2014 Moyer Award
Frailty Score on Admission Predicts Outcomes in Elderly Burn Injury Kathleen S. Romanowski, MD, Alura Barsun, FNP-C, Tina L. Pamlieri, MD, FACS, FCCM, David G. Greenhalgh, MD, FACS, Soman Sen, MD, FACS
With longer life expectancy, the number of burn injuries in the elderly continues to increase. Prediction of outcomes for the elderly is complicated by preinjury physical fitness and comorbid illness. The authors hypothesize that admission frailty assessment would be predictive of outcomes in the elderly burn population. Our primary aim was to determine if higher frailty scores were associated with higher risk of mortality for elderly burn patients. The secondary aims were to assess if higher frailty scores were associated with increased length of stay, increased needs for mechanical ventilation and poor discharge disposition. A 2-year retrospective chart review was performed of all admitted acute burn patients 65 years or older. Data collected included: age, gender, %TBSA of burn injury, presence of inhalation injury, in hospital mortality, hospital length of stay, ventilator days, ICU length of stay, surgical procedures, insurance status, and discharge disposition. Frailty scores were assessed from admission data and calculated using the Canadian Study of Health and Aging clinical frailty scale. A total of 89 patients met entry criteria. Mean age was 75.3 ± 8.1 years and consisted of 62 men and 27 women. Mean %TBSA was 9.6 ± 9.1% and mean frailty score (FS) was 4.5 ± 1.2. Eighty patients survived to discharge and nine died. Nonsurvivors had significantly higher FS compared to survivors (5.2 ± 1.2 vs 4.4 ± 1.2). FS were also significantly higher in patients discharged to skilled nursing facilities (SNF) (5.34 ± 0.9) compared to those who were discharged home (4.1 ± 1.2) or to physical rehabilitation facilities (4 ± 1.5). Multivariate linear regression analysis revealed that age (B = 0.04) and discharge to SNF (B = 1.2) are independently associated with higher FS. However, survivors were independently associated with a significantly lower FS (B = −1.3). Multivariate logistic regression analysis revealed high admission FS independently increased the risk of discharge to SNF (odds ratio of 2.5 [1.3–4.8, 95% confidence interval]) and increased the risk of mortality (odds ratio of 1.67 [1.01–2.7, 95% confidence interval]). Frailty scores on admission allow for a more complete assessment of elderly patients and can be used to establish benchmark models for burn injury outcomes. In addition FS can be used as a research tool to improve outcomes for elderly burn injured patients. (J Burn Care Res 2015;36:1–6)
The number of elderly in the United States is now larger than it has ever been in history. The 2010 census reveals that there are 40.3 million people age 65 older. This is a 5.3% increase compared to the 2000 census.1 As the elderly population grows From the University of California Davis, Shriners Hospitals for Children, Sacramento, California. Address correspondence to Soman Sen, MD, University of California Davis, Shriners Hospitals for Children, 2425 Stockton Blvd. Suite 718, Sacramento, California 95817. Email: soman. [email protected]. Copyright © 2014 by the American Burn Association 1559-047X/2015 DOI: 10.1097/BCR.0000000000000190
so does the number of elderly burn victims. However, despite an overall improvement in outcomes from burn injuries, elderly burn victims suffer from worse outcomes. Elderly burn patients have much longer hospital admissions compared to younger adult burn patients despite similar extents of burn injury.2 More concerning is the evidence that independent of the extent of burn injury, elderly burn patients who are discharged to skilled nursing facilities (SNFs) die more often and have poor long-term physical function.3 Furthermore, significant physical and psychological impairments are present in elderly burn patients up to 1 year after discharge.4 1
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2 Romanowski et al
Traditional models to estimate burn outcomes have used age and total body surface area % (%TBSA) as their main determinants.5 As burn care has evolved new models have been developed that included a wide variety of factors including presence of full thickness burn, inhalation injury, and gender in addition to age and %TBSA.6 In the elderly there have even been attempts to examine the extent to which comorbidities affect mortality.7 Despite the many methods for predicting mortality, none of these models takes into consideration the impact of preinjury physiologic condition. A recent investigation by Masud et al8 in 2013 examined the effects of preinjury physical condition on mortality and outcomes using the Canadian Study of Health and Aging clinical frailty scale. They were able to demonstrate that high frailty scores (poor preinjury physical condition) accurately predicted mortality and poor outcomes in elderly burn patients (Table 1). While this study expanded on the idea that physiologic age was more important than chronologic age in predicting outcomes in elderly burn patients the study only included burn injuries that were larger than 10% TBSA (total burn surface area). Given this, the aim for this investigation is to determine the utility of preinjury frailty assessment in determining outcomes for all elderly burn victims. We hypothesize that a high preinjury frailty score will be predictive of a poor outcome and higher mortality after a burn injury in elderly patients.
METHODS After approval from the local institutional review board, we performed a retrospective review of all patients 65 years old and greater who were admitted to the hospital with a thermal injury from June 2011 to May 2013. Patients were identified through our local Trauma Registry modified for American College of Surgery (TRACS) database. Patients were excluded if they were determined to have suffered a nonsurvivable injury. This assessment was made at the time of admission by the admitting burn surgeon and was based on the extent of burn injury and age. Data collected included: age, gender, % TBSA of burn injury, presence of inhalation injury, in hospital mortality, hospital length of stay, ventilator days, ICU length of stay, surgical procedures, insurance status, and discharge disposition. Inhalation injury was diagnosed based on exposure to smoke in an enclosed space and clinical findings. These included carboxyhemoglobin levels and bronchoscopic findings. Preinjury comorbidities were assessed by reviewing the patient history documentation. Frailty
scores were assessed using the Canadian Study of Health and Aging clinical frailty scale (Figure 1).9 Frailty scores were determined retrospectively by two burn-practioners and an average frailty score was used for comparisons. Admission data, social work notes, discharge planning notes, and physical therapy evaluations were used to determine preinjury frailty. R statistical package (www.r-project.org) was used to analyze the data. Inter-rater agreement was assessed by Krippendorff’s alpha. Continuous variable comparisons between two groups was performed using the two-sample Student’s t-test for continuous data such as age, ICU length of stay, hospital length of stay, ventilator days, burn size, number of operations, and frailty score. The Chi-square test was used to assess association between discrete categorical variables. Multivariate linear regression analysis was used to determine associations between continuous outcome variables and independent continuous and categorical predictor variables. Multivariate linear regression analysis was performed for frailty scores (continuous variable). Predictor variables included in the linear model included age, TBSA, gender, presence of inhalation injury, length of hospital stay, length of ICU stay, number of operations, mortality, and discharge disposition. Multivariate logistic regression analysis was performed to determine associations between categorical outcome variables and independent continuous and categorical predictor variables. Multivariate logistic regression analysis was performed for mortality (categorical variable). Predictor variables for this model included mean frailty scores, age, gender, TBSA, hospital length of stay, presence of inhalation injury, ICU length of stay, ventilator days, and number of operations.
