Evaluation of Hospital Readmission and Mortality Risk in Older Frail Patients Using the FIB-4 Index: A Cohort Study.

Background

Recurrent hospitalizations and mortality are frequent among frail older adults, reflecting reduced physiological reserve and vulnerability to stressors. Identifying inexpensive and readily available biomarkers for risk stratification remains a priority in geriatric medicine. The Fibrosis-4 (FIB-4) index, originally developed to estimate liver fibrosis, has recently emerged as a systemic risk marker beyond hepatic disease.

Methods

We conducted a prospective observational study including 248 hospitalized patients aged ≥ 70 years admitted to an internal medicine department. Frailty was assessed using the Frailty Index (FI), which was calculated at hospital admission. The primary composite endpoint was all-cause mortality or unplanned hospital readmission during follow-up (mean 159 ± 128 days).

Results

Participants were categorized as low FIB-4 (< 1.3, n = 53) or intermediate-high FIB-4 (≥ 1.3, n = 195). Individuals with FIB-4 ≥ 1.3 showed higher inflammatory burden (increased C-reactive protein), lower nutritional reserve (reduced pre-albumin), higher D-dimer levels, and longer hospital stay. During follow-up, 128 events occurred (39 deaths and 89 readmissions). FIB-4 ≥ 1.3 was associated with increased risk of the composite endpoint (HR 2.268, 95% CI 1.210-4.252, p = 0.011). After adjustment for sex, smoking status, BMI, and frailty index, FIB-4 remained independently associated with adverse outcomes (HR 2.045, 95% CI 1.206-4.199, p = 0.016).

Conclusions

FIB-4 appears to reflect reduced biological reserve and systemic vulnerability rather than isolated liver dysfunction. As a cost-free parameter derived from routine blood tests, FIB-4 may represent a practical tool for risk stratification in hospitalized frail older adults.