Converting Functional Autonomy Measurement System Scores of Patients Post-Stroke to FIM Scores

The Functional Independence Measure (FIM) is widely used to assess persons post-stroke. The Quebec government has selected the Functional Autonomy Measurement System (SMAF) for use in all care settings. In this article, we propose simple equations to convert SMAF scores to FIM scores for persons undergoing post-stroke rehabilitation. Persons post-stroke (n=143) from three rehabilitation centres were assessed at admission and discharge using the FIM and SMAF. The sample was randomly split into derivation and validation data sets. Regression analysis was performed on the first data set to derive a conversion equation at each time point. The validity of the equations was measured using correlation coefficients, and differences between the observed and predicted FIM scores were computed from the second data set. The relationship between the SMAF and FIM scores was linear at admission but quadratic at discharge. The proposed equations are, at admission, FIM=139-1.5×SMAF and, at discharge, FIM=118-0.018×SMAF². The observed and predicted FIM scores were highly correlated in the validation data set (rs=0.92 and 0.93 at admission and discharge, respectively). Furthermore, the equations performed well in classifying stroke severity compared with a classification based on the observed FIM scores. SMAF scores can be reliably converted to FIM scores using the proposed equations, thus facilitating international trials in stroke rehabilitation.