Assessment of vulnerable older adults' physical function according to the Japanese Long-Term Care Insurance (LTCI) system and Fried's criteria for frailty syndrome

This study aimed to evaluate the physical frailty status of vulnerable older adults as classified in the Japanese LTCI system and to compare this with Fried's definition. A total of 444 older adults were classified based on the LTCI system as independent, vulnerable, or dependent, and 400 of these participants also fit Fried's criteria for not frail, pre-frail or frail. We evaluated their physical function with a 12 item physical function test. We derived a physical function score (PFS) from these 12 items and a principal component analysis was used to make comparisons. The receiver operating characteristic (ROC) curve analysis was performed to identify the sensitivity and specificity of the PFS cut-off points to distinguish the dependent category from the other categories. We found significant differences and a hierarchical order for the PFSs among the three groups of the LTCI system (the independent, 0.41 ± 0.54; the vulnerable, -0.40 ± 0.76; and the dependent, -1.49 ± 0.73) and of Fried's definition (not frail, 0.50 ± 0.51; pre frail, -0.11 ± 0.63; and frail, -1.25 ± 0.98). The optimal cut-off value (OCV) was -0.593. This study showed that the range of physical function of people considered frail category (pre-frail, vulnerable, and frail) is wide and overlapping. That is, the physical function of vulnerable older adults is worse than the pre-frail, but better than the frail. To better recognize older adults in need of greater support, the vulnerable should also receive assessment of their frailty status according to Fried's definition.