Association between Pre-Intervention Physical Activity Level and Treatment Response to Exercise Therapy in Persons with Knee Osteoarthritis - An Exploratory Study.

Author: Chang AH1, Lee J2, Song J3, Price LL4,5, Lee AC5, Reid KF6, Fielding RA6, Driban JB5, Harvey WC5, Wang C5
Affiliation: <sup>1</sup>Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. <sup>2</sup>Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. <sup>3</sup>Rheumatology Division, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. <sup>4</sup>Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA, USA and Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA, USA. <sup>5</sup>Center for Complementary and Integrative Medicine; Division of Rheumatology, Allergy &amp; Immunology; Tufts Medical Center, Boston, MA, USA. <sup>6</sup>Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, USA.
Conference/Journal: ACR Open Rheumatol.
Date published: 2019 Apr
Other: Volume ID: 1 , Issue ID: 2 , Pages: 104-112 , Special Notes: doi: 10.1002/acr2.1013. Epub 2019 Apr 6. , Word Count: 249

Objective: Examine whether pre-intervention physical activity (PA) level is associated with achieving a positive treatment response of pain and/or function improvement after a 12-week exercise intervention in participants with knee osteoarthritis (OA).

Methods: We performed a secondary analysis of a randomized, single-blind comparative effectiveness trial showing similar treatment effects between Tai Chi mind-body exercise and standard physical therapy intervention for knee OA. Baseline PA was assessed by Community Healthy Activities Model Program for Seniors (CHAMPS) Questionnaire and, in a subsample, by tri-axial accelerometers. OMERACT-OARSI dichotomous responder criteria was used for clinically meaningful improvement at follow-up. Associations between baseline self-reported PA by CHAMPS and outcomes of responders vs. non-responders (reference group) were assessed using logistic regressions, adjusting for demographic covariates. We compared objectively-measured PA by accelerometry between responders vs. non-responders using Wilcoxon tests.

Results: Our sample consisted of 166 participants with knee OA who completed both baseline and 12-week post-intervention evaluations: mean age 60.7 year (SD 10.5), BMI 32.4 kg/m2 (6.9), 119 (72%) women, and 138 (83%) OMERACT-OARSI responders. Neither time spent in total PA (OR 1.00; 95% CI 0.96, 1.03) nor time in moderate-to-vigorous (MV) PA (OR 1.01; 95% CI 0.93, 1.09) at pre-intervention were associated with being a responder. Similar findings were observed in 42 accelerometry sub-cohort participants.

Conclusion: Pre-intervention PA level (subjective report or objective measurement) was not associated with whether an individual will achieve favorable treatment outcomes after a 12-week exercise intervention, suggesting that regardless of pre-intervention PA level, individuals will likely benefit from structured exercise interventions.

KEYWORDS: Exercise; OMERACT; Osteoarthritis; Physical Activity

PMID: 31763622 PMCID: PMC6857980 [Available on 2020-04-01] DOI: 10.1002/acr2.1013