Prognostic Factors and Changes in Pain, Physical Functioning, and Participation in Patients With Hip and/or Knee Osteoarthritis: A Systematic Review.

Objective: This study aimed to systematically synthesize literature on prognostic factors of changes in either direction (ie, worsening or improvement) in pain, physical functioning, and participation in patients with knee and/or hip osteoarthritis (OA).

Methods: Studies included in two preceding reviews underwent full-text screening for inclusion in the current review. Additionally, an extensive literature search was conducted in five databases. Title/abstract screening was performed using an active learning program. Inclusion criteria comprised patients diagnosed with knee and/or hip OA, with the dependent variable assessing pain, physical functioning, or participation. Potential associated prognostic factors were measured as independent variables. The methodologic quality of studies was assessed with the Hayden criteria.

Results: A total of 31 studies were included in this systematic review. In patients with knee OA, pain worsening was associated with lower physical functioning (strong evidence) and with higher body mass index, ethnicity, and a higher comorbidity count (moderate evidence). Also, in patients with knee OA, pain improvement was associated with less pain at baseline (moderate evidence). In patients with knee and/or hip OA, worsening of physical functioning exhibited associations with higher body mass index, more pain, more hip pain, a higher comorbidity count, higher avoidance of activities (strong evidence), and ethnicity (moderate evidence). In patients with knee OA, improvement in physical functioning showed an association with higher vitality (moderate evidence). Regarding the remaining prognostic factors, there is weak, inconclusive, or inconsistent evidence for an association with the outcomes. In patients with hip OA, only weak evidence was found for three factors predicting a change in physical functioning.

Conclusion: This review encompasses prognostic factors associated with changes in either direction (ie, worsening or improvement) in pain, physical functioning, and participation. The results are consistent with other reviews. Future research should place a stronger emphasis on patients with hip OA and participation as an outcome.