Frailty Index Based on Common Laboratory Tests for Patients Starting Home-Based Medical Care

To determine whether a Frailty Index based on laboratory tests (FI-lab) is associated with clinical outcomes independently of a standard nonlaboratory Frailty Index (FI-clinical) in older patients starting home-based medical care.

Secondary analysis of data from a multicenter prospective cohort study.

Patients aged ≥65 years who were starting home-based medical care services provided by doctors and nurses at Nagoya, Japan.

We calculated FI-lab (proportion of abnormal results out of 25 commonly tested laboratory parameters) and FI-clinical using 42 items based on data obtained at enrollment. The primary outcome was mortality within 2 years after starting home-based medical care. A sensitivity analysis was also conducted with 1-year mortality as the outcome. Other outcomes included hospitalization and nursing home admission within 2 years.

In total, 188 patients (mean age 79.9 ± 10.2 years, 57.5% male) were included. The median FI-lab was 0.40 [interquartile range (IQR) 0.29-0.50] and the median FI-clinical was 0.32 (IQR 0.24-0.43). Sixty-nine patients (36.7%) died within 2 years of starting home-based medical care. A Cox proportional hazards regression analysis including age, sex, FI-lab, and FI-clinical as independent variables revealed that FI-lab was associated with 2-year mortality independently of FI-clinical [FI-lab per 0.1 unit, odds ratio (OR) 1.49, 95% CI 1.25-1.77; FI-clinical per 0.1 unit, OR 1.13, 95% CI 0.90-1.41]. The sensitivity analysis showed similar results for 1-year mortality. Neither FI-lab nor FI-clinical was associated with hospitalization or nursing home admission within 2 years.

FI-lab was associated with 2-year mortality in patients starting home-based medical care, independently of FI-clinical, and may be useful for risk assessment in this population. Studies with larger sample sizes are needed.