervous system pain regulation

Background: To characterize sleep disturbance in patients with established rheumatoid arthritis (RA) and explore the relationship between sleep and mechanisms of central nervous system pain regulation. Methods: Forty-eight RA participants completed wrist-worn actigraphy monitoring and daily sleep diaries for 14 days to assess sleep-wake parameters. Participants underwent quantitative sensory testing to assess pressure pain thresholds, temporal summation, and conditioned pain modulation. Data were analyzed using descriptive statistics, Spearman’s correlation, and multivariable median regression analyses. Results: Median actigraphy and sleep diary derived sleep duration was 7.6 h (interquartile range (IQR) 7.0, 8.2) and 7.1 h (IQR 6.7, 7.6), respectively. Actigraphy based sleep fragmentation (rho = 0.34), wake after sleep onset (rho = 0.36), and sleep efficiency (rho = -0.32) were each related to higher temporal summation values in unadjusted analyses, but these relationships did not persist after controlling for age, body mass index, disease duration, and swollen joint count. No significant relationships were observed between sleep with pressure pain thresholds and conditioned pain modulation. Conclusion: Actigraphy and sleep diary monitoring are well tolerated in established RA patients. Future investigations should include both subjective and objective assessments, as they may provide information relating to different components and mechanisms.