RESULTS A total of 95 burn-injured patients 65 years and older who were admitted to the hospital were included in the study. Six patients were excluded from the analysis because they were determined to have a nonsurvivable injury at the time of admission. The demographic data for remaining 89 patients is presented in Table 2. The mean age was 75.26 ± 8.14 years and there were 27 women (30.3%) and 62 men (69.7%). The mean age for men (74.9 ± 8) and women (75.9 ± 8) was not significantly different. The mean TBSA burned was 9.64 ± 9.06% with a full thickness TBSA of 5.38%±7.9%. Flame burns were the most common cause of injury accounting for 60.7% (54) of patients in this study. Scalds were second most common with 24.7% (22 patients). Inhalation injury was present in 12.3% of patients.
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Table 1. Canadian Study on Health frailty score Score 1—Very fit 2—Well 3—Well with treated comorbid disease 4—Apparently vulnerable 5—Mildly frail 6—Moderately frail 7—Severely frail
Description Robust, active, energetic, well-motivated, and fit. Without active disease, but less fit than people in category one. Disease symptoms are well controlled compared with those in category four. Although not frankly dependent, these people commonly complain of being “slowed up” or have disease symptoms. With limited dependence on others for instrumental activities of daily living. Help is needed with both instrumental and noninstrumental activities of daily living. Completely dependent on others for the activities of daily living, or terminally ill.
Mean days of mechanical ventilation were 3.7 ± 10.7 (range 0–67). Patients were in the ICU an average of 12.09 ± 15.66 days (0–99 days). The most common discharge disposition was home with no home care with 46 (51.7%) patients. Twenty-five (28%) patients required either SNF or extended care facility. The vast majority of patients had medical insurance (97.8%) with the highest number having Medicare (51 [57.3%]). Seventy-five of 89 patients had at least one comorbid illness. The most common comorbidities were hypertension (55%), diabetes (25.8%), current smoker (23.6%), respiratory disease (21.3%), congestive heart failure (20.2%), and alcoholism (15.7%). Nine of 89 patients died (10.1%). Frailty scores were assessed for each patient as described above. The percent agreement between the two raters was 42% and the Krippendorff’s alpha was 0.27. Analysis of the data was performed with each independent frailty assessments as well as the mean frailty assessment (Table 3). The mean frailty score (FS) of the entire population was 4.46 ± 1.25 (1.5–7). Nonsurvivors had significantly higher FS compared to survivors (5.2 ± 1.2 vs 4.4 ± 1.2) (Table 3). Additionally FS were also significantly higher in patients discharged to SNFs (5.34 ± 0.9) compared to those Table 2. Patient demographics Demographic Age (range) Female Male TBSA TBSA second degree TBSA third degree Inhalation injury Length of hospital stay Length of ICU stay Ventilator days Number of operations Frailty score
Value 75.26 ± 8.14 (65–95) 30.30% 69.70% 9.64 ± 9.06 (0.5–50%) 4.33 ± 5.29 (0–23%) 5.38 ± 7.89 (0–42%) 12.30% 15.1 ± 16.7 (1–107) 12.09 ± 15.66 (0–99) 3.7 ± 10.7 (0–67) 0.56 ± 0.75 (0–3) 4.46 ± 1.25 (1.5–7)
TBSA, total body surface area burn injured; ICU, intensive care unit.
who were discharged home (4.1 ± 1.2) or to physical rehabilitation facilities (4 ± 1.5). There were no differences in FS between those who had inhalation injury and those who did not (4.7 ± 1.3 vs 4.4 ± 0.7). Using multivariate linear regression analysis modeling, survivors were independently associated with a significantly lower frailty score (B = −1.3) compared to nonsurvivors. In addition to this, age (B = 0.04) and discharge to SNF (B = 1.2) are independently associated with a higher FS (Table 4). Multivariate logistic regression analysis revealed high admission FS independently increased the risk of discharge to SNF (odds ratio of 2.5 [1.3–4.8, 95% confidence interval]) (Table 5). Additionally, FS increased the risk of mortality (odds ratio of 1.67 [1.01–2.7, 95% confidence interval]) (Table 6).
