30 years later—Does the ABSI need revision?

burns 37 (2011) 958–963

available at www.sciencedirect.com

journal homepage: www.elsevier.com/locate/burns

30 years later—Does the ABSI need revision? Natasha A. Forster a,*, Matthias Zingg a, Sarah R. Haile b, Walter Ku¨nzi a, Pietro Giovanoli a, Merlin Guggenheim a a b

Department of Plastic and Hand Surgery, University Hospital Zu¨rich, Ra¨mistrasse 100, CH-8091 Zu¨rich, Switzerland Division of Biostatistics, Institute for Social and Preventive Medicine, University of Zurich, Switzerland

article info

abstract

Article history:

In light of changes in patient demographics together with constant developments in burn

Accepted 18 March 2011

care, the predictive accuracy of the Abbreviated Burns Severity Index (ABSI) – first described in 1982 – for estimating the mortality of present day burns patients, may be questionable.

Keywords:

We reviewed the records of 2813 burns patients treated between January 1968 and

Burns

December 2008 in the intensive care unit at our institution, aiming to identify emerging

ABSI score

discrepancies between the estimated and calculated outcome, based on each of the ABSI

Burns survival elderly

variables and the total burn score. The predictive value of each of the defined ABSI variables was confirmed to be highly significant. Univariable and multivariable analysis revealed an exponential increase in odds ratio (OR) for mortality for patients older than 60 years and more than 30% TBSA burned and showed OR values over 10 times higher than other significant variables like inhalation injury. Nevertheless, the ABSI for the estimation of mortality in our entire patient collective was highly accurate and could not be optimised by adapting the point distribution to the increase in OR. Our data indicates that despite significant changes in patient demographics and medical advances over the past 30 years, the ABSI scoring system is still an accurate and valuable tool in the prediction of burn patient mortality. # 2011 Elsevier Ltd and ISBI. All rights reserved.

1.

Introduction

Since its first description in 1982, the Abbreviated Burn Severity Index (ABSI) has gained wide acceptance as a useful tool for predicting the mortality of burn victims (Table 1) [1,2]. Estimating the outcome, particularly of severely burned patients, has both a significant impact on medical decision making and is unfortunately also of socio-economic relevance. In recent years, significant developments in the treatment of burns victims have been made, ranging from improved monitoring, resuscitation and nutritional supplementation, to a more profound knowledge of efficient surgical wound management in conjunction with the use of synthetic and

bioengineered skin substitutes [3–6]. Nevertheless, the severely burned patient remains a multidisciplinary challenge, which starts with the difficult decision of whether or not to resuscitate the patient in the first instance. The pursuit of an ‘‘all-or-nothing principle’’, and subsequently refraining from initiating the extensive treatment machinery burns patients require, is highly controversial when the prognosis is dire. With the aid of a reliable and precise method for predicting a patient’s survival, the medical team and the patient’s family can be guided to make an educated decision about the extent of treatment that can and should be invested. Despite having prevailed over the years as a reliable and fairly simple scoring system, changes in patient demographics together with the afore mentioned advances in burn care, the

* Corresponding author. Tel.: +41 44 255 95 31. E-mail addresses: [email protected], [email protected] (N.A. Forster). 0305-4179/$36.00 # 2011 Elsevier Ltd and ISBI. All rights reserved. doi:10.1016/j.burns.2011.03.009

burns 37 (2011) 958–963

Table 1 – Abbreviated Burns Severity Index (ABSI) (1). The burn score is calculated by adding the number of points awarded for each variable, subsequently providing an estimate of the patient’s survival probability. Variable

Patient characteristic

Sex

Male Female 0–20 21–40 41–60 61–80 80–100

Age

Inhalation injury Full thickness burn TBSA burned (%)

Score 1 0 1 2 3 4 5 1 1 1 2 3 4 5 6 7 8 9 10

1–10 11–20 21–30 31–40 41–50 51–60 61–70 71–80 81–90 91–100

ABSI burn score

Threat to life

2–3 4–5 6–7 8–9 10–11 12–13

Very low Moderate Moderately severe Serious Severe Maximum

Probability of survival >99% 98% 80–90% 50–70% 20–40% <10%

TBSA: total body surface area.

accuracy of the ABSI in outcome prediction for the present day patient is questionable [7]. Especially the appropriateness of the weighting of the individual ABSI variables warrants reassessment. For this purpose, we reviewed the records of all burns patients treated over the past 41 years in the intensive care unit at our institution, aiming to identify emerging discrepancies between the estimated and calculated outcome, based on each of the ABSI score variables and the total index.

