Sleep problems and related symptoms occur in 54% to 70% of patients with rheumatoid arthritis (RA).1 Poor sleep quality has been associated with disease activity and health-related quality of life (HRQoL) in RA; however, this association remains poorly understood despite being clearly shown to exist. In a study published in Expert Review of Pharmacoeconomics and Outcomes Research, researchers looked further into the relationship between RA disease activity and sleep quality and into treatment changes that may improve quality of sleep and HRQoL in RA.
Measuring Sleep Quality, Fatigue, HRQoL, and Disease Activity
In this cross-sectional study, researchers evaluated data collected from 147 adults with RA who were visiting primary care facilities in Athens, Greece, between January and April 2017.1 All patients completed self-reported surveys and questionnaires related to sleep quality, fatigue, RA symptoms, and HRQoL.
Investigators assessed sleep quality using the Pittsburgh Sleep Quality Index (PSQI): an instrument used to differentiate between good vs poor sleepers. The PSQI inquires about 7 dimensions of sleep quality: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, sleep medication use, and daytime dysfunction. Researchers stated that the PSQI is reliable at determining risk factors and the prevalence of poor sleep quality in a wide range of populations, including individuals with RA.
Fatigue and HRQoL
Investigators measured fatigue and HRQoL using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) and Short Form 12, respectively. The FACIT-F scale uses 13 statements allowing patients to describe fatigue and its effect on daily activities and function, and like the PSQI, it has been useful to assess fatigue in various populations, including RA, according to researchers. The Short Form-12 has 12 items to evaluate the association between general HRQoL and RA pain severity.
RA Disease Activity
Researchers measured RA activity using the Disease Activity Score 28 joints (DAS28). The DAS28 score provides an absolute indication of RA disease activity on a scale of 0.49 to 9.07, with values greater than 5.1 corresponding to high disease activity, values between 3.2 and 5.1 corresponding to moderate activity, values between 2.6 and 3.2 corresponding to low activity, and values less than 2.6 corresponding to remission.
A Summary of the Findings
The majority of patients in this study were women (78.2%), and the mean age of the sample as a whole was 63.68±10.88 years.1 Most patients had at least one comorbidity (83.7%), mostly hypertension/dyslipidemia (33.3%).1 The most common treatments were synthetic disease-modifying antirheumatic drug monotherapy (45.6%) and combined synthetic disease-modifying antirheumatic drug monotherapy and biologic treatment (34.7%).1 RA activity as measured by DAS28 was extremely high in 13.6% of the sample, moderate in 36.7%, low in 27.2%, and in remission in 22.5%.1
The mean PSQI score of 10.24±4.58 revealed that poor overall sleep quality was highly prevalent in this sample — much of which was affected by sleep disorders (2.12±0.78).1 The majority of patients were poor sleepers (n=114) who suffered from fatigue more than good sleepers (mean FACIT-F: 21.66±8.26 vs 39.28±, respectively; P <.001).1 Poor sleepers had moderate disease activity (mean DAS28=3.8±1.05) whereas in good sleepers, RA was in remission (DAS28=2.22±0.4).1 Compared with good sleepers, poor sleepers had worse physical and mental health. Poor sleep quality was also associated with medication use.
After adjusting for confounding variables, including fatigue, treatment type, and disease duration, RA disease activity remained a key predictor of overall sleep quality, subjective sleep quality (P =.014), sleep duration (P <.001), sleep disorders (P =.043), and use of sleep medications (P =.012).1
Addressing the Root Cause of Poor Sleep in RA
Researchers stated that fatigue is experienced almost universally in patients with RA and is a known confounder of sleep quality. Further, they stated that deteriorated physical and mental health have also been associated with poor sleep quality across all PSQI dimensions.
Though previous investigators used the PSQI in patients with RA, no prior investigators have studied the effect of confounding variables in individual sleep dimensions. Study researchers highlighted areas where physicians should focus attention to improve overall quality of sleep in patients with RA. For instance, patients with low sleep duration were found to be affected by RA disease activity, which indicates that physicians can make efforts to help these patients sleep for longer periods to improve overall sleep quality and HRQoL.
Researchers pointed out that the majority of patients in this study suffered from at least 1 other comorbidity, such as diabetes, hypertension, and osteoporosis, which may affect sleep quality; however, the PSQI did not associate any of these comorbidities with worsened sleep quality, which implies they may be outweighed by RA disease activity. Despite the lack of association between comorbidities and poor sleep quality in RA, researchers found that factors including fatigue, disease duration, and physical and mental health all contributed to poorer sleep quality.
In a 2018 study that assessed sleep quality in 95 patients with RA, it was revealed that poor sleep in RA may also be caused by pain. Of these patients, 56.8% reported nonoptimal sleep duration.2 Compared with those who reported optimal sleep duration, the group who reported poor sleep quality experienced higher median pain levels (95% CI, 2.3-6. vs 2.5; 95% CI, 2-3.5], respectively; P =.003).2 In addition, the multivariate regression analysis performed in the study revealed that higher intensity pain was associated with a reduced likelihood of optimal sleep (odds ratio=0.68; 95% CI, 0.47-0.98; P =.038).2 The researchers suggested that both sleep and pain assessments should be included in clinical assessment of RA, and that physicians working with these patients should be aware of these issues and consider pharmacologic and psychological interventions that may positively affect sleep quality.2
The study researchers concluded that results are consistent with those from other studies showing RA disease activity’s profound effect on sleep quality and that patients who experience RA and poor sleep may benefit from treatments addressing specific components of sleep that are affected the most. Therefore, study researchers encouraged physicians to assist patients with RA in improving their sleep quality so they can experience better HRQoL.
1. Kontodimopoulos N, Stamatopoulou E, Kletsas G, Kandili A. Disease activity and sleep quality in rheumatoid arthritis: a deeper look into the relationship. Expert Rev Pharmacoecon Outcomes Res. 2019:1-8
2. Grabovac I, Haider S, Berner C, et al. Sleep quality in patients with rheumatoid arthritis and associations with pain, disability, disease duration, and activity [published online October 9, 2018]. J Clin Med. 2018;7.