Ability of 3 Frailty Measures to Predict Short-Term Outcomes in Older Patients Admitted for Post-Acute Inpatient Rehabilitation

Abstract

Objectives

To evaluate the ability of 3 commonly used frailty measures to predict short-term clinical outcomes in older patients admitted for post-acute inpatient rehabilitation.

Design

Observational cohort study.

Setting and Participants

Consecutive patients (n = 207) admitted to a geriatric inpatient rehabilitation facility.

Methods

Frailty on admission was assessed using a frailty index, the physical frailty phenotype, and the Clinical Frailty Scale (CFS). Predictive capacity of the frailty instruments was analyzed for (1) nonhome discharge, (2) readmission to acute care, (3) functional decline, and (4) prolonged length of stay, using multivariate logistic regression models and receiver operating characteristic (ROC) curves.

Results

The number of patients classified as frail was 91 (44.0%) with the frailty index, 134 (64.7%) using the frailty phenotype, and 151 (73.0%) with the CFS. The 3 frailty measures revealed acceptable discriminatory accuracy for nonhome discharge (area under the curve ≥ 0.7) but differed in their predictive ability: the adjusted odds ratio (OR) for nonhome discharge was highest for the CFS [6.2, 95% confidence interval (CI) 1.8-21.1], compared to the frailty index (4.1, 95% CI 2.0-8.4) and the frailty phenotype (OR 2.9, 95% CI 1.2-6.6). For the other outcomes, discriminatory accuracy based on ROC tended to be lower and predictive ability varied according to frailty measure. Readmission to acute care from inpatient rehabilitation was predicted by all instruments, most pronounced by the frailty phenotype (OR 5.4, 95% CI 1.6-18.8) and the frailty index (OR 2.5, 95% CI 1.1-5.6), and less so by the CFS (OR 1.4, 95% CI 0.5-3.8).

Conclusions and Implications

Frailty measures may contribute to improved prediction of outcomes in geriatric inpatient rehabilitation. The choice of the instrument may depend on the individual outcome of interest and the corresponding discriminatory ability of the frailty measure.