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
1Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
2Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
3Rheumatology Division, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
4Institute 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.
5Center for Complementary and Integrative Medicine; Division of Rheumatology, Allergy & Immunology; Tufts Medical Center, Boston, MA, USA.
6Nutrition, 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