Modified Frailty Index 5 (mFI-5) Score as a Predictive Tool for Post-traumatic Empyema in Geriatric Trauma Patients

Author(s):
Ricardo Fonseca; Melissa Canas; Leonardo Diaz; Alejandro De Filippis; Hussain Afzal; Mark Hoofnagle; Jennifer Leonard; Kelly Bochicchio; Grant Bochicchio

Background:

As life expectancy continues to increase, the incidence of geriatric trauma has risen proportionately. Traumatic chest injuries are among the most frequent injuries incurred in this population. Empyema, despite its low incidence, remains a serious post-traumatic infectious complication in this population. While few studies have described an association between chest tube placement and increased risk for post-traumatic empyema in the geriatric population, we suspect that additional risk factors such as immunosenescence related to frailty may have a more important role than age alone. The modified 5-item frailty index (mFI-5) is a risk-stratification tool that has been shown to predict adverse outcomes in geriatric populations.

Hypothesis:

We hypothesized that a higher mFI-5 score would be associated with an elevated risk for post-traumatic empyema in the geriatric population.

Methods:

We queried our prospective Trauma Registry from 2010-2018 for patients with thoracic trauma. Patients younger than 55 years old were excluded and the cohort was stratified based on the diagnosis of empyema during the hospital stay. Empyema was confirmed by imaging evidence, clinical evaluation, and/or microbiology. Demographics, thoracic procedures, and outcomes were collected. The mFI-5 scores were calculated based on the presence of congestive heart failure, diabetes mellitus, chronic obstructive pulmonary disease, and dependent functional status.

Results:

A total of 626 geriatric trauma patients with a mean age of 68 years old were included. The overall empyema rate was 4.6% (n=29). Empyema patients had a significantly higher mFI-5 Score [2.1±2 vs 1.1±1.6; p<0.001], AIS chest score [3.7±0.9 vs 3.2±0.9; p 0.003], and a higher incidence of chest tube insertion [75.9% vs 40.7%; p<0.001]. Empyema patients also had a significantly longer Hospital Length of Stay (LOS), ICU LOS, and ventilator days [28.2±7.8 vs 27.7±6.5; 19.5±15.3 vs 7.6±11.1; 12.9±20.4 vs 7.1±7.7; p<0.001]. When controlling for age, mFI-5 score, rib fracture, mechanism of injury, ventilator days, AIS chest score, and chest tube insertion; a multivariate logistic analysis demonstrated that mFI-5 was the only independent risk factor for empyema [OR 16.44, 95% CI (1.38-195); p 0.027]. In a similar logistic regression model, we categorized the mFI-5 score by >2 and found a 3-fold increase in risk for empyema [OR 3.1, 95% CI (1.06-8.82); p 0.039].

Conclusions:

An mFI-5 score >2 was associated with a 3-fold increase in post-traumatic empyema in geriatric patients with thoracic trauma. We recommend using the mFI-5 score as a simple tool to predict adverse outcomes in this high-risk study population.