DISCUSSION Chronologic age does not always reflect physiologic age and preinjury physiologic condition appears to have a significant impact on recovery from acute medical conditions. Rockwood et al9 in 2005 developed the seven point clinical frailty scale as a way of measuring frailty based on clinical judgment. They validated the scale against a rules based assessment and a summation of number of impairments and found that the clinical judgment based scale was valid and performed as well or better than other established measures at predicting death and entry into an institutional facility. In correlation, elderly patients admitted to acute medical units who are moderately to severely frail on admission have a higher risk of dying.10 For elderly surgical patients, higher presurgical frailty increases the risk of postsurgical complications, lengthens hospital stay, and increases the risk of discharge to a SNF.11 Additionally, frail elderly surgical patients are at higher risk of poor long-term postsurgical survival.12 For elderly trauma patients, a higher per-injury frailty index predicted an unfavorable discharge (SNF or death).13 Thus, physiologic condition for the elderly has a significant impact
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Table 3. Association of frailty scores with clinical variables Demographic
Frailty Score Rater 1
Frailty Score Rater 2
Frailty Score Mean
4.08 ± 1.33 4.7 ± 1.29* 4.18 ± 1.07 4,29 ± 1.39 4.2 ± 1.34 5 ± 1.22 3.92 ± 1.18 4 ± 1.78 5.16 ± 1.28* 4 ± 1
4.37 ± 1.36 5.22 ± 1.22* 5.27 ± 1.01 4.53 ± 1.39 4.55 ± 1.33 5.33 ± 1.58 4.32 ± 1.39 4 ± 1.26 5.52 ± 0.96* 4 ± 1
4.23 ± 1.24 4.98 ± 1.12* 4.42 ± 0.72 4.72 ± 1.3 4.38 ± 1.24 5.17 ± 1.17* 4.12 ± 1.19 4 ± 1.45 5.34 ± 0.92* 4 ± 0.87
Male Female Inhalation injury (yes) Inhalation injury (no) Survivors Nonsurvivors Discharge to home (no HH) Discharge to home (w HH) Discharge to SNF Discharge to physical rehabilitation HH, home health support; SNF, skilled nursing facility. All mean values are represented by mean ± SD. *P < .05.
on the morbidity and mortality in medical, surgical, and injured patients. Preinjury physiologic condition also plays an important role in the outcomes of elderly burn patients. In particular, patients who survive their burn injury had significantly less comorbid illnesses than nonsurvivors.14 However, an inventory of comorbid illnesses does not provide enough granular data on physiologic capacity. Preinjury frailty assessment provides the possibility of predicting recovery from burn injury. Frailty assessments of elderly burn patients with a %TBSA of greater than 10%, found that patients with favorable frailty scores may better be able to survive a burn injury.8 Survivors had a median frailty of three compared to nonsurvivors who had a median frailty of five.8 Applying the same frailty score to our patient population also revealed an association between higher frailty score and mortality. We found that higher frailty scores are associated Table 4. Multivariate linear regression analysis for frailty score Variable
B (FS1)
B (FS2)
B (FS Mean)
Hospital length of stay TBSA Inhalation injury ICU length of stay Ventilator days Age Operations Survivors Discharge to SNF Male gender
−0.005 −0.014 −0.68 0.03 −0.002 0.02 −0.38 −1.53* 1.26* −0.44*
−0.003 −0.034 0.37 0.03 −0.02 0.04* −0.1 −1.08* 1.09* −0.63
−0.004 −0.024 −0.151 0.03 −0.01 0.04* −0.24 −1.3* 1.18* −0.53*
TBSA, total body surface area burn injured; SNF, skilled nursing facility; B, slope of the regression line; FS1, frailty score from rater 1; FS2, frailty score from rater 2; FS Mean, mean frailty score. *P < .05.
with mortality for all admitted elderly burn patients. The mean frailty score for nonsurvivors in our study was 5.17 ± 1.17, which was significantly higher than the frailty score in survivors (4.38 ± 1.24). Additionally, an elevated frailty score was independently associated with an increased risk of mortality (odds ratio 1.67). Our mortality was only 10.1% compared with 57.1% in their study. This is likely because the average %TBSA in our group was 9.64% with only 12.3% having inhalation injury while the %TBSA in their survivors and nonsurvivors was greater at 28.1% and 37.7%, respectively and the amount of inhalation injury was 16.7% and 41.6%. Additionally, independent of age, % TBSA, and inhalation injury, higher frailty scores were associated with death and predicted a higher chance of discharge to institutional care such as a SNF and a higher risk of mortality. The group from the UK (Masud et al, 2013) did not look at the disposition of their patients, but ours found that increased frailty score was associated with a greater likelihood of requiring placement in a SNF or an extended care facility. It is possible that this was not an issue given the different methods of health care delivery in our two countries. In our elderly Table 5. Multivariate logistic regression analysis of the risk of discharge to a skilled nursing facility Variable Frailty score rater 1 Frailty score rater 2 Frailty score mean LOS Age TBSA
Odds Ratio
95% CI
2.1 2.2 2.5 1.18 1.08 1.06
1.2–3.6 1.2–4.1 1.3–4.8 0.99–1.4 0.99–1.18 0.93–1.21
LOS, length of hospital stay; TBSA, total body surface area burn injured; CI, confidence interval.
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Table 6. Multivariate logistic regression analysis of the risk of mortality Variable Frailty score rater 1 Frailty score rater 2 Frailty score mean LOS Age TBSA
Odds Ratio
95% CI
1.6 1.5 1.67 1.17 1.06 1.03
1.01–2.4 0.93–2.4 1.01–2.7 1.04–1.33 0.98–1.14 0.95–1.13
LOS, length of hospital stay; TBSA, total body surface area burn injured; CI, confidence interval.
