Comparison of the modified Frailty-Index based on laboratory tests and the Clinical Frailty Scale in predicting mortality among geriatric rehabilitation inpatients: RESORT

Abstract

ObjectiveTo compare the associations of the FI-lab, modified (m)FI-lab and Clinical Frailty Scale (CFS) with one-year mortality. Study designAn observational longitudinal inception cohort of inpatients admitted to the geriatric rehabilitation wards in the Royal Melbourne Hospital, Victoria, Australia. Main outcome measuresThe measured ratio was defined as the proportion of measured laboratory tests to the total number of tests (n = 77). The FI-lab is the proportion of abnormal results to the total measured laboratory tests. The mFI-lab was calculated by dividing the FI-lab by the measured ratio. The measured ratio of laboratory tests, FI-lab, mFI-lab and CFS were assessed at admission to geriatric rehabilitation. Patients’ mortality data were obtained from the Registry of Births, Deaths and Marriages Victoria and medical records. ResultsThe total of 1819 inpatients had a median age of 83.3 [77.5–88.3] years and 56.5% were female. The median measured ratio, FI-lab, mFI-lab and CFS scores were 0.58 [0.47–0.70], 0.31 [0.23–0.38], 0.51 [0.38–0.69] and 6 (Abbasi et al., 2018Gill, Gahbauer, Allore & Han, 2006; Howlett et al., 2014;) respectively. The one-year mortality rate was 17.1%. The measured ratio was not associated with one-year mortality. Higher FI-lab (hazard ratio (HR)=1.180, 95%CI: 1.037–1.343), mFI-lab (HR=1.074, 95%CI: 1.030–1.119) and CFS scores (HR=1.350, 95%CI: 1.191–1.530) were associated with higher risk of one-year mortality. The area under the curve (AUC) of FI-lab, mFI-lab and CFS with one-year mortality were 0.581, 0.587 and 0.612 respectively. ConclusionThe FI-lab, mFI-lab and CFS poorly predict mortality in geriatric rehabilitation inpatients despite the statistically significant associations shown.