Patient Expectations as Predictors: Understanding Patient-Reported Outcomes in Musculoskeletal Conditions

Patient expectations are a key component of the shared decision-making process and have been found to be associated with treatment outcomes. However, there are concerns about the published research on patient expectations, including heterogeneity of the studies, variability, ceiling effect, and lack of validity of the measuring tools.

This prospective, longitudinal cohort study investigated whether initial patient expectations for physical therapy, measured by the Expectation for Treatment Scale (ETS), could predict PROMIS physical function (PF) and pain interference (PI) scores at six and 12 weeks in patients with musculoskeletal conditions. A secondary aim was to determine the explanatory power of patient expectations on these outcomes.

This study followed a prospective cohort design. Participants aged 18-89 years with any musculoskeletal condition, receiving outpatient physical therapy within the Bellin Health System were recruited from January 2024 to July 2024. Data collected included demographics, health information, ETS scores at baseline, and PROMIS PF and PI scores at baseline, six and 12 weeks. Statistical analysis included descriptive statistics, uni- and multivariable quantile regression, and multiple imputations to handle missing data.

The ETS was a significant predictor of both PROMIS PF (p < 0.001) and PROMIS PI (p < 0.001) at 12 weeks, but not at 6 weeks. The multivariable models showed medium explanatory power, with pseudo R² values of 0.28 for PF and 0.15 for PI at 12 weeks.

In this cohort, a patient's baseline expectations score is a positive and significant predictor of long-term (12-week) PF and PI-related outcomes in musculoskeletal conditions. Pseudo R² was higher for physical function than for pain interference, indicating higher explanatory power of the model for 12-week PF. These findings suggest clinicians can use patient expectations to help better predict and potentially improve patient outcomes.