2.

Patients and methods

Data of patients treated at the Burns Intensive Care Unit (ICU) of the University Hospital Zurich, Switzerland, between January 1968 and December 2008 were collected and analysed retrospectively. The facility is one of only two specialist burns centres in Switzerland, comprising 6 intensive care beds, with an average turn-over of 75 patients per year. The study was approved by the institutional review board. Before 1998 the data were extracted from paper archives, whereas records from the following 10 years were obtained from the computed clinic information system (KISIM, 4.901) of the University Hospital Zurich. A total of 2813 patients who were treated in the burns intensive care unit during the 41 years were included in the study and were subdivided into five groups according to the time period in which they were hospitalised (block 1: 1968–1976, block 2: 1977–1984, block 3:

959

1985–1992, block 4: 1993–2000, block 5: 2001–2008). The patient data was stratified according to the ABSI score variables, including gender, age, inhalation injury, total body surface area (TBSA) burned, the presence of 3rd degree burns and also suicide, the outcome/survival and length of stay in the intensive care unit. Consistent with the ABSI scoring system, patients were grouped by age at 20-year intervals (group 1 0–20 years, group 2 21–40 years, etc.) and the burned TBSA at 10% intervals (group 1 1–10%, group 2 11–20%, group 3 21–30%, etc.). For multivariable analysis the baseline was defined as a male patient, age 0–20 years, with no inhalation trauma, no 3rd degree burns and less than 10% TBSA burned. Mathematical statistics were performed with the assistance of the Division of Biostatistics at the University of Zurich. Student’s two-tailed t-test was used to compare groups. Data was further analysed using logistic regression [8], revealing the odds ratio and the corresponding p value. A p value < 0.05 was considered significant. All data was analysed in R [9] and the logistic regression was calculated using the glm function [10].

3.

Results

The records of 2813 patients treated for burn injuries at the specialist burns intensive care unit of the University Hospital of Zu¨rich between 1968 and 2008 were included in the study. Male patients were more common than females (2058 (73.2%) versus 755 (26.8%), respectively) and males were significantly younger on average than their female counterparts (38.5 years, SD 16.9 versus 46.5, SD 21.6 years respectively, p = 0.002). Over one third of the injuries occurred within domestic confines (38% (1091/2831)). Other common causes were associated with the use of accelerants or oil (14%, 408/2813), industrial chemicals (12.4%, 353/2813), electricity (8.61%, 244/2813) and motor vehicle accidents (6.3%, 181/2813). Overall, the mortality rate was 18%. The highest rate (24%) was seen in the first observation period from 1968 to 1976, after which there were no significant differences between the numbers of fatalities ( p = 0.25) (Table 2). Suicide was a major cause of death amongst all evaluated patients, reaching a mortality rate of 42.9%. The injuries of these patients were extensive with an average burned TBSA of 45% (SD 28.5). Patients who survived were both significantly younger and had less extensive burns than those who died (38.1 years, SD 17.1 versus 49.3 years, SD 22.0 and 21.3% TBSA, SD 1.8 versus 52.6% TBSA, SD 4.4 for survivors and non-survivors respectively, p < 0.0001) (Fig. 1). The extent of the burn injuries did not vary significantly between the different time periods ( p = 0.996). In the low ABSI groups (total burn score < 5) a distinct male dominance was seen with a male to female ratio of 10:1, whereas the higher ABSI groups (total burn score > 5), especially amongst patients with a burn score >10, a more even sex distribution (male to female radio 3:2) was seen. The total length of stay (LOS) in the intensive care unit showed strong variation, ranging between 1 and 232 days. The median was 16 days, but survivors showed a significantly longer median LOS than non-survivors (20 days versus 8 days, respectively, p < 0.0001). Despite the possibly confounding high standard deviation values, the data suggest that patients who survived spent a longer time in the intensive care unit, in

