Determinants of pain and functioning in knee osteoarthritis: a one-year prospective study.

This was a secondary analysis of a randomized trial, not a trial of the predictors themselves, so it can only show associations over time. The sample was selected from a trial requiring high pain, at least 40 of 100 on the WOMAC pain scale, and excluding severe psychiatric conditions, so it may not represent milder or more psychologically distressed knee osteoarthritis patients. Almost half of screened candidates, 47% or n=209, were excluded for too low pain, and only 19 patients had at least mild depressive symptoms, so the lack of depression prediction may reflect low symptom burden. The Finnish Beck Anxiety Inventory validity and reliability data are scarce, so the anxiety finding depends on a measure with limited psychometric support. Outcomes were self-reported postal questionnaires, and the analysis combined the 3-month and 12-month follow-up points after finding no difference in change between trial groups, so it does not describe how predictors changed over time.

The authors declared no conflicts of interest. Funding came from Kuopio University Hospital EVO and VTR grants and the North Savo Regional Fund of the Finnish Cultural Foundation.

Do not conclude that treating anxiety, depression, self-efficacy, kinesiophobia or catastrophizing will improve knee osteoarthritis pain or function. This analysis found baseline associations over one year and did not test those treatments. The original cognitive-behavioural intervention group also did not predict outcomes.