The Relationship Among 3 Generic Patient-Reported Outcome Instruments in Patients With Lower Extremity Health Conditions

Context: Generic patient-reported outcome (PRO) instruments are designed to capture health-related quality-of-life outcomes and to determine treatment effectiveness from the patient's perspective. Multiple generic PROs are used in clinical practice, and an investigation of the psychometric properties of these instruments in a high-functioning, physically active population is important for the future use of these instruments. Objective: To determine the relationship among 3 generic PROs: the modified Disablement in the Physically Active (mDPA) Scale, the Patient-Reported Outcome Measurement Information System Physical Function (PROMIS-PF), and the Short Form 12 (SF-12) in physically active patients seeking treatment for a lower extremity health condition. Design: Cross-sectional study. Setting: Athletic training clinical facility, physical therapy clinic. Patients or Other Participants: One hundred patients seeking rehabilitation services for a lower extremity health condition. Main Outcome Measure(s): All patients completed a demographic questionnaire and the 3 generic PROs at 1 time point during their rehabilitation: the mDPA-Total, mDPA-physical summary component (mDPA-PSC), mDPA-mental summary component (mDPA-MSC), the PROMIS-PF, and SF-12 mental component summary (SF-MCS) and physical component summary (SF-PCS). Separate Spearman rank (t) correlations were performed to assess the strength of the relationship among PRO instruments. The floor and ceiling effects were also examined. Results: A strong relationship was present between the SF-12 PCS and the mDPA-Total (r = -0.65), the mDPA-PSC (r = -0.64), and the PROMIS-PF (r = 0.65). Significant moderate relationships were identified between the mDPA-MSC and the SF-12 PCS (r=-0.43) and MCS (r=-0.53). Weak relationships were noted between the mDPA-Total and SF-12 MCS (r = -0.21) and the SF-12 MCS and mDPA-PSC (r = -0.10) and PROMIS-PF (r= 0.20). Conclusions: The PROMIS-PF and mDPA had good convergent and divergent validity. Clinicians treating physically active patients should consider these instruments for use in clinical practice. Future researchers should examine additional psychometric properties of these instruments in physically active patients.