Poor Sleep Quality Is Independently Linked to Pain

Poor sleep quality and comorbidities are independently associated with pain, a new study found.¹

“This study highlights the importance of the evaluation of sleep and comorbidities such as fibromyalgia, sleep apnea, depression, and anxiety in patients with [rheumatoid arthritis] and [psoriatic arthritis] who present intense symptoms, especially in patients with no objective signs of an active disease,” investigators, by Lauri Weman, MD, from the University of Eastern Finland, wrote.

About 41.5% of women and 35.3% of men in the general population endure sleep problems. Sleep disturbances are even more common in people with rheumatoid arthritis (RA) and psoriatic arthritis (PsA), with a prevalence of 50 – 75% and 45-85%, respectively.

Yet previous studies showed measures of RA disease activity have a weak association with sleeping difficulties.² Despite this, patients with RA who report sleep difficulties also report increased pain, worse mood, tender joint counts, and general tenderness more often than patients without sleep difficulties.¹

In contrast, studies on PsA found joint counts, the number of enthesitides, and the levels of CRP and ESR correlated significantly with sleep issues. For RA research, however, the swollen joints were similar in patients with and without sleep issues.

Investigators aimed to assess whether poor sleep and comorbidities were linked to high symptom levels of pain, patient global assessment, and fatigue in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA). They conducted a nationwide cross-sectional study, leveraging clinical data from The Finnish Rheumatology Quality Register between January 1, 2021 and September 1, 2022.

Patients self-reported sleep as either “good” (little or no difficulties) or “poor” (great difficulties or can’t sleep). The team collected comorbidity data from national registers.

The register included 13512 patients with RA and 3636 patients with PsA. However, sleep status was only available for 6052 with RA and 1861 with PsA. The common comorbidities for RA and PsA, in order of prevalence, were depressive disorders (12% vs 17%), sleep apnea (11% vs 17%), anxiety disorders (7% vs 12 vs), and fibromyalgia (3% vs 4%).

Among RA patients, 84% reported good sleep and 16% reported poor sleep. As for PsA patients, 78% reported good sleep and 22% reported poor sleep.

Patients were more likely to report good sleep over poor sleep if they were slightly older and female. Median objective disease activity values of swollen joint count on 66 joints (SJC66), tender joint count on 68 joints (TJC68), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), disease activity score 28 (DAS28), Clinical Disease Activity Index for Psoriatic Arthritis (cDAPSA), and Dr global were low and similar in RA and PsA patients regardless of whether they had poor or good sleep. However, when adjusted for age and gender, there were statistically significant differences.

After adjusting for age, gender, disease activity, and pain catastrophizing, patients with poor sleep had significantly greater median Visual Analogue Scale for pain, fatigue, and patient global assessment. Patients with poor sleep also had greater high pain catastrophizing scores and median Health Assessment Questionnaire, compared to patients with good sleep.

Patients with sleeping issues but no swollen joints on SJC66 had about 3 times greater pain, fatigue, and patient global activity (P < .001). Patients with poor sleep also reported greater HAQ and pain catastrophizing scores.

Among patients with RA with no swollen joints, 92% who reported good sleep and 80% who reported poor sleep were in remission by DAS28 (P < .001). As for patients with PsA, 92% with good sleep and 58% with poor sleep had remission or low disease activity by cDAPSA (P < .001).

A regression analysis showed poor sleep was independently associated with more pain symptoms in RA (20; 95% confidence interval [CI], 18 – 22) and PsA (23; 95% CI, 19 – 26), followed by comorbid fibromyalgia, depression in RA, and sleep apnea in PsA.

The team wrote the sleep measurement tool limited the results since the data was not collected from a large research questionnaire.

“‘Poor’ sleep quality and comorbidities are independently associated with pain,” investigators concluded. “Patient’s sleep status is important to know especially in patients with severe symptoms without objective disease activity.”

References

1. ^{Weman L, Salo H, Kuusalo L, et al. Intense symptoms of pain are associated with poor sleep, fibromyalgia, depression and sleep apnea in patients with rheumatoid arthritis and psoriatic arthritis. A register based study. Joint Bone Spine. Published online May 23, 2024. doi:10.1016/j.jbspin.2024.105744}
2. ^{Løppenthin K, Esbensen BA, Jennum P, Østergaard M, Tolver A, Thomsen T, et al. Sleep quality and correlates of poor sleep in patients with rheumatoid arthritis. Clin Rheumatol. 2015;34:202939.}