Proposal for a revised Barthel index classification based on mortality risk assessment in functional dependence for basic activities of daily living.

Introduction: Functional dependence on the performance of basic activities of daily living (ADLs) is associated with increased mortality. In this study, the Barthel index and its activities discriminate long-term mortality risk, and whether changes in this index are necessary to adapt it to detect mortality risk is examined. Methods: Longitudinal study, carried out at the Orcasitas Health Center, Madrid (Spain), on the functional dependent population (Barthel ≤ 60). It included 127 people, with a mean age of 86 years (78.7% women and 21.3% men). Functional capacity was assessed using the Barthel index, and this index and each item it contains were analyzed as a test in relation to survival at three years, using tools that evaluate precision, discrimination, and calibration. The date of death was obtained from the health system. Results: Greater dependency to perform chair-to-bed transfers was associated with an increased mortality risk (HR 2.957; CI 1.678-5.211). Also, individuals with severe (HR 0.492; CI 0.290-0.865) and moderate (HR 0.574; CI 0.355-0.927) ADL dependence had a reduced mortality risk when more independent in chair-to-bed transfers. Among people with moderate ADL dependence, this percentage was 48%. Using dependence-independence for chair-to-bed transfer as a screening test for mortality, the test showed high sensitivity (0.91) and specificity (0.83), a positive likelihood ratio of 5.45, and a negative likelihood ratio of 0.11. The area under the ROC curve was 0.814 (CI 0.658-0.970; Conclusion: ADL dependence for chair-to-bed transfers is an independent risk factor for mortality for any level of dependency. Therefore, a new classification of the Barthel index is proposed, in which "being dependent or requiring great assistance to perform chair-to-bed transfers" is considered severe dependence, even when the total score obtained via the Barthel Index is ≥40. We propose its use as a screening test in parallel to the Barthel index. The study suggests that the Barthel Index may have limitations in adequately discriminating mortality risk.