patient population, it appears that even a small burn can have a significant impact on the patient’s functional status and ability to live independently after their injury. Thus, frailty assessments at admission can be used to identify elderly burn patients at risk for poor outcomes. Additionally, risk stratifying elderly burn patients by frailty scores would provide a better analytic tool to determine quality of care across varied institutions. However, frailty assessments for surgical and injured elderly patients have not been used in traditional quality measures for outcomes. This is in some part due to the wide variety of frailty assessments used in various injury and surgical settings. For example, in a recent prospective study of elderly trauma patients, a 15 variable trauma specific frailty index was tested and showed that patients with a higher index had an unfavorable discharge disposition.15 While this index was predictive of outcome, it involved an extensive evaluation of daily life activities and premorbid medical condition. Furthermore, this index was paired down from a 50-item frailty index that predicted hospital discharge in elderly trauma patients.13 In a study of elderly patients undergoing elective surgery, a frailty index was composed of more than 25 variables including a geriatric analysis, medical condition, mental status, and laboratory analysis.16 For elderly patients undergoing aortic valve surgery, frailty scores based on gait, strength, nutrition, and activity were associated with increased mortality within 1 year of surgery.17 Other studies of elective elderly surgical patient showed that frailty scores comprising of weakness, weight loss, exhaustion, low physical activity, mood, continence, social support, gait, and functional performance were predictive of the need for a SNF on discharge and postoperative complications.11,18 The variability and complexity of many of these frailty assessments ultimately limits their widespread use. Moreover, in burn injury, it is often not feasible to use many of the previously tested frailty assessments because of either the complexity of the assessment or the lack of data needed to complete the
assessment. The frailty assessment developed from the Canadian Study of Health and Aging does not require much of the information that is needed in many other frailty assessments. There is no geriatric assessment or laboratory analysis required to determine a frailty score and several studies have validated the frailty score for outcomes for hospitalized elderly patients.19 For elderly burn patient assessments, the Canadian Study of Health and Aging (CSHA) frailty score can be calculated at admission from information from patients, family, caregivers, and friends. The ease in calculating CSHA frailty score makes it a potentially useful tool for multi-institutional quality assessments for elderly patients. There are several limitations to our study. First this was a retrospective review and therefore the data collected was not specifically designed to assess for preinjury frailty. Second, frailty assessments were made based on several sources of admission data including the admission history, admission laboratory data, physical therapy notes, discharge planner notes, and social worker notes. Third, our inter-rater percent agreement was only 42% with a Krippendorff’s alpha value of 0.27. However data analysis using the mean frailty scores from each clinical assessor yielded similar results to the data analysis using the combined mean frailty scores. Overall, despite these limitations, preinjury frailty assessments appear to identify high-risk elderly burn patients. Admission frailty scores can be used to developed predictive models for outcomes for elderly burn patients. More importantly, frailty assessments can be used to research treatment interventions to improve outcomes for these high-risk elderly burn patients. The next step in the frailty assessments for elderly burn injury should be a multicenter prospective study. This study should not only assess the predictive potential of frailty scores but also analyze whether frailty scores improve the accuracy of validated measures of burn outcomes in the elderly. Ultimately, if frailty scores are shown to improve the prediction accuracy for elderly burn outcomes, then a frailty assessment should be collected in the National Burn Registry in order to establish benchmarks for quality in the treatment of elderly burn injury. REFERENCES 1. Werner CA. The Older Population: 2010. U.S. Census Bureau; 2010. Available at http://www.census.gov/prod/ cen2010/briefs/c2010br-09.pdf. 2. Solanki NS, Greenwood JE, Mackie IP, Kavanagh S, Penhall R. Social issues prolong elderly burn patient hospitalization. J Burn Care Res 2011;32:387–91.
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3. Palmieri TL, Molitor F, Chan G, et al. Long-term functional outcomes in the elderly after burn injury. J Burn Care Res 2012;33:497–503. 4. Klein MB, Lezotte DC, Heltshe S, et al. Functional and psychosocial outcomes of older adults after burn injury: results from a multicenter database of severe burn injury. J Burn Care Res 2011;32:66–78. 5. Dokter J, Meijs J, Oen IM, van Baar ME, van der Vlies CH, Boxma H. External validation of the revised Baux score for the prediction of mortality in patients with acute burn injury. J Trauma Acute Care Surg 2014;76:840–5. 6. Hussain A, Choukairi F, Dunn K. Predicting survival in thermal injury: a systematic review of methodology of composite prediction models. Burns 2013;39:835–50. 7. Lundgren RS, Kramer CB, Rivara FP, et al. Influence of comorbidities and age on outcome following burn injury in older adults. J Burn Care Res 2009;30:307–14. 8. Masud D, Norton S, Smailes S, Shelley O, Philp B, Dziewulski P. The use of a frailty scoring system for burns in the elderly. Burns 2013;39:30–6. 9. Rockwood K, Song X, MacKnight C, et al. A global clinical measure of fitness and frailty in elderly people. CMAJ 2005;173:489–95. 10. Conroy S, Dowsing T. The ability of frailty to predict outcomes in older people attending an acute medical unit. Acute Med 2013;12:74–6. 11. Makary MA, Segev DL, Pronovost PJ, et al. Frailty as a predictor of surgical outcomes in older patients. J Am Coll Surg 2010;210:901–8.
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12. Lee DH, Buth KJ, Martin BJ, Yip AM, Hirsch GM. Frail patients are at increased risk for mortality and prolonged institutional care after cardiac surgery. Circulation 2010;121:973–8. 13. Joseph B, Pandit V, Rhee P, et al. Predicting hospi tal discharge disposition in geriatric trauma patients: is frailty the answer? J Trauma Acute Care Surg 2014;76: 196–200. 14. Baux S, Mimoun M, Saade H, et al. Burns in the elderly. Burns 1989;15:239–40. 15. Joseph B, Pandit V, Zangbar B, et al. Validating trauma-specific frailty index for geriatric trauma patients: a prospective analysis. J Am Coll Surg 2014;219:10–17.e1. 16. Kim SW, Han HS, Jung HW, et al. Multidimensional frailty score for the prediction of postoperative mortality risk. JAMA Surg 2014;149:633–40. 17. Green P, Woglom AE, Genereux P, et al. The impact of frailty status on survival after transcatheter aortic valve replacement in older adults with severe aortic stenosis: a single-center experience. JACC Cardiovasc Interv 2012;5:974–81. 18. Dasgupta M, Rolfson DB, Stolee P, Borrie MJ, Speechley M. Frailty is associated with postoperative complications in older adults with medical problems. Arch Gerontol Geriatr 2009;48:78–83. 19. Mitnitski A, Song X, Skoog I, et al. Relative fitness and frailty of elderly men and women in developed countries and their relationship with mortality. J Am Geriatr Soc 2005;53:2184–9.
