Assessing functional status after intensive care unit stay: the Barthel Index and the Katz Index.

OBJECTIVE: To assess the functional status of post-ICU patients using the Barthel Index (BI) and the Katz Index (KI) and to assess which is more suitable for this population. DESIGN: Retrospective longitudinal study. SETTING: Public tertiary hospital in São Paulo (Brazil). PARTICIPANTS: Patients aged ≥18 years old, admitted to ICU, who were treated with mechanical ventilation (MV) ≥ 24 h and were discharged to ward. EXCLUSION CRITERIA: Inability to answer the BI and the KI; limiting neurological or orthopaedic conditions; ICU stay ≥90 days. Patients transferred to or from other hospitals or who died in the wards were not analysed. INTERVENTION: BI and KI were scored pre-ICU and post-ICU and the variation was calculated. MAIN OUTCOME MEASURES: BI and KI scores were compared using analysis based on item response theory (IRT), using degree of difficulty and discriminating items as parameters. RESULTS: Median age was 52 years old, median APACHE II score was 15. Median ICU stay was 11 days and median MV duration was 4 days. BI variation was 44% and KI variation was 55%. In IRT analysis, BI considered a larger number of items with different levels of difficulty. CONCLUSION: Both the BI and the KI revealed significant deterioration of functional status after ICU discharge. The IRT analysis suggested that the Barthel Index might be a better scale than the Katz Index for the assessment of functional status of patients discharged from ICU, since it presented better discrimination of the ability to carry out the tasks.