Importance
The Frailty Index (FI) is a known predictor of adverse outcomes in geriatric patients. The usefulness of the FI as an outcome measure in geriatric trauma patients is unknown.
Objective
To assess the usefulness of the FI as an effective assessment tool in predicting adverse outcomes in geriatric trauma patients.
Design, Setting, and Participants
A 2-year (June 2011 to February 2013) prospective cohort study at a level I trauma center at the University of Arizona. We prospectively measured frailty in all geriatric trauma patients. Geriatric patients were defined as those 65 years or older. The FI was calculated using 50 preadmission frailty variables. Frailty in patients was defined by an FI of 0.25 or higher.
Main Outcomes and Measures
The primary outcome measure was in-hospital complications. The secondary outcome measure was adverse discharge disposition. In-hospital complications were defined as cardiac, pulmonary, infectious, hematologic, renal, and reoperation. Adverse discharge disposition was defined as discharge to a skilled nursing facility or in-hospital mortality. Multivariate logistic regression was used to assess the relationship between the FI and outcomes.
Results
In total, 250 patients were enrolled, with a mean (SD) age of 77.9 (8.1) years, median Injury Severity Score of 15 (range, 9-18), median Glasgow Coma Scale score of 15 (range, 12-15), and mean (SD) FI of 0.21 (0.10). Forty-four percent (n = 110) of patients had frailty. Patients with frailty were more likely to have in-hospital complications (odds ratio, 2.5; 95% CI, 1.5-6.0; P = .001) and adverse discharge disposition (odds ratio, 1.6; 95% CI, 1.1-2.4; P = .001). The mortality rate was 2.0% (n = 5), and all patients who died had frailty.
Conclusions and Relevance
The FI is an independent predictor of in-hospital complications and adverse discharge disposition in geriatric trauma patients. This index should be used as a clinical tool for risk stratification in this patient group.
The geriatric population is the fastest-growing segment in the US population, accounting for more than 20% of all hospital admissions.1,2 Geriatric patients are living longer and leading active lifestyles, resulting in an increase in the burden of this patient group across trauma centers.3,4 The management of these patients is challenging, with wide disparities in outcomes across centers.4,5
Studies4-7 have shown that early assessment and identification of vulnerable patients is an important determinant of outcomes in trauma patients. Mechanism of injury, Injury Severity Score, vital signs on presentation, comorbidities, and medication history are known to be associated with the development of in-hospital complications, longer hospital length of stay, and adverse discharge disposition in trauma patients.3,8-12 Several scoring systems have been developed to predict outcomes in this patient group.8-12 However, the usefulness of these commonly used assessment tools is limited because they fail to assess the altered physiological capacity among geriatric trauma patients.
Frailty is defined as a syndrome of decreased physiological reserve and resistance to stressors, which results in increased vulnerability to poor health outcomes, worsening mobility and disability, hospitalizations, and death.3,13,14 It has been shown to predict in-hospital complications, discharge to institutional care, and mortality among geriatric surgical patients.15-22 However, the role of frailty in trauma patients remains unclear. The current guidelines defining the management of geriatric trauma patients fail to take into account the low physiological reserve and the altered response to injury in these patients.6,23 In addition, these guidelines highlight the lack of an effective assessment tool for evaluating outcomes in geriatric trauma patients. The aim of our study was to assess the usefulness of the Frailty Index (FI) as an assessment tool in predicting outcomes in geriatric trauma patients. We hypothesized that the FI is an effective tool to predict adverse outcomes in this patient group.
After approval from the institutional review board at the University of Arizona College of Medicine, we performed a 2-year (June 2011 to February 2013) prospective cohort study of all geriatric trauma patients seen at our level I trauma center. Written informed consent was obtained from all patients. Geriatric patients were defined as those 65 years or older. Geriatric trauma patients with in-hospital admission were included in the study. Patients transferred from other institutions, from a rehabilitation center, or from a skilled nursing facility were excluded from the study, as were patients who did not consent to enrollment and patients who were intubated or nonresponsive without family members, in whom the FI could not be calculated. The Figure shows the algorithm for patient inclusion in our study.
For each patient, we prospectively recorded the following data: patient demographics (age, sex, and race/ethnicity), injury characteristics (type and mechanism of injury), and vital signs on presentation (Glasgow Coma Scale score, systolic blood pressure, heart rate, and body temperature), as well as the need for operative intervention, in-hospital complications, hospital and intensive care unit lengths of stay, and discharge disposition. We obtained the Injury Severity Score and the head Abbreviated Injury Scale score from the trauma registry.
The study protocol was 5-fold. First, geriatric patients were approached by a single investigator (B.J., V.P, or B.Z.) on the first day of their hospital admission for enrollment in the study. Second, after providing informed consent, patients received an explanation of the variables comprising the Frailty Index Questionnaire, including clarification that the questionnaire assesses the patient’s preinjury condition. Third, each patient responded to the Frailty Index Questionnaire, and the FI was calculated based on the responses; in the case of intubated or nonresponsive patients, information on any preexisting neurologic condition and on the severity of injury was obtained from the patient’s closest relative, or the patient was excluded from the study if family members were unavailable. Fourth, each patient was followed up during the hospital course, and data were collected. Fifth, no clinical decisions were made based on the patient’s FI.
For our study, we used the 50-variable FI by Searle et al,13 which was obtained from the Canadian Study of Health and Aging. The variables gathered were patient demographics (age, comorbidities, and medication history), social activity, activities of daily living, nutritional status, and general mood. The eAppendix in the Supplement contains details on the 50-variable FI used in our study. The presence of a deficit in the patient was scored as 1 point. Most variables in the FI were dichotomized (ie, 1 point when a deficit was present and 0 points when no deficit was present), while other variables had multiple categories (eg, for a history of falls, “most of the time” was scored as 1 point, “sometimes” was scored 0.5 point, and “never” was scored as 0 points). The FI was calculated as the total number of deficits present in the patient divided by the total number of variables (n = 50) in the Frailty Index Questionnaire. The FI ranged from 0 (representing nonfrail status) to 1 (representing severely frail status). Patients were then stratified into 2 groups as frail or nonfrail based on their FI. We chose the established optimal cutoff of 0.25 for dichotomizing patients into frail and nonfrail categories.13 An FI of 0.25 is the standardized cutoff to define frailty in patients according to the FI by Searle et al.13
The primary outcome measure was the development of in-hospital complications. The secondary outcome measure was adverse discharge disposition. We defined in-hospital complications as cardiac (myocardial infarction and cardiopulmonary arrest), pulmonary (pneumonia and pulmonary embolism), infectious (sepsis and urinary tract infections), hematologic (deep venous thrombosis and disseminated intravascular coagulation), renal (renal insufficiency), and reoperation. We defined adverse discharge disposition as discharge to a skilled nursing facility or in-hospital mortality.
Data are reported as means (SDs) for continuous descriptive variables, as medians (ranges) for ordinal descriptive variables, and as proportions for categorical variables. To analyze data, we used t test for parametric variables and Mann-Whitney test for nonparametric variables. χ2 Test was used to assess differences in proportions for categorical variables. Spearman rank correlation analysis was performed to assess the correlation between age and the FI. Univariate analysis was performed to assess the association between factors and outcome measures. Variables with a significant (P ≤ .20) association on univariate analysis were then used in a multivariate logistic regression model to identify independent factors associated with outcomes. On multivariate logistic regression analysis, variables were considered significant at P ≤ .05. For all statistical analyses, we used commercially available software (STATA Data Analysis and Statistical Software version 11.0; StataCorp LP).
In total, 250 consecutive geriatric trauma patients were prospectively enrolled, 44.0% (n = 110) of whom had frailty. The Figure shows the algorithm for patient inclusion in the study. The mean age was 77.9 (8.1) years, 69.2% (n = 173) were male, the median Injury Severity Score was 15 (9-18), the median head Abbreviated Injury Scale score was 2 (2-3), the median Glasgow Coma Scale score was 15 (12-15), and the mean FI was 0.21 (0.10). No differences between patients with vs without frailty were observed in age (P = .21), mechanism of injury (P = .09), systolic blood pressure (P = .30), or Glasgow Coma Scale score (P = .91) on presentation. Patients with frailty were more likely to have a higher Injury Severity Score (P = .04) and a higher mean FI (P = .01) than patients without frailty. No significant correlation was found between the FI and age (R2 = 0.47, P = .18). Table 1 lists the demographics of our study population.
Complications and Discharge Disposition
In total, 28.4% (n = 71) of patients developed in-hospital complications. Patients with frailty were more likely to develop in-hospital complications than patients without frailty (37.3% vs 21.4%, P = .001). Urinary tract infections (n = 12), followed by pneumonia (n = 10), were the most common complications among patients with frailty.
Overall, 7.2% (n = 18) of patients underwent operative intervention, 38.9% (n = 7) of whom underwent reoperation. No difference was observed in the rates of reoperation between patients with vs without frailty (P = .54). Table 2 lists the in-hospital complications in patients with and without frailty.
Table 3 lists the outcomes of the study population. Patients with frailty had longer hospital length of stay (P = .01) and intensive care unit length of stay (P = .01) than patients without frailty. In total, 23.6% (n = 59) had adverse discharge disposition (54 to a skilled nursing facility and 5 in-hospital deaths). Patients with frailty were more likely to have adverse discharge disposition than patients without frailty (37.3% vs 12.9%, P = .001). The overall mortality rate was 2.0% (n = 5). All patients who died in-hospital had frailty.
Factors Associated With In-Hospital Complications
On univariate analysis, an FI of 0.25 or higher was associated with the development of in-hospital complications (P = .01). Age (P = .02), systolic blood pressure (P = .04), heart rate (P = .11), and Injury Severity Score (P = .01) were also associated with the development of in-hospital complications. After adjusting for age, systolic blood pressure, heart rate, and Injury Severity Score in a multivariate regression model, an FI of 0.25 or higher was an independent predictor of the development of in-hospital complications (P = .001). Table 4 summarizes the results of the univariate and multivariate regression analyses for factors associated with in-hospital complications.
After stratifying patients into 3 groups based on age (65-74 years, 75-84 years, and ≥85 years), an FI of 0.25 or higher remained an independent predictor of the development of in-hospital complications in each group. Table 5 summarizes the results of the multivariate regression analysis after stratifying the study population by age.
Factors Associated With Adverse Discharge Disposition
Univariate analysis identified factors associated with adverse discharge disposition. These included an FI of 0.25 or higher (P = .001), age (P = .03), male sex (P = .04), insurance status (P = .09), Glasgow Coma Scale score on presentation (P = .04), mechanism of injury (P = .09), Injury Severity Score (P = .02), and head Abbreviated Injury Scale score (P = .04).
After adjusting for age, male sex, Injury Severity Score, and mechanism of injury in a multivariate regression analysis, an FI of 0.25 or higher was an independent predictor of adverse discharge disposition (P = .001). Table 6 summarizes the results of the univariate and multivariate regression analyses for factors associated with adverse discharge disposition.
Table 7 summarizes the results of the multivariate regression analysis after stratifying the study population by age. After stratifying patients into 3 groups based on age (65-74 years, 75-84 years, and ≥85 years), an FI of 0.25 or higher remained an independent predictor of adverse discharge disposition.
Early assessment and identification of vulnerable patients is critical in optimizing outcomes in geriatric trauma patients.4-7 This study demonstrates that the FI is an effective tool to predict outcomes in this patient group. Trauma patients with frailty are more likely to develop in-hospital complications and have adverse discharge disposition than patients without frailty. The FI is superior to age and other routinely used assessment tools for determining outcomes among geriatric trauma patients. The FI should be used as a clinical tool for risk stratification across trauma centers to standardize geriatric trauma patient management.
Geriatric patients represent a growing trauma cohort without well-defined guidelines for their management. The American College of Surgeons Trauma Quality Improvement Program geriatric trauma management guidelines highlight the paucity of data defining criteria to predict outcomes in injured elderly patients.23 Similarly, the practice management guidelines from the Eastern Association for the Surgery of Trauma demonstrate a lack of robust assessment tools for predicting outcomes in geriatric patients.6 Given the higher incidence of in-hospital complications, discharge to institutional care, and mortality among geriatric trauma patients, it is imperative to develop assessment tools to tailor the management of these patients. In our study, we demonstrated the usefulness of the FI as an assessment tool for managing this patient group. We believe that the FI can be an effective tool for assessing vulnerable geriatric trauma patients and for streamlining their management to improve outcomes.
The development of in-hospital complications is associated with decreased quality of life and increased health care costs. Studies15-17,19,22,24 have highlighted the role of frailty in predicting complications in geriatric patients. In our study, we used a modification of the FI by Searle et al13 (50 variables) and found that trauma patients with frailty were 2.5 times more likely to develop in-hospital complications than trauma patients without frailty. Makary et al15 demonstrated that frailty independently predicted postoperative complications in surgical patients. Similarly, Saxton and Velanovich24 highlighted the role of frailty as an effective tool to identify elderly patients at higher risk of developing complications. However, both of these studies were retrospective and included a heterogeneous patient population undergoing elective general surgical procedures. We demonstrated that the FI can be implemented in the acute setting of trauma and should be used to identify patients at higher risk for the development of complications after injury.
In our study, urinary tract infections, followed by pneumonia, were the most common complications seen among patients with frailty. In a series of patients undergoing colorectal surgery, Kristjansson et al25 found that those with frailty were more likely to develop pulmonary complications than those without frailty. Similarly, Dasgupta et al26 found that patients with a high frailty score were 6 times more likely to develop pulmonary complications than patients without frailty. We believe that the higher incidence of pulmonary complications among patients with frailty is attributable to their low lung capacity due to the altered physiological capacity in these patients.
Discharge disposition is a critical component in the management of trauma patients. Studies8-12 have shown that age and Injury Severity Score are significant predictors of adverse discharge disposition among trauma patients. In our study, we found that the FI is superior to age and Injury Severity Score in predicting discharge disposition in trauma patients. After stratifying patients based on age, the FI remained an independent predictor of adverse discharge disposition. Robinson et al16 found that patients with frailty were likely to require institutional care after a major elective procedure. Similarly, Lee et al27 demonstrated that patients with frailty were more likely to have adverse discharge disposition after cardiac surgery. In a study by Makary et al,15 frailty was an independent predictor of adverse discharge disposition. However, all these studies were retrospective, with small sample sizes. Furthermore, variability existed in the FI assessment tool used in these studies. Our study highlights that the FI can be implemented in the acute setting of trauma, with similar results for surgical and nontrauma patients.
In our study, patients with frailty were more likely to have longer hospital and intensive care unit lengths of stay and to incur higher hospital costs. Other studies16,17,22,24,28 have shown similar results and have demonstrated that frailty status is associated with longer hospital length of stay and with higher hospital costs. We believe that early understanding of the possible outcomes in geriatric trauma patients will facilitate communication with family members and better allocate hospital resources.
Although the Injury Severity Score was higher in our study patients with frailty, the severity of injury was not associated with outcomes. We believe that the low physiological reserve and altered response to injury among patients with frailty might have contributed to their having a higher Injury Severity Score. Further understanding of frailty based on physiological and biochemical mechanisms may help us better comprehend the differences in the severity and patterns of injury among patients with vs without frailty.
Frailty is considered a state of low physiological capacity, commonly occurring in geriatric patients. In our study, we found no association between age and the FI. These findings validate the concept of frailty that assesses the true physiological capacity among individuals, which is independent of their chronologic age. We believe that expanding the scope of frailty to younger patients might be helpful in identifying the prevalence of frailty syndrome at an earlier stage and in developing focused targeted interventions.
Wide variability exists in the tools used to assess frailty in geriatric patients. Studies assessing frailty in surgical patients have used the frailty criteria developed by Makary et al15 and by Kristjansson et al25 (weight loss, exhaustion, weakness, walking speed, and physical activity) and the FI by Searle et al13 (70 variables) to assess outcomes in patients.3,16,17,20 However, an ideal tool for the clinical assessment of frailty remains controversial. In our study, we used a modification of the FI by Searle et al13 with 50 variables to assess outcomes in trauma patients, which we believe is a more comprehensive tool that is more feasible to implement in the trauma setting than the frailty score by Makary et al15 and by Kristjansson et al.25 In addition, the development of a trauma FI with fewer variables is required for assessing frailty in the emergency department.
Our study has some limitations. First, we did not evaluate the effect of frailty on long-term functional outcomes and on quality of life. Second, our results were obtained at a single academic medical center and may not be generalizable beyond similar patients. Despite these limitations, our study demonstrates the usefulness of the FI as an effective tool to predict adverse outcomes in geriatric trauma patients.
The FI is an independent predictor of in-hospital complications and adverse discharge disposition among geriatric trauma patients. Using age as the sole reference for clinical decision making is inadequate and misleading in geriatric patients. The FI should be used as a clinical tool for risk stratification among geriatric trauma patients.
Accepted for Publication: December 27, 2013.
Corresponding Author: Bellal Joseph, MD, Division of Trauma, Critical Care, Burns, and Acute Care Surgery, Department of Surgery, University of Arizona Medical Center, 1501 N Campbell Ave, Room 5411, PO Box 245063, Tucson, AZ 85724 (bjoseph@surgery.arizona.edu).
Published Online: June 11, 2014. doi:10.1001/jamasurg.2014.296.
Author Contributions: Dr Joseph had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Joseph, Pandit, Zangbar, Green, O’Keeffe, Vercruysse, Friese, Rhee.
Acquisition, analysis, or interpretation of data: Joseph, Pandit, Zangbar, Kulvatunyou, Hashmi, Green, Tang, Vercruysse, Fain, Friese, Rhee.
Drafting of the manuscript: Joseph, Pandit, Zangbar, Hashmi, Vercruysse, Rhee.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Joseph, Pandit, Zangbar, Hashmi, Tang, Friese, Rhee.
Administrative, technical, or material support: Green, O’Keeffe, Vercruysse.
Study supervision: Joseph, O’Keeffe, Vercruysse, Fain, Friese, Rhee.
Conflict of Interest Disclosures: None reported.
Previous Presentation: This study was presented at the American College of Surgeons 2013 Annual Clinical Congress; October 9, 2013; Washington, DC; and received the Excellence in Research Award, Geriatric Surgery.
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