Association Between Objective Sleep and Clinical Outcomes in Older Adults With Low Back Pain Receiving Physical Therapy Care: A Secondary Analysis of a Responsiveness Study.

Abstract

Sleep seems to be associated with worse low back pain (LBP) outcomes in older adults; however, studies investigating the association of objective sleep with future changes in LBP outcomes are lacking. The objectives of this study are as follows: (a)to investigate the association between objectively measured sleep with changes in clinical outcomes in older adults with LBP receiving physical therapy care and (b)to examine the cross-sectional association between sleep and pain catastrophizing. This was a prospective cohort study. We recruited older adults (≥60years old) with chronic LBP undergoing physical therapy treatment. At baseline, we assessed participants' sleep (actigraphy for 10-14days), pain intensity, disability, pain catastrophizing, and covariates. After 8weeks, we reassessed pain intensity, disability, and self-perceived recovery. We ran linear regression models and Spearman coefficient tests. Fifty-eight participants were included, and 51 completed follow-up assessments (60.8% women; mean age 70.1 ± 5.6years). We found no associations between sleep quantity and efficiency with changes in pain intensity, disability, and self-perceived recovery after 8weeks of physical therapy care. We found a correlation between sleep fragmentation and pain catastrophizing (r = .30; 95% confidence interval: [.03, .54]). Objective sleep quantity and efficiency may not be associated with changes in LBP outcomes after physical therapy care in older adults. Among the sleep domains evaluated, sleep fragmentation may be the sleep domain with the strongest association with pain catastrophizing. Significance/Implications: Objectively measured sleep might not be a prognostic factor for LBP improvement in older adults. Future studies should explore the association between sleep fragmentation and pain catastrophizing.