Chart-Derived Frailty Index and 90-Day Mortality After Burn Surgery

Abstract

Introduction: Frailty is a reduced physiological reserve condition associated with postoperative morbidity and mortality. The chart-derived frailty index (CFI) can measure frailty using demographic and laboratory values. We evaluated the association of preoperative CFI with 90-d mortality after burn surgery.

Methods: This large retrospective study included burn intensive care unit (ICU) patients between 2012 and 2021 and calculated CFI using the sum of the following five variables: age >70 y, body mass index <18.5 kg/m², hematocrit <35%, albumin <3.4 g/dL, and creatinine >2.0 mg/dL; high CFI was a score of 3-5. Postoperative 90-d mortality rate, major adverse cardiac events (MACE), pneumonia, continuous renal replacement therapy (CRRT) requirement, and prolonged ICU stay (>60 d) were evaluated.

Results: Of 1118 patients, 147 (13.1%) had high CFI. High CFI patients had a higher 90-d mortality rate than did low CFI patients (38.8% versus 22.6%, P < 0.001). A high CFI was significantly associated with postoperative 90-d mortality (hazard ratio = 4.124, 95% confidence interval = 2.980-5.707, P < 0.001) in multivariate Cox regression analysis. Kaplan-Meier analysis revealed significantly different postoperative 90-d mortality rates between patients with high and low CFIs (log-rank test, P < 0.001). Incidences of postoperative MACE, pneumonia, the need for CRRT, and prolonged ICU stay were significantly higher in patients with high CFIs than in those with low CFIs.

Conclusions: Preoperative high CFI was associated with increased 90-d mortality, MACE, pneumonia, CRRT requirement, and ICU stay following burn surgery.

Keywords: Burn; Chart-derived frailty index; Mortality.