Background/Purpose:

Sleep quality is an important aspect of health and well-being and the Outcome Measures in Rheumatology Clinical Trials group has identified sleep quality as a key concern for rheumatoid arthritis (RA) patients¹. Patient reported sleep-disturbance is included in the RAID (RA Impact of Disease) score, but not in many other core patient reported outcomes (PROs) and is rarely reported in clinical trials.  The aim of this study was to assess self-reported sleep disturbance in a large sample of patients from a population based RA registry and identify factors associated with self-reported sleep disturbance.

Methods:

In a population based RA registry in Oslo, Norway, 868 patients aged 20-79 years (mean (SD) age 59.9 (12.3) years, disease duration 13.0 (10.8) years, 77.1% females) responded to a mailed questionnaire in 2009 (response rate 60.6%). 844 patients answered the numeric rating scale (NRS) on sleep disturbance due to RA (part of the RAID questionnaire) within the last week, and reported use of benzodiazepine like sleeping drugs (zopiclone/zolpidem = z-hypnotics) and other medications used in the treatment of RA. Other PROs included 100mm visual analogue scales (VAS) for pain, fatigue and patient global disease activity, HAQ (0-3, 3 worst), SF-36 with physical (PCS) and mental (MCS) component scores (0-100, 0=worst), RA Disease Activity Index (RADAI, 0-10, 10 worst) and RAID score (0-10, 10=extreme/very poor). Multivariate linear regression analyses were used to identify factors independently associated with sleep disturbance (0-10 NRS, 10=extreme sleep disturbance) and adjusted for age and disease duration.

Results:

Table 1.  Clinical findings in females and males

Multivariate linear regression analyses, adjusted for age and disease duration, with sleep disturbance assessed by NRS(0-10) as dependent variable, identified significant independent associations with female gender (B=0.40, 95% CI 0.06, 0.74), HAQ (B=0.40, 95% CI 0.13, 0.67), RADAI (B=0.42, 95% CI 0.27, 0.57), VAS pain* (B=0.15, 95% CI 0.041, 0.27), VAS fatigue* (B=0.18, 95% CI 0.11, 0.25) and MCS* (B= -0.52, 95% CI -0.65, -0.38). *per 10 unit change.

Use of z-hypnotics was significantly associated with MCS, PCS, HAQ, RADAI, RAID, NRS sleep disturbance, VAS pain/fatigue/patglob (all p<0.001), and disease duration (p=0.03).

Conclusion:

Sleep disturbance in RA is to a higher degree reported by females, and is independently associated with pain, fatigue and worse mental and physical function. Sleep is independently associated with RA disease impact and therefore merits attention in clinical care.

(1) Kirwan JR, Newman S, Tugwell PS, Wells GA. Patient Perspective on Outcomes in Rheumatology A Position Paper for OMERACT 9. J Rheumatol 2009;36(9):2067-70.