The hospital frailty risk score in critically ill patients with sepsis is an independent risk factor for in-hospital mortality : results from MIMIC-IV database

Objective: To investigate the relationship between frailty assessed by the HFRS and in-hospital mortality in ICU patients with sepsis. Method: A retrospective analysis of septic ICU patients from the MIMIC-IV database assessed frailty using the Hospital Frailty Risk Score (HFRS). Patients were categorized into non-frail (HFRS < 5, n = 3,744), pre-frail (5 ≤HFRS < 15, n = 2,539), and frail (HFRS ≥15, n = 2,147) groups. The primary outcome was in-hospital mortality. Logistic regression, with restricted cubic splines (RCS), analyzed the relationship between HFRS ,both as a categorical and continuous variable, and mortality. Inverse probability weighting (IPW) validated the results, and subgroup analyses explored frailty-mortality correlations in different patient groups. Results: A total of 8,430 patients were included, with 3,761 (44.6%) males and a mean age of 69.39 [58.37, 79.76] years. Among them, 2,704 (32.1%) died during hospitalization. The analysis showed that in-hospital mortality increased with higher frailty levels, regardless of whether HFRS was treated as a continuous or categorical variable. RCS revealed a nonlinear relationship between HFRS and mortality. After adjusting for confounders, both pre-frail and frail statuses were significantly associated with higher in-hospital mortality risk (OR [95% CI]: pre-frail vs. non-frail: 1.33 [1.15–1.53], p < 0.001; frail vs. non-frail: 1.38 [1.18–1.62], p < 0.001). These findings were confirmed by IPW. Subgroup analyses showed significant interactions between frailty and mortality in patients receiving vasopressors, continuous renal replacement therapy (CRRT), mechanical ventilation, and those with varying heart rates, respiratory rates, and creatinine levels. Conclusion: Elevated HFRS is an independent risk factor for in-hospital mortality in septic ICU patients.