Frailty Score on Admission Predicts Outcomes in Elderly Burn Injury Kathleen S. Romanowski, MD, Alura Barsun, FNP-C, Tina L. Pamlieri, MD, FACS, FCCM, David G. Greenhalgh, MD, FACS, Soman Sen, MD, FACS
With longer life expectancy, the number of burn injuries in the elderly continues to increase. Prediction of outcomes for the elderly is complicated by preinjury physical fitness and comorbid illness. The authors hypothesize that admission frailty assessment would be predictive of outcomes in the elderly burn population. Our primary aim was to determine if higher frailty scores were associated with higher risk of mortality for elderly burn patients. The secondary aims were to assess if higher frailty scores were associated with increased length of stay, increased needs for mechanical ventilation and poor discharge disposition. A 2-year retrospective chart review was performed of all admitted acute burn patients 65 years or older. Data collected included: age, gender, %TBSA of burn injury, presence of inhalation injury, in hospital mortality, hospital length of stay, ventilator days, ICU length of stay, surgical procedures, insurance status, and discharge disposition. Frailty scores were assessed from admission data and calculated using the Canadian Study of Health and Aging clinical frailty scale. A total of 89 patients met entry criteria. Mean age was 75.3 ± 8.1 years and consisted of 62 men and 27 women. Mean %TBSA was 9.6 ± 9.1% and mean frailty score (FS) was 4.5 ± 1.2. Eighty patients survived to discharge and nine died. Nonsurvivors had significantly higher FS compared to survivors (5.2 ± 1.2 vs 4.4 ± 1.2). FS were also significantly higher in patients discharged to skilled nursing facilities (SNF) (5.34 ± 0.9) compared to those who were discharged home (4.1 ± 1.2) or to physical rehabilitation facilities (4 ± 1.5). Multivariate linear regression analysis revealed that age (B = 0.04) and discharge to SNF (B = 1.2) are independently associated with higher FS. However, survivors were independently associated with a significantly lower FS (B = −1.3). Multivariate logistic regression analysis revealed high admission FS independently increased the risk of discharge to SNF (odds ratio of 2.5 [1.3–4.8, 95% confidence interval]) and increased the risk of mortality (odds ratio of 1.67 [1.01–2.7, 95% confidence interval]). Frailty scores on admission allow for a more complete assessment of elderly patients and can be used to establish benchmark models for burn injury outcomes. In addition FS can be used as a research tool to improve outcomes for elderly burn injured patients. (J Burn Care Res 2015;36:1–6)
The number of elderly in the United States is now larger than it has ever been in history. The 2010 census reveals that there are 40.3 million people age 65 older. This is a 5.3% increase compared to the 2000 census.1 As the elderly population grows From the University of California Davis, Shriners Hospitals for Children, Sacramento, California. Address correspondence to Soman Sen, MD, University of California Davis, Shriners Hospitals for Children, 2425 Stockton Blvd. Suite 718, Sacramento, California 95817. Email: soman. [email protected]. Copyright © 2014 by the American Burn Association 1559-047X/2015 DOI: 10.1097/BCR.0000000000000190
so does the number of elderly burn victims. However, despite an overall improvement in outcomes from burn injuries, elderly burn victims suffer from worse outcomes. Elderly burn patients have much longer hospital admissions compared to younger adult burn patients despite similar extents of burn injury.2 More concerning is the evidence that independent of the extent of burn injury, elderly burn patients who are discharged to skilled nursing facilities (SNFs) die more often and have poor long-term physical function.3 Furthermore, significant physical and psychological impairments are present in elderly burn patients up to 1 year after discharge.4 1
Journal of Burn Care & Research January/February 2015
2 Romanowski et al
Traditional models to estimate burn outcomes have used age and total body surface area % (%TBSA) as their main determinants.5 As burn care has evolved new models have been developed that included a wide variety of factors including presence of full thickness burn, inhalation injury, and gender in addition to age and %TBSA.6 In the elderly there have even been attempts to examine the extent to which comorbidities affect mortality.7 Despite the many methods for predicting mortality, none of these models takes into consideration the impact of preinjury physiologic condition. A recent investigation by Masud et al8 in 2013 examined the effects of preinjury physical condition on mortality and outcomes using the Canadian Study of Health and Aging clinical frailty scale. They were able to demonstrate that high frailty scores (poor preinjury physical condition) accurately predicted mortality and poor outcomes in elderly burn patients (Table 1). While this study expanded on the idea that physiologic age was more important than chronologic age in predicting outcomes in elderly burn patients the study only included burn injuries that were larger than 10% TBSA (total burn surface area). Given this, the aim for this investigation is to determine the utility of preinjury frailty assessment in determining outcomes for all elderly burn victims. We hypothesize that a high preinjury frailty score will be predictive of a poor outcome and higher mortality after a burn injury in elderly patients.
METHODS After approval from the local institutional review board, we performed a retrospective review of all patients 65 years old and greater who were admitted to the hospital with a thermal injury from June 2011 to May 2013. Patients were identified through our local Trauma Registry modified for American College of Surgery (TRACS) database. Patients were excluded if they were determined to have suffered a nonsurvivable injury. This assessment was made at the time of admission by the admitting burn surgeon and was based on the extent of burn injury and age. Data collected included: age, gender, % TBSA of burn injury, presence of inhalation injury, in hospital mortality, hospital length of stay, ventilator days, ICU length of stay, surgical procedures, insurance status, and discharge disposition. Inhalation injury was diagnosed based on exposure to smoke in an enclosed space and clinical findings. These included carboxyhemoglobin levels and bronchoscopic findings. Preinjury comorbidities were assessed by reviewing the patient history documentation. Frailty
scores were assessed using the Canadian Study of Health and Aging clinical frailty scale (Figure 1).9 Frailty scores were determined retrospectively by two burn-practioners and an average frailty score was used for comparisons. Admission data, social work notes, discharge planning notes, and physical therapy evaluations were used to determine preinjury frailty. R statistical package (www.r-project.org) was used to analyze the data. Inter-rater agreement was assessed by Krippendorff’s alpha. Continuous variable comparisons between two groups was performed using the two-sample Student’s t-test for continuous data such as age, ICU length of stay, hospital length of stay, ventilator days, burn size, number of operations, and frailty score. The Chi-square test was used to assess association between discrete categorical variables. Multivariate linear regression analysis was used to determine associations between continuous outcome variables and independent continuous and categorical predictor variables. Multivariate linear regression analysis was performed for frailty scores (continuous variable). Predictor variables included in the linear model included age, TBSA, gender, presence of inhalation injury, length of hospital stay, length of ICU stay, number of operations, mortality, and discharge disposition. Multivariate logistic regression analysis was performed to determine associations between categorical outcome variables and independent continuous and categorical predictor variables. Multivariate logistic regression analysis was performed for mortality (categorical variable). Predictor variables for this model included mean frailty scores, age, gender, TBSA, hospital length of stay, presence of inhalation injury, ICU length of stay, ventilator days, and number of operations.
