Reliability, Validity, Clinical Utility, and Responsiveness of Measures for Assessing Mobility and Physical Function in Patients With Traumatic Injury in the Acute Care Hospital Setting: A Prospective Study

Abstract

Abstract Objective The longer-term impact of injury is increasingly recognized, but the early phases of recovery are less well understood. The best tools to measure early recovery of mobility and physical function following traumatic injury are unclear. The purpose of this study was to assess the clinical utility, validity, reliability, and responsiveness of 4 mobility and physical function measures in patients following traumatic injury. Methods In this cohort, measurement-focused study (n = 100), the modified Iowa Level of Assistance Score, Acute Care Index of Function, Activity Measure for Post-Acute Care “6 Clicks” short forms, and Functional Independence Measure were completed during first and last physical therapy sessions. Clinical utility and floor and ceiling effects were documented. Known-groups validity (early vs late in admission and by discharge destination), predictive validity (using 6-month postinjury outcomes data), and responsiveness were established. Interrater reliability was assessed in 30 patients with stable mobility and function. Results Participants had a median age of 52 years (interquartile range = 33–68 years), and 68% were male. The modified Iowa Level of Assistance Score, Acute Care Index of Function, and “6 Clicks” short forms were quick to administer (an extra median time of 30 seconds–1 minute), but the Functional Independence Measure took much longer (extra median time of 5 minutes). At the last physical therapy session, ceiling effects were present for all measures except the Functional Independence Measure (18%–33% of participants). All had strong known-groups validity (early vs late in admission and by discharge destination). All were responsive (effect sizes >1.0) and had excellent interrater reliability (intraclass correlation coefficients = 0.79–0.94). Conclusion All 4 measures were reliable, valid, and responsive; however, their clinical utility varied, and ceiling effects were common at physical therapy discharge. Impact This study is an important step toward evidence-based measurement in acute trauma physical therapy care. It provides critical information to guide assessment of mobility and physical function in acute trauma physical therapy, which may facilitate benchmarking across different hospitals and trauma centers and further progress the science and practice of physical therapy following traumatic injury.