Factors shaping expectations for complete relief from symptoms during rehabilitation for patients with spine pain.

The study was exploratory and tested all possible interactions without specific hypotheses, so findings may reflect chance. It was a secondary analysis of previously collected trial data, so the researchers could not set a sample size or power calculation before the analysis. The expectation question was a single item created for the original trials, with unknown reliability and face validity. The five response options were collapsed into a binary outcome, and patients who answered 'not sure' were excluded, which may have lost precision. Participants were people who agreed to join trials and were seeking physical therapy care, so they may have had unusually high expectations. Expectation was measured only at baseline, so the analysis cannot say how expectations changed over time. Some model estimates were unstable, especially for sex and pain onset, and few patients had very high disability, so those findings need caution. The analysis used baseline survey data, so it cannot show that any factor caused the expectation.

Do not conclude that these factors caused expectations or that changing them will improve treatment outcomes. This was an exploratory secondary analysis of baseline survey data, and the expectation question was not validated.