Central pain mechanisms predict physical inactivity at 1-year in individuals with knee pain

Habib, M.U.; Smith, S.L.; Chaplin, W.J.; Millar, B.; McWilliams, D.F.; Walsh, D.A.

Abstract

Purpose: Pain is the primary clinical manifestation in individuals with osteoarthritis (OA). It is an unpleasant and distressing experience, particularly during weight-bearing activities, inhibiting activity, and reducing quality of life. Two groups of mechanisms cause OA pain: peripheral (local joint pain from joint pathology) and central (severely worsened pain due to brain and spinal cord processing of peripheral nociceptive inputs). Each contributes to varying extents at different times to an individual’s OA pain. Pain and physical inactivity are often treated by discrete interventions, but in reality are tightly integrated. Several traits linked to central pain processing, such as catastrophising, depression and fatigue, have been independently linked to physical inactivity. This study aimed to explore cross sectional and longitudinal associations between central pain mechanisms and physical inactivity in individuals with knee pain.
Methods: This study is an analysis of the first 5,000 participants with validated questionnaire data, aged ≥40 who completed FRAIL in the Investigating Musculoskeletal Health and Wellbeing (IMH&W) cohort (n= >8,570), based in the East Midlands region of the UK. Participants completed a questionnaire at baseline and 1-year later, including participant characteristics and 0 to 10 numerical rating scale (NRS) of pain in the most troublesome joint in the past 4-weeks. Central pain Mechanisms Trait (CMT) was measured using the Central Aspects of Pain in the Knee (CAP-Knee) questionnaire, comprising 8-items addressing anxiety, depression, catastrophising, neuropathic-like pain, fatigue, sleep disturbance, pain distribution and cognitive impact, giving a maximum total score of 16. Self-reported physical activity was measured using the FiND questionnaire item, through which participants report their level of physical activity as either regular (at least 2-4 hours a week) or none/mainly sedentary. Associations were explored using logistic regression models. Data are presented as median (interquartile range), odds ratios (OR), and 95% confidence intervals.
Results: 2473 participants completed the FRAIL, of whom 722 participants reported knee as their most troublesome joint and an NRS pain ≥1, of whom 407 participants had self-reported physical activity data also at 1-year. The 722 participants had a median (IQR) age 72 (65-77), with a BMI of 28.08 (24.82-31.64), 55% were female, and 70% reported being regularly physically active at baseline. Median (IQR) CAP-Knee was 8 (5-11) and NRS pain was 6 (4-8). Individuals who did not complete follow-up data had significantly higher baseline NRS pain, CAP-Knee, lower BMI, and were more sedentary. For each unit increase in NRS pain or CAP-Knee at baseline, participants were more likely to be sedentary at baseline (NRS OR=1.25 (95%CI 1.16, 1.36), P<0.001; CAP-Knee OR=1.20 (95%CI 1.14, 1.26), P<0.001) and follow-up (NRS OR=1.17 (95%CI 1.05, 1.30), P=0.004; CAP-Knee OR=1.15 (95%CI 1.08, 0.93), P<0.001). When adjusted for potential confounders age, sex, BMI, knee replacement the association between baseline CAP-Knee and baseline physical activity remained significant (aOR=1.19 (95%CI 1.13, 1.25) P<0.001, Table 1), and significantly predicted 1-year physical inactivity (aOR=1.13, (95%CI 1.06, 1.21) P<0.001, Table 2). The depression item was the only CAP-Knee item significantly associated with physical activity levels in both cross-sectional and longitudinal analyses. Baseline fatigue was significantly associated with baseline physical activity.
Conclusions: Higher scores for baseline central pain mechanisms were associated with lower baseline physical activity and predicted 1-year physical inactivity. Our data highlight the integration between pain and physical activity. The observed associations between central pain mechanisms and physical activity might indicate shared neurological mechanisms, and central pain mechanisms might also act as barriers to increasing activity. Specific central mechanisms, particularly depression and fatigue, might be important targets to help improve physical activity in people with knee pain.

Citation

Habib, M., Smith, S., Chaplin, W., Millar, B., McWilliams, D., & Walsh, D. (2022). Central pain mechanisms predict physical inactivity at 1-year in individuals with knee pain. Osteoarthritis and Cartilage, 30(Sup 1), S379. https://doi.org/10.1016/j.joca.2022.02.511

• Journal Article Type: Meeting Abstract
• Conference Name: Osteoarthritis Research Society International (OARSI)
• Conference Location: Berlin
• Acceptance Date: Apr 1, 2022
• Online Publication Date: Mar 28, 2022
• Publication Date: 2022-04
• Deposit Date: May 31, 2022
• Publicly Available Date: Jul 27, 2023
• Journal: Osteoarthritis and Cartilage
• Print ISSN: 1063-4584
• Peer Reviewed: Peer Reviewed
• Volume: 30
• Issue: Sup 1
• Pages: S379
• DOI: https://doi.org/10.1016/j.joca.2022.02.511
• Keywords: Orthopedics and Sports Medicine; Biomedical Engineering; Rheumatology
• Public URL: https://nottingham-repository.worktribe.com/output/8307894
• Publisher URL: https://www.oarsijournal.com/article/S1063-4584(22)00545-3/fulltext#articleInformation
• Related Public URLs: https://www.sciencedirect.com/science/article/abs/pii/S1063458422005453