Functional gain and length of stay for major rehabilitation impairment categories. Patterns revealed by function related groups.

Abstract

This study evaluates the relationship of functional severity to patterns of functional gain and length of stay (LOS) for patients discharged from medical rehabilitation. It further compares differences in patterns between summed and Rasch transformed subscales of the Functional Independence Measure (FIM). Two different schemes of the FIM-Function Related Groups (FIM-FRGs) are used to define groups of patients who present with similar degrees of functional severity. The first scheme was developed using summed admission motor and cognitive FIM subscores (FIM-FRGs). The second scheme was developed by transforming these same motor and cognitive FIM subscores into logits (Logit FIM-FRGs), thus making FIM scores more equal-interval. The study included 32,494 patients who were discharged from 123 facilities that submitted data to the Uniform Data System for Medical Rehabilitation (UDSMR) and involved the separate evaluation of 18 different rehabilitation impairment categories. Motor FIM gain was calculated for each FRG in both schemes as the patient's discharge motor FIM score minus the admission motor FIM score. There were four patterns of motor FIM gain and two patterns of LOS across rehabilitation impairment. The most common pattern in both schemes was linear trend, for which median gains and LOS were highest for patients in the most disabled FRGs and lowest for patients in the least disabled FRGs. Gain patterns differed across impairment and across the two schemes. The motor FIM gain distributions provide clinicians with a range of typical functional outcomes for patients admitted to medical rehabilitation. This descriptive approach provides clinicians and administrators with a simple way to compare the motor FIM gain and LOS patterns of patients teated in local facilities with broad-based norms. This sample includes about one-quarter of rehabilitation facilities nationwide, thus representing population standards for facilities participating in the UDSMR. Suggestions are made on how to use these norms most appropriately for both facility and patient comparison.