A comparative study between rheumatoid arthritis and osteoarthritis regarding association of insomnia with disease status

Abstract

Abstract Background Sleep disturbance is closely related to inflammation and pain. Good sleep quality is essential for patients’ psychological and physical states as well as their quality of life. The aim of this study was to detect how insomnia as a major sleep disturbance could add to the disease burden in rheumatoid arthritis (RA) and osteoarthritis patients (OA) and to determine the predictor parameters in each of them in order to orient the rheumatologist to this unnoticed symptom that could adversely affect the patients’ life. This study included: 20 RA patients, 20 primary knee OA patients together with 20 healthy controls. RA disease activity was assessed by the disease activity score (DAS-28). All participants were assessed for sleep disturbances by the Athens Insomnia Scale, quality of life (QoL) using the short form QoL (SF-36 QoL) scale, depression by the Beck depression inventory (BDI), and functional disability by the Health Assessment Questionnaire Disability Index (HAQ-DI). OA patients were assessed by the Knee OA Flare Up Score (KOFUS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Radiological evaluation for RA patients was done by the Simple Erosion Narrowing Score, while the Kellgren and Lawrence (K-L) radiological grading system was used for OA patients. Results Insomnia was found in 75% of the studied RA patients, 25% of the studied OA patients and none of the healthy control with significant difference (P < 0.001). Significant correlations of the insomnia scale with the number of tender and swollen joints (r = 0.66, 0.76 respectively and p = 0.001 both), DAS-28 (r = 0.71, P < 0.001), anti-CCP antibodies titre (r = 0.53, p = 0.02) and the BDI (r = 0.65, p = 0.002) among RA patients were found. Correlations among OA patients occurred with morning stiffness duration (r = 0.69, P = 0.001), number of affected joints (r = 0.81, P = 0.001), the BDI scale (r = 0.51, P = 0.02), the WOMAC index (r = 0.57, P = 0.009), the KOFUS score (r = 0.76, p < 0.001) and the K-L score (r = 0.67, P = 0.001). Linear regression analysis indicated that the predictors for insomnia in RA were DAS-28 and the BDI, while in OA were the number of affected joints and the KOFUS score. Conclusions Insomnia is a disease burden especially in RA patients being one of the leading causes of depression and is greatly affected by the disease activity. In general the burden of insomnia is much less in OA except in severe cases with markedly affected joints. Rheumatologists should be aware of this disorder that could affect patients’ health, mood, and functional activity.

Keywords

• Rheumatoid arthritis
• Osteoarthritis
• Sleep disturbance
• Insomnia
• Depression