Background Osteoarthritis (OA) particularly knee OA, is a common cause of pain and disability among older adults. Sleep quality is a major concern among persons with OA, with 60% of patients reporting nocturnal pain. Pain interferes with sleep and disturbed sleep lowers the pain threshold. Pain initiates and exacerbates sleep disturbance, whereas disturbed sleep maintains and exacerbates pain.
Objectives To explore the potential impact of improving sleep by cognitive behavioural therapy (CBT) on OA pain and functional outcomes.
Methods 118 patients, mean age 68.2 years with primary knee OA were recruited in this 12-week randomized controlled trial. Eligibility criteria included persons with both clinically significant persistent knee pain defined as >40 mm on a 100-mm visual analogue scale (VAS)/daily pain and clinically significant insomnia defined by self-reported sleep difficulties (trouble falling asleep, difficulty staying asleep, waking up too early ect.) at least 3 nights/week during the past month. Exclusion criteria included rheumatoid arthritis, obstructive sleep apnoea, any primary sleep disorder, dementia and cancer. Patients were randomly assigned to a combined CBT and usual care intervention group (n=59) or to a usual care control group (n=59). The CBT consisted of twelve weekly sessions on pain and sleep management rationale, sleep hygiene education, stimulus control and sleep restriction. Primary outcome measures included pain reduction and improvement in sleep. Insomnia was assessed using the sleep diary and Insomnia Severity Index (ISI) total item score. Secondary outcomes included improvements in physical function scores assessed by using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and activities of daily living (ADL). Ancillary outcomes included cognitive function assessed by the mini mental state examination (MMSE), depression assessed by the geriatric depression scale (GDS) and medication use.
Results CBT subjects as compared to the usual care group reported significantly improved sleep and significantly reduced pain after treatment. In the intervention group there was a statistically significant reduction in insomnia severity (score range 0–27) compared to the control group (mean treatment difference = −1.85, 95% CI = −2.73 to −0.97; P<0.001). Post-treatment there was a clinically relevant reduction in the intervention group compared to the control group for knee pain. The mean difference between treatment arms (95% CI was 9.9 (1.8 to 18.0); p<0.005. The intervention group had better functioning than participants continuing usual care group as assessed by WOMAC-function scores and ADLs. Post-treatment MMSE and GDS scores showed improvement in the intervention group compared to the placebo group. A positive correlation was found between insomnia severity and knee pain, r=0.585; p<0.001.
Conclusions The study indicates that CBT was effective for older adults with OA pain and insomnia. CBT improved functional outcomes and depression. The findings, support the hypothesis that improving sleep, per se, in patients with OA may be analgesic”, such that perceived pain is reduced without being specifically targeted. These results further suggest that techniques to improve sleep, such as CBT should be considered as additions to the therapeutic armamentarium for pain management in OA.
Disclosure of Interest None declared