The relationship between sleep and pain in people with lower limb osteoarthritis and chronic low back pain

Abstract

People with lower limb osteoarthritis (OA) and chronic low back pain (LBP) commonly have insomnia symptoms, which are associated with worse pain intensity. Inflammation has been proposed to contribute in the sleep-pain relationship. This thesis addressed two major gaps in the literature: whether insomnia treatments can improve sleep and pain in people with comorbid insomnia and chronic musculoskeletal pain; and whether c-reactive protein (CRP), a marker of inflammation, has an independent contribution in the insomnia-pain relationship. Study one was a systematic review of 24 randomized controlled trials (RCT) on sleep interventions to determine their effects on OA and LBP. Face-to-face cognitive behavioural therapy for insomnia (CBT-i) and sleep medications were effective guideline-recommended treatments in reducing pain for people with chronic LBP, and sleep for people with chronic LBP, or OA. Study two determined if an online digital CBT-i can be feasibly implemented within an RCT design in people with comorbid insomnia and LBP, in twin and singleton populations (n=98). For digital CBT-i to be feasible for people with LBP, better strategies than the ones present in the study need to be implemented to improve adherence, and follow-up. Study three evaluated the associations between insomnia, CRP and LBP in a large cross-sectional database study (n=30,669). People with insomnia had twice the odds of reporting chronic LBP, but only a small association between CRP and LBP and no association between CRP and insomnia was found. Study four evaluated the independent longitudinal associations of insomnia, inflammation and chronic musculoskeletal pain in a Norwegian cohort (n=5,926) with eight years follow up. People with chronic musculoskeletal pain had 38-73% higher risk of developing insomnia, but people with insomnia did not have an increased risk of developing chronic musculoskeletal pain. CRP did not have an independent contribution in the insomnia-pain relationship.