Can a Barthel score be derived from the FIM?

Objective: To establish whether a Barthel score derived by translation from the motor items of the Functional Independence Measure (FIM) would equate to the directly scored measure.

Design: Conversion criteria for motor item scores on the FIM scale to Barthel scores were first developed. To test these criteria, 40 consecutive patients were assessed for Barthel and FIM scores by the multidisciplinary team who were unaware of the conversion criteria. The derived Barthel score was compared with the directly scored Barthel Index.

Results: A very high degree of correlation was observed between total scores of the direct and derived Barthel (Spearman's rho = 0.99), which is highly significant, and no significant differences were seen between scores for any of the individual items (Wilcoxon signed rank test). Item by item analysis across the study population was undertaken to confirm the conversion criteria. Absolute agreement between the two methods ranged from 75 to 100% and kappa values from 0.53 to 1.0.

Conclusions: This study demonstrates that a Barthel Index can be derived from the motor items of the FIM and there is a good agreement with the directly assessed Barthel score. Although a larger study may help to delineate the exact conversion criteria for one item, the current system provides an accurate and usable translation of the total score and serves as a major step towards achieving a common language in outcome measurement for rehabilitation.