Do comorbidities predict pain and function in knee osteoarthritis following an exercise intervention, and do they moderate the effect of exercise? Analyses of data from three randomized controlled trials

Abstract

Background Although exercise is a core treatment for people with knee osteoarthritis (OA), it is currently unknown whether those with additional comorbidities respond differently to exercise than those without. We explored whether comorbidities predict pain and function following an exercise intervention in people with knee OA, and whether they moderate response to: exercise versus no exercise; and enhanced exercise versus usual exercise‐based care. Methods We undertook analyses of existing data from three randomized controlled trials (RCTs): TOPIK (n = 217), APEX (n = 352) and Benefits of Effective Exercise for knee Pain (BEEP) (n = 514). All three RCTs included: adults with knee pain attributable to OA; physiotherapy‐led exercise; data on six comorbidities (overweight/obesity, pain elsewhere, anxiety/depression, cardiac problems, diabetes mellitus and respiratory conditions); the outcomes of interest (six‐month Western Ontario and McMaster Universities Arthritis Index knee pain and function). Adjusted mixed models were fitted where data was available; otherwise linear regression models were used. Results Obesity compared with underweight/normal body mass index was significantly associated with knee pain following exercise, as was the presence compared with absence of anxiety/depression. The presence of cardiac problems was significantly associated with the effect of enhanced versus usual exercise‐based care for knee function, indicating that enhanced exercise may be less effective for improving knee function in people with cardiac problems. Associations for all other potential prognostic factors and moderators were weak and not statistically significant. Conclusions Obesity and anxiety/depression predicted pain and function outcomes in people offered an exercise intervention, but only the presence of cardiac problems might moderate the effect of exercise for knee OA. Further confirmatory investigations are required.

3D Kinematics and Decision Trees to Predict the Impact of a Physical Exercise Program on Knee Osteoarthritis Patients

“…Indeed, the vast majority of studies on predictive models in knee OA populations have focused on identifying risk factors to help predict disease progression [11][12][13]. Notably, age, body mass index (BMI), or radiographic grading appeared to play an important role, and thus they were mainly used as the only possible predictors in the few studies which actually predicted the impact of physical exercise programs on knee OA [14,15].…”

Associations between comorbidities and immediate and one-year outcomes following supervised exercise therapy and patient education – A cohort study of 24,513 individuals with knee or hip osteoarthritis

“…Still, selection bias cannot be ruled out as participants in GLA:D ®® is a selected group seeking physiotherapy for their OA symptoms where those with severe comorbidities may be detained by physicians from exercise therapy due to restrictions or contraindications for exercise therapy 33 , or referred to other suitable therapies, e.g., cardiac or pulmonary rehabilitation programs. This may partly be reflected by fewer individuals reporting having comorbidities and a much lower prevalence of comorbidities such as pulmonary disease and depression than previously reported from primary care in the United Kingdom 2,11 . Some of these discrepancies might be a consequence of different groupings and definitions of conditions but suggest that participants in GLA:D ®® overall are healthier than individuals with OA in general, which might partially explain the absence of associations between comorbidities and outcomes after exercise therapy in the present study.…”

“…To our knowledge, this is the first study to investigate the association of a large number of possible comorbidities with health outcomes after an exercise and education program for individuals with knee and hip OA. Only Legha et al has recently made the attempt, however only included six different conditions with a smaller sample size and without investigating the association of different combinations of comorbidities 11 . They found an association between obesity and anxiety/depression with patient-reported pain and function after exercise therapy at 6 months follow-up, but no associations between diabetes, cardiac or pulmonary conditions, or pain in other body parts and the outcomes.…”

“…It is important to determine if outcomes from exercise therapy are suboptimal in individuals with OA and specific comorbidities or combinations of comorbidities in order to optimize outcomes by tailoring treatment programs specific to the needs of different subgroups. Only one recent study, limited by including just six comorbidities and a relatively low number of individuals with some of the comorbidities, has investigated if the presence of comorbidities was associated with pain and function outcome after exercise therapy 11 . They found that obesity and anxiety/depression were predictive of both pain and function outcomes, whereas estimates for pulmonary conditions and diabetes were imprecise due to few cases, precluding any clear interpretations.…”

Wireless Motion Sensors—Useful in Assessing the Effectiveness of Physiotherapeutic Methods Used in Patients with Knee Osteoarthritis—Preliminary Report

“…However, a question arises whether the different kinesitherapy techniques are equally quick and efficient in improving JPS. Most researchers agree that the earliest positive effects of a specific exercise of OAK may be observed following a four-week exercise regimen [28,29]. Still, it is not known whether other therapy techniques, which do not necessarily require active patient participation and last less than four weeks in duration, could also have a significantly positive impact on knee JPS.…”