960

burns 37 (2011) 958–963

Table 2 – Mean age of patients included in the study, stratified for the time period in which they were treated, survivors and fatalities and their length of stay. Period

Patients total

Survivors

Total

m

Age

Total

m

Age

1968–1976

503

378

650

487

1985–1992

572

417

1993–2000

529

374

2001–2008

559

402

1968–2008

2813

2058

382 (75%) 529 (81%) 514 (89%) 433 (81%) 465 (83%) 2323 (82%)

296

1977–1984

34.9 (17.21) 38.2 (18.33) 40.4 (18.4) 43.8 (18.62) 46.0 (20.13) 40.7 (18.57)

31.6 (14.5) 36.3 (16.79) 38.3 (16.69) 40.5 (16.44) 42.8 (16.85) 38.1 (17.13)

401 383 310 336 1726

Fatalities LOS

Total

m

Age

24

121 (25%) 121 (19%) 58 (11%) 96 (19%) 94 (17%) 490 (18%)

82

40.4 (20.49) 43.6 (21.82) 56.4 (22.13) 58.4 (21.19) 55.5 (21.23) 49.3 (21.96)

23 20 13 19 20

86 34 64 66 332

LOS 8 8 9.5 6 7 8

m, male; LOS, length of stay in days; Age given as mean  standard deviation, LOS given as median.

turn indicating that non-survivors tend to die early in the course of treatment (Table 2). Univariable analysis of the individual ABSI parameters, together with the total ABSI burn score and showed that, each of the variables had a significant influence on mortality. Sex was found to be the weakest predictive variable (OR 1.7, 95% CI

[()TD$FIG]

1.3–2.0, p < 0.00001), whilst the presence of inhalation injury and third degree burns trauma could be confirmed as having a significant impact on patient survival (OR 3.4, 95% CI 2.3–4.5 and OR 3.4, 95% CI 2.6–4.5, respectively, jp < 0.00001). Rather than looking at age and TBSA as single variables, the values were split into individual groups according to the ABSI scoring system. Somewhat unexpectedly, this revealed the odds ratios (OR) for age over 61 years to increase dramatically. A similar trend could also be seen for the TBSA, where the predictive values for mortality reached over 10 times that of any other ABSI variable (Table 3). Using multivariable analysis, with all other variables held constant, age between 61 and 80 and 81 and over were associated with a 15 and even 56 times higher odds of mortality than the 0–20 age group (Table 4). In order to evaluate whether the nearly exponential increase of the odds ratios for age and TBSA when analysed

Table 3 – Univariable analysis revealed that the total ABSI and each of its individual variables were significant predictors of mortality.

Fig. 1 – Patient outcome in relation to the time period treated, age (A) and percentage TBSA burned (B). Non survivors were both older and had significantly more extensive burn wounds ( p < 0.0001). There was no significant difference in average TBSA burned when comparing the different time periods ( p = 0.996).

ABSI burn score Female sex Age 0–20 years Age 21–40 years Age 41–60 years Age 61–80 years Age 81–100 years TBSA 1–10% TBSA 11–20% TBSA 21–30% TBSA 31–40% TBSA 41–50% TBSA 51–60% TBSA 61–70% TBSA 71–80% TBSA 81–90% TBSA 91–100% 38-Burns Inhalation injury

Odds ratio

95% CI

p-Value

4.2 1.7 1.00 1.3 2.1 6.0 14.1 1.00 2.9 5.7 10.3 13.2 27.7 48.5 51.6 371.3 223.2 3.4 3.4

3.7–4.7 1.3–2.0

<0.00001 <0.00001

0.8–2.0 1.4–3.3 4.0–9.6 8.5–24.6

0.2697 0.0011 <0.00001 <0.00001

1.8–4.5 3.7–9.0 6.7–16.2 8.3–21.1 17.0–45.8 28.7–84.0 28.0–97.9 141.9–1280.7 73.4–974.1 2.6–4.5 2.3–4.5

<0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001

CI: 95% confidence intervals.

