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Minimum Performance on Clinical Tests of Physical Function to Predict Walking 6,000 Steps/Day in Knee Osteoarthritis: An Observational Study
Author(s) -
Master Hiral,
Thoma Louise M.,
Christiansen Meredith B.,
Polakowski Emily,
Schmitt Laura A.,
White Daniel K.
Publication year - 2018
Publication title -
arthritis care and research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.032
H-Index - 163
eISSN - 2151-4658
pISSN - 2151-464X
DOI - 10.1002/acr.23448
Subject(s) - medicine , osteoarthritis , preferred walking speed , physical therapy , physical medicine and rehabilitation , accelerometer , test (biology) , observational study , gait , physical examination , computer science , surgery , biology , operating system , paleontology , alternative medicine , pathology
Objective Evidence of physical function difficulties, such as difficulty rising from a chair, may limit daily walking for people with knee osteoarthritis (OA). The purpose of this study was to identify minimum performance thresholds on clinical tests of physical function predictive to walking ≥6,000 steps/day. This benchmark is known to discriminate people with knee OA who develop functional limitation over time from those who do not. Methods Using data from the Osteoarthritis Initiative, we quantified daily walking as average steps/day from an accelerometer (Actigraph GT1M) worn for ≥10 hours/day over 1 week. Physical function was quantified using 3 performance‐based clinical tests: 5 times sit‐to‐stand test, walking speed (tested over 20 meters), and 400‐meter walk test. To identify minimum performance thresholds for daily walking, we calculated physical function values corresponding to high specificity (80–95%) to predict walking ≥6,000 steps/day. Results Among 1,925 participants (mean ± SD age 65.1 ± 9.1 years, mean ± SD body mass index 28.4 ± 4.8 kg/m 2 , and 55% female) with valid accelerometer data, 54.9% walked ≥6,000 steps/day. High specificity thresholds of physical function for walking ≥6,000 steps/day ranged 11.4–14.0 seconds on the 5 times sit‐to‐stand test, 1.13–1.26 meters/second for walking speed, or 315–349 seconds on the 400‐meter walk test. Conclusion Not meeting these minimum performance thresholds on clinical tests of physical function may indicate inadequate physical ability to walk ≥6,000 steps/day for people with knee OA. Rehabilitation may be indicated to address underlying impairments limiting physical function.