RESULTS A total of 95 burn-injured patients 65 years and older who were admitted to the hospital were included in the study. Six patients were excluded from the analysis because they were determined to have a nonsurvivable injury at the time of admission. The demographic data for remaining 89 patients is presented in Table 2. The mean age was 75.26 ± 8.14 years and there were 27 women (30.3%) and 62 men (69.7%). The mean age for men (74.9 ± 8) and women (75.9 ± 8) was not significantly different. The mean TBSA burned was 9.64 ± 9.06% with a full thickness TBSA of 5.38%±7.9%. Flame burns were the most common cause of injury accounting for 60.7% (54) of patients in this study. Scalds were second most common with 24.7% (22 patients). Inhalation injury was present in 12.3% of patients.
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Table 1. Canadian Study on Health frailty score Score 1—Very fit 2—Well 3—Well with treated comorbid disease 4—Apparently vulnerable 5—Mildly frail 6—Moderately frail 7—Severely frail
Description Robust, active, energetic, well-motivated, and fit. Without active disease, but less fit than people in category one. Disease symptoms are well controlled compared with those in category four. Although not frankly dependent, these people commonly complain of being “slowed up” or have disease symptoms. With limited dependence on others for instrumental activities of daily living. Help is needed with both instrumental and noninstrumental activities of daily living. Completely dependent on others for the activities of daily living, or terminally ill.
Mean days of mechanical ventilation were 3.7 ± 10.7 (range 0–67). Patients were in the ICU an average of 12.09 ± 15.66 days (0–99 days). The most common discharge disposition was home with no home care with 46 (51.7%) patients. Twenty-five (28%) patients required either SNF or extended care facility. The vast majority of patients had medical insurance (97.8%) with the highest number having Medicare (51 [57.3%]). Seventy-five of 89 patients had at least one comorbid illness. The most common comorbidities were hypertension (55%), diabetes (25.8%), current smoker (23.6%), respiratory disease (21.3%), congestive heart failure (20.2%), and alcoholism (15.7%). Nine of 89 patients died (10.1%). Frailty scores were assessed for each patient as described above. The percent agreement between the two raters was 42% and the Krippendorff’s alpha was 0.27. Analysis of the data was performed with each independent frailty assessments as well as the mean frailty assessment (Table 3). The mean frailty score (FS) of the entire population was 4.46 ± 1.25 (1.5–7). Nonsurvivors had significantly higher FS compared to survivors (5.2 ± 1.2 vs 4.4 ± 1.2) (Table 3). Additionally FS were also significantly higher in patients discharged to SNFs (5.34 ± 0.9) compared to those Table 2. Patient demographics Demographic Age (range) Female Male TBSA TBSA second degree TBSA third degree Inhalation injury Length of hospital stay Length of ICU stay Ventilator days Number of operations Frailty score
Value 75.26 ± 8.14 (65–95) 30.30% 69.70% 9.64 ± 9.06 (0.5–50%) 4.33 ± 5.29 (0–23%) 5.38 ± 7.89 (0–42%) 12.30% 15.1 ± 16.7 (1–107) 12.09 ± 15.66 (0–99) 3.7 ± 10.7 (0–67) 0.56 ± 0.75 (0–3) 4.46 ± 1.25 (1.5–7)
TBSA, total body surface area burn injured; ICU, intensive care unit.
who were discharged home (4.1 ± 1.2) or to physical rehabilitation facilities (4 ± 1.5). There were no differences in FS between those who had inhalation injury and those who did not (4.7 ± 1.3 vs 4.4 ± 0.7). Using multivariate linear regression analysis modeling, survivors were independently associated with a significantly lower frailty score (B = −1.3) compared to nonsurvivors. In addition to this, age (B = 0.04) and discharge to SNF (B = 1.2) are independently associated with a higher FS (Table 4). Multivariate logistic regression analysis revealed high admission FS independently increased the risk of discharge to SNF (odds ratio of 2.5 [1.3–4.8, 95% confidence interval]) (Table 5). Additionally, FS increased the risk of mortality (odds ratio of 1.67 [1.01–2.7, 95% confidence interval]) (Table 6).