961

burns 37 (2011) 958–963

Table 4 – Multivariable analysis, with the baseline defined as a male patient, age 0–20 years, with no inhalation trauma, no 3rd degree burns and less than 10% TBSA burned, demonstrated a dramatic increase in odds for patients over 60 years and with extensive burns over 30% TBSA.

Female sex Age 0–20 years Age 21–40 years Age 41–60 years Age 61–80 years Age 81–100 years TBSA 1–10% TBSA 11–20% TBSA 21–30% TBSA 31–40% TBSA 41–50% TBSA 51–60% TBSA 61–70% TBSA 71–80% TBSA 81–90% TBSA 91–100% 38-Burns Inhalation injury

Odds ratio

95% CI

p-Value

1.4 1.00 1.1 2.5 14.8 56.0 1.00 2.5 8.4 16.2 26.9 60.0 128.5 155.7 1001.6 638.8 1.5 2.6

1.1–2.0

<0.00001

0.6–1.8 1.5–4.4 48.4–27.0 28.6–112.9

0.2697 0.0011 <0.00001 <0.00001

1.5–4.1 5.0–14.3 9.7–27.7 15.5–47.5 33.5–109.7 69.5–244.9 77.2–322.7 357.9–3612.6 195.3–2913.1 1.0–2.1 15.0–4.3

<0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001 <0.00001

CI: 95% confidence intervals.

per score interval had an impact on the accuracy of the predictive value of the score, the actual mortality and the predicted mortality according to the ABSI were compared. Furthermore a modified ABSI score was also tested in an attempt to reflect the steeper increase in OR with age over 60. As shown in Table 5, both the calculated mortality rates based on our data using the original and modified ABSI score were well within the range of the mortality estimate defined by the ABSI.

4.

Discussion

In the age of tissue engineering, state of the art synthetic and biological wound dressings, high-tech monitoring devices and a rapidly increasing knowledge of cellular and molecular mechanisms behind local and systemic reactions to injury, the treatment of the severely burned patient still remains a challenge sometimes insurmountable. The ABSI was first proposed in 1982 as a scoring system to predict the outcome of burns victims and thereby facilitate or guide treatment decisions [1]. With the growing pressure of financial restrictions, predictive scoring systems can assume a pivotal role in objectifying where to limit therapeutic efforts, making it imperative that its variables and their weighting are evidence based.

Table 5 – The calculated mortality rates based on our data with the original and modified ABSI score (A) were both well within the range of the mortality estimate defined by the ABSI. Variable

Patient characteristic

(A) Sex

Modified ABSI

1 0 1 2 3 4 5 1 1 1 2 3 4 5 6 7 8 9 10

1 0 0 0 1 2 5 1 1 1 2 3 4 5 6 7 8 9 10

Male Female 0–20 21–40 41–60 61–80 80–100

Age

Inhalation injury Full thickness burn TBSA burned (%)

