Study data published in Arthritis Care & Research found no association between daily walking levels and knee pain in patients with mild to moderate, symptomatic knee osteoarthritis (OA).
Investigators conducted a longitudinal observational study of patients with clinical knee OA to assess the correlation between daily physical activity and knee pain. Sociodemographic characteristics, clinical disease severity, and pain levels were assessed at baseline. Follow-up assessments were conducted every 3 months for 3 years to capture daily physical activity and pain levels. Physical activity was measured with an accelerometer, which provided average per day step counts. Pain was measured with 2 patient-administered questionnaires: the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the P4 pain scale. The KOOS pain survey was administered in the week preceding accelerometer wear to reflect pain levels before physical activity measures, and the P4 pain scale measure was recorded concurrently on physical activity days. Mixed effects models were employed to assess the relationship between KOOS pain and P4 pain scores and physical activity.
The final study cohort comprised 59 participants, of whom 48 were women. The average body mass index was 28.1 kg/m2, and the average age of the participants was 61.1 years. All patients had a diagnosis of clinical, symptomatic knee OA of mild to moderate severity. Analyses incorporated a total of 513 observations from study participants.
Age and body mass index were inversely associated with physical activity (both P <.001). Physical activity during spring and fall (P =.002) and winter (P <.001) were associated with lower levels of physical activity compared with summer. Neither KOOS pain scores (P =.717) nor P4 pain scores (P =.264) were associated with physical activity. The KOOS pain and P4 pain scales demonstrated strong but imperfect agreement with one another (R2 =.579), supporting the use of multiple measures to capture all components of patient pain.
In this study cohort, knee pain was not associated with daily walking levels. To augment daily walking levels in patients with knee OA, investigators recommended additional research on patient barriers to physical activity, such as depressive symptoms, fatigue, and perceived self-efficacy.
Brisson NM, Gatti AA, Maly MR. Pain is not associated with steps per day in persons with mild-to-moderate, symptomatic knee osteoarthritis—a mixed models analysis of multiple measurements over 3 years [published online March 6, 2019]. Arthritis Care Res. doi:10.1002/acr.23842