FIM motor scores for classifying community discharge after inpatient rehabilitation for hip fracture

Objective: To assess the utility of functional status in classifying patients by discharge setting after inpatient rehabilitation for hip fracture. Design: Retrospective cohort study. Setting: A total of 1257 inpatient rehabilitation facilities in the United States. Patients: Medicare beneficiaries (N= 117,168) receiving inpatient rehabilitation for hip fracture from 2007 to 2009. Methods: Receiver operating characteristic curve analyses to assess the overall discriminatory ability of functional status scores (Functional Independence Measure [FIM] total, FIM cognition, and FIM motor) and to identify the functioning threshold that best differentiates patients by discharge setting. Main Outcome Measurements: Discharge setting (community versus institutional). Results: Approximately 68% of patients were discharged to the community after inpatient rehabilitation for hip fracture. Receiver operating characteristic curve analyses indicate that discharge FIM motor ratings (area under the curve: 0.84) alone are as effective as a multivariable model (area under the curve: 0.85), including sociodemographic and clinical factors, in discriminating patients discharged to the community from those discharged to an institution. A discharge FIM motor rating of 58 yielded the best balance in sensitivity and specificity for classifying patients by discharge setting. Conclusions: Discharge FIM motor ratings demonstrated good discriminatory ability for classifying discharge setting. An FIM motor rating of 58 may serve as a clinical tool to guide treatment plans and/or as additional information in complex discharge planning decisions for patients with hip fracture.