1–10 11–20 21–30 31–40 41–50 51–60 61–70 71–80 81–90 91–100

ABSI burn score

(B) 2–3 4–5 6–7 8–9 10–11 12–13

Original ABSI

Original ABSI

Modified ABSI

Estimated mortality

Patients n=

Actual mortality

Patients n=

Actual mortality

<1% 2% 10–20% 30–50% 60–80% >90%

200 850 809 498 265 191

0.4% 1.9% 7.7% 26.8% 61.5% 87.4%

1020 780 502 293 156 62

0.98% 5.76% 23.10% 48.80% 85.89% 91.93%

962

burns 37 (2011) 958–963

Reviewing the data of our 2813 burns patients we found an overall mortality rate 18%, which is comparable to numbers found in the literature [11]. Interestingly we were not able to demonstrate the expected impact of technological advancements on survival rate over the years, whereby the survival rate in our cohort did increase, but not to a statistically significant degree. This coincides with a number of retrospective studies from the 1990, demonstrating a distinct decrease in overall mortality of burns victims until the mid 1980s, after which the downwards trend seemed to stagnate [12–18]. In contrast, in a retrospective review over 30 years Lionelli et al. showed that the mortality rates of elderly burns victims showed a significant and also progressive decrease over the entire observation period [19]. In our patient collective, each of the ABSI variables was found to be a significant predictor of mortality. The odds ratio (OR) for the mortality of patients aged 61–80 and 81–100 years was dramatically higher than any of the other individual variables, such as inhalation injury or third degree burns. Moreover, whereas the calculated OR for TBSA overall was only 1.9 (95%CI 1.8–2.0), analysing the TBSA values split into the intervals according to the ABSI, a similar trend was noted. This contradicts previous reports indicating that inhalation injury is one of the most powerful predictors of mortality [7,20–23]. The seemingly exponential increase in odds for mortality with growing age and burned TBSA could lead to the conclusion that assigning points to increasing TBSA and age in a linear manner, as it is currently defined by the ABSI, may cause the mortality of patients with extensive burns and/or age over 60 years to be underestimated. However when comparing the estimated mortality of the patients according to the ABSI with the calculated mortality of our patient collective, we found the ABSI score still to be sufficiently accurate. Furthermore by modifying the scores given for the age groups in an attempt to better reflect the increase in odds for mortality beyond the age of 60 years, no significant improvement of the accuracy of the score could be achieved (Table 5). As other authors have pointed out, therapeutic decisions based on rigid adherence to scoring systems, especially when coerced by socio-economic incentives, can be ethically questionable and even dangerously inaccurate [7,33]. Nevertheless, when used appropriately, scoring systems such as the ABSI can not only aid medical decision making, but also serve to encourage both staff and relatives in the often arduous treatment course of burns victims. Elderly burns victims represent a unique patient group, not only due to their more prevalent co-morbidities, but also their altered and often more extreme physiological responses to stress. Multiple studies investigating the treatment and outcome of these patients have shown that they tend to do significantly worse than their younger counterparts with similar injury profiles [19,24–32]. However, rigid interpretation of this data has the potential of leading to undue discouragement in treating the elderly. Alongside the advances in care and medical resources, the demographics of our population have changed dramatically over the past few decades, whereby the population aged over 65 years is estimated to grow to nearly 20% by 2025 [United Nations, Population Division, World Population Prospects 2008 Revision, http://

esa.un.org/UNPP/p2k0data.asp]. As a consequence, the physiological state of an average 60 year-old today cannot be compared to a similarly aged patient 40 years ago. Accordingly, our patient collective not only showed a steady increase in its overall mean age and age range, but also the mean age of the fatalities became higher. It is therefore imperative that standardised treatment protocols be adjusted to accommodate the current day patient. The ABSI scoring system was conceived in 1982, based on a data set of 590 patients from two burn centres. Using our extensive database of close to 3000 burns patients treated at our unit, we sought to substantiate the assumption that the afore mentioned changes in patient demographics and advances in medical care might call for modifications to the ABSI. Based on our analysis however we must concede that 30 years later, the ABSI scoring system is still an accurate and useful tool for the prediction of mortality in burns patients.

Conflict of interest None.

references

[1] Tobiasen J, Hiebert JM, Edlich RF. The abbreviated burn severity index. Ann Emerg Med 1982;11:260–2. [2] Horbrand F, Schrank C, Henckel-Donnersmarck G, Muhlbauer W. Integration of preexisting diseases and risk factors in the Abbreviated Burn Severity Index (ABSI). Anasthesiol Intensivmed Notfallmed Schmerzther 2003;38:151–7. [3] Pruitt Jr BA, Wolf SE. An historical perspective on