Short-term Improvement in Insomnia Symptoms Predicts Long-term Improvements in Sleep Pain and Fatigue in Older Adults with Co-Morbid Osteoarthritis and Insomnia

摘要

In a primary care population of 367 older adults (age 60+) with osteoarthritis (OA) pain and insomnia, we examined the relationship between short-term improvement in sleep and long-term sleep, pain and fatigue outcomes through secondary analyses of randomized controlled trial data. Study participants, regardless of experimental treatment received, were classified as either Improvers (≥30% baseline to 2-month reduction on the Insomnia Severity Index [ISI]) or Non-Improvers. After controlling for treatment arm and potential confounders, Improvers showed significant, sustained improvements across 18 months compared to Non-Improvers in Pain Severity (p<.001, Adjusted Mean Difference = −0.51 [95% Confidence Interval: −0.80, −0.21]), Arthritis Symptoms (p<.001, 0.63 [0.26, 1.00]), and Fear Avoidance (p=.009, −2.27 [−3.95, −0.58]) but not in Catastrophizing or Depression. Improvers also showed significant, sustained improvements in ISI (p<.001, −3.03 [−3.74, −2.32]), Pittsburgh Sleep Quality Index Total (p<.001, −1.45 [−1.97, −0.93]) and General Sleep Quality (p<.001, −.28 [−.39, −.16]) scores, Flinders Fatigue Scale (p<.001, −1.99 [−3.01, −0.98]), and Dysfunctional Beliefs about Sleep (p=.037, −2.44 [−4.74, −0.15]), but no improvements on the Functional Outcomes of Sleep Questionnaire or the Epworth Sleepiness Scale. We conclude that short-term (2-month) improvements in sleep predicted long-term (9- and 18-month) improvements for multiple measures of sleep, chronic pain, and fatigue. These improvements were not attributable to non-specific benefits for psychological well-being such as reduced depression. These findings are consistent with benefits of improved sleep for chronic pain and fatigue among older persons with osteoarthritis pain and co-morbid insomnia if robust improvements in sleep are achieved and sustained.