DISCUSSION Chronologic age does not always reflect physiologic age and preinjury physiologic condition appears to have a significant impact on recovery from acute medical conditions. Rockwood et al9 in 2005 developed the seven point clinical frailty scale as a way of measuring frailty based on clinical judgment. They validated the scale against a rules based assessment and a summation of number of impairments and found that the clinical judgment based scale was valid and performed as well or better than other established measures at predicting death and entry into an institutional facility. In correlation, elderly patients admitted to acute medical units who are moderately to severely frail on admission have a higher risk of dying.10 For elderly surgical patients, higher presurgical frailty increases the risk of postsurgical complications, lengthens hospital stay, and increases the risk of discharge to a SNF.11 Additionally, frail elderly surgical patients are at higher risk of poor long-term postsurgical survival.12 For elderly trauma patients, a higher per-injury frailty index predicted an unfavorable discharge (SNF or death).13 Thus, physiologic condition for the elderly has a significant impact
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Table 3. Association of frailty scores with clinical variables Demographic
Frailty Score Rater 1
Frailty Score Rater 2
Frailty Score Mean
4.08 ± 1.33 4.7 ± 1.29* 4.18 ± 1.07 4,29 ± 1.39 4.2 ± 1.34 5 ± 1.22 3.92 ± 1.18 4 ± 1.78 5.16 ± 1.28* 4 ± 1
4.37 ± 1.36 5.22 ± 1.22* 5.27 ± 1.01 4.53 ± 1.39 4.55 ± 1.33 5.33 ± 1.58 4.32 ± 1.39 4 ± 1.26 5.52 ± 0.96* 4 ± 1
4.23 ± 1.24 4.98 ± 1.12* 4.42 ± 0.72 4.72 ± 1.3 4.38 ± 1.24 5.17 ± 1.17* 4.12 ± 1.19 4 ± 1.45 5.34 ± 0.92* 4 ± 0.87
Male Female Inhalation injury (yes) Inhalation injury (no) Survivors Nonsurvivors Discharge to home (no HH) Discharge to home (w HH) Discharge to SNF Discharge to physical rehabilitation HH, home health support; SNF, skilled nursing facility. All mean values are represented by mean ± SD. *P < .05.
on the morbidity and mortality in medical, surgical, and injured patients. Preinjury physiologic condition also plays an important role in the outcomes of elderly burn patients. In particular, patients who survive their burn injury had significantly less comorbid illnesses than nonsurvivors.14 However, an inventory of comorbid illnesses does not provide enough granular data on physiologic capacity. Preinjury frailty assessment provides the possibility of predicting recovery from burn injury. Frailty assessments of elderly burn patients with a %TBSA of greater than 10%, found that patients with favorable frailty scores may better be able to survive a burn injury.8 Survivors had a median frailty of three compared to nonsurvivors who had a median frailty of five.8 Applying the same frailty score to our patient population also revealed an association between higher frailty score and mortality. We found that higher frailty scores are associated Table 4. Multivariate linear regression analysis for frailty score Variable
B (FS1)
B (FS2)
B (FS Mean)
Hospital length of stay TBSA Inhalation injury ICU length of stay Ventilator days Age Operations Survivors Discharge to SNF Male gender
−0.005 −0.014 −0.68 0.03 −0.002 0.02 −0.38 −1.53* 1.26* −0.44*
−0.003 −0.034 0.37 0.03 −0.02 0.04* −0.1 −1.08* 1.09* −0.63
−0.004 −0.024 −0.151 0.03 −0.01 0.04* −0.24 −1.3* 1.18* −0.53*
TBSA, total body surface area burn injured; SNF, skilled nursing facility; B, slope of the regression line; FS1, frailty score from rater 1; FS2, frailty score from rater 2; FS Mean, mean frailty score. *P < .05.
with mortality for all admitted elderly burn patients. The mean frailty score for nonsurvivors in our study was 5.17 ± 1.17, which was significantly higher than the frailty score in survivors (4.38 ± 1.24). Additionally, an elevated frailty score was independently associated with an increased risk of mortality (odds ratio 1.67). Our mortality was only 10.1% compared with 57.1% in their study. This is likely because the average %TBSA in our group was 9.64% with only 12.3% having inhalation injury while the %TBSA in their survivors and nonsurvivors was greater at 28.1% and 37.7%, respectively and the amount of inhalation injury was 16.7% and 41.6%. Additionally, independent of age, % TBSA, and inhalation injury, higher frailty scores were associated with death and predicted a higher chance of discharge to institutional care such as a SNF and a higher risk of mortality. The group from the UK (Masud et al, 2013) did not look at the disposition of their patients, but ours found that increased frailty score was associated with a greater likelihood of requiring placement in a SNF or an extended care facility. It is possible that this was not an issue given the different methods of health care delivery in our two countries. In our elderly Table 5. Multivariate logistic regression analysis of the risk of discharge to a skilled nursing facility Variable Frailty score rater 1 Frailty score rater 2 Frailty score mean LOS Age TBSA
Odds Ratio
95% CI
2.1 2.2 2.5 1.18 1.08 1.06
1.2–3.6 1.2–4.1 1.3–4.8 0.99–1.4 0.99–1.18 0.93–1.21
LOS, length of hospital stay; TBSA, total body surface area burn injured; CI, confidence interval.
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Table 6. Multivariate logistic regression analysis of the risk of mortality Variable Frailty score rater 1 Frailty score rater 2 Frailty score mean LOS Age TBSA
Odds Ratio
95% CI
1.6 1.5 1.67 1.17 1.06 1.03
1.01–2.4 0.93–2.4 1.01–2.7 1.04–1.33 0.98–1.14 0.95–1.13
LOS, length of hospital stay; TBSA, total body surface area burn injured; CI, confidence interval.
patient population, it appears that even a small burn can have a significant impact on the patient’s functional status and ability to live independently after their injury. Thus, frailty assessments at admission can be used to identify elderly burn patients at risk for poor outcomes. Additionally, risk stratifying elderly burn patients by frailty scores would provide a better analytic tool to determine quality of care across varied institutions. However, frailty assessments for surgical and injured elderly patients have not been used in traditional quality measures for outcomes. This is in some part due to the wide variety of frailty assessments used in various injury and surgical settings. For example, in a recent prospective study of elderly trauma patients, a 15 variable trauma specific frailty index was tested and showed that patients with a higher index had an unfavorable discharge disposition.15 While this index was predictive of outcome, it involved an extensive evaluation of daily life activities and premorbid medical condition. Furthermore, this index was paired down from a 50-item frailty index that predicted hospital discharge in elderly trauma patients.13 In a study of elderly patients undergoing elective surgery, a frailty index was composed of more than 25 variables including a geriatric analysis, medical condition, mental status, and laboratory analysis.16 For elderly patients undergoing aortic valve surgery, frailty scores based on gait, strength, nutrition, and activity were associated with increased mortality within 1 year of surgery.17 Other studies of elective elderly surgical patient showed that frailty scores comprising of weakness, weight loss, exhaustion, low physical activity, mood, continence, social support, gait, and functional performance were predictive of the need for a SNF on discharge and postoperative complications.11,18 The variability and complexity of many of these frailty assessments ultimately limits their widespread use. Moreover, in burn injury, it is often not feasible to use many of the previously tested frailty assessments because of either the complexity of the assessment or the lack of data needed to complete the
assessment. The frailty assessment developed from the Canadian Study of Health and Aging does not require much of the information that is needed in many other frailty assessments. There is no geriatric assessment or laboratory analysis required to determine a frailty score and several studies have validated the frailty score for outcomes for hospitalized elderly patients.19 For elderly burn patient assessments, the Canadian Study of Health and Aging (CSHA) frailty score can be calculated at admission from information from patients, family, caregivers, and friends. The ease in calculating CSHA frailty score makes it a potentially useful tool for multi-institutional quality assessments for elderly patients. There are several limitations to our study. First this was a retrospective review and therefore the data collected was not specifically designed to assess for preinjury frailty. Second, frailty assessments were made based on several sources of admission data including the admission history, admission laboratory data, physical therapy notes, discharge planner notes, and social worker notes. Third, our inter-rater percent agreement was only 42% with a Krippendorff’s alpha value of 0.27. However data analysis using the mean frailty scores from each clinical assessor yielded similar results to the data analysis using the combined mean frailty scores. Overall, despite these limitations, preinjury frailty assessments appear to identify high-risk elderly burn patients. Admission frailty scores can be used to developed predictive models for outcomes for elderly burn patients. More importantly, frailty assessments can be used to research treatment interventions to improve outcomes for these high-risk elderly burn patients. The next step in the frailty assessments for elderly burn injury should be a multicenter prospective study. This study should not only assess the predictive potential of frailty scores but also analyze whether frailty scores improve the accuracy of validated measures of burn outcomes in the elderly. Ultimately, if frailty scores are shown to improve the prediction accuracy for elderly burn outcomes, then a frailty assessment should be collected in the National Burn Registry in order to establish benchmarks for quality in the treatment of elderly burn injury. REFERENCES 1. Werner CA. The Older Population: 2010. U.S. Census Bureau; 2010. Available at http://www.census.gov/prod/ cen2010/briefs/c2010br-09.pdf. 2. Solanki NS, Greenwood JE, Mackie IP, Kavanagh S, Penhall R. Social issues prolong elderly burn patient hospitalization. J Burn Care Res 2011;32:387–91.
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3. Palmieri TL, Molitor F, Chan G, et al. Long-term functional outcomes in the elderly after burn injury. J Burn Care Res 2012;33:497–503. 4. Klein MB, Lezotte DC, Heltshe S, et al. Functional and psychosocial outcomes of older adults after burn injury: results from a multicenter database of severe burn injury. J Burn Care Res 2011;32:66–78. 5. Dokter J, Meijs J, Oen IM, van Baar ME, van der Vlies CH, Boxma H. External validation of the revised Baux score for the prediction of mortality in patients with acute burn injury. J Trauma Acute Care Surg 2014;76:840–5. 6. Hussain A, Choukairi F, Dunn K. Predicting survival in thermal injury: a systematic review of methodology of composite prediction models. Burns 2013;39:835–50. 7. Lundgren RS, Kramer CB, Rivara FP, et al. Influence of comorbidities and age on outcome following burn injury in older adults. J Burn Care Res 2009;30:307–14. 8. Masud D, Norton S, Smailes S, Shelley O, Philp B, Dziewulski P. The use of a frailty scoring system for burns in the elderly. Burns 2013;39:30–6. 9. Rockwood K, Song X, MacKnight C, et al. A global clinical measure of fitness and frailty in elderly people. CMAJ 2005;173:489–95. 10. Conroy S, Dowsing T. The ability of frailty to predict outcomes in older people attending an acute medical unit. Acute Med 2013;12:74–6. 11. Makary MA, Segev DL, Pronovost PJ, et al. Frailty as a predictor of surgical outcomes in older patients. J Am Coll Surg 2010;210:901–8.
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12. Lee DH, Buth KJ, Martin BJ, Yip AM, Hirsch GM. Frail patients are at increased risk for mortality and prolonged institutional care after cardiac surgery. Circulation 2010;121:973–8. 13. Joseph B, Pandit V, Rhee P, et al. Predicting hospi tal discharge disposition in geriatric trauma patients: is frailty the answer? J Trauma Acute Care Surg 2014;76: 196–200. 14. Baux S, Mimoun M, Saade H, et al. Burns in the elderly. Burns 1989;15:239–40. 15. Joseph B, Pandit V, Zangbar B, et al. Validating trauma-specific frailty index for geriatric trauma patients: a prospective analysis. J Am Coll Surg 2014;219:10–17.e1. 16. Kim SW, Han HS, Jung HW, et al. Multidimensional frailty score for the prediction of postoperative mortality risk. JAMA Surg 2014;149:633–40. 17. Green P, Woglom AE, Genereux P, et al. The impact of frailty status on survival after transcatheter aortic valve replacement in older adults with severe aortic stenosis: a single-center experience. JACC Cardiovasc Interv 2012;5:974–81. 18. Dasgupta M, Rolfson DB, Stolee P, Borrie MJ, Speechley M. Frailty is associated with postoperative complications in older adults with medical problems. Arch Gerontol Geriatr 2009;48:78–83. 19. Mitnitski A, Song X, Skoog I, et al. Relative fitness and frailty of elderly men and women in developed countries and their relationship with mortality. J Am Geriatr Soc 2005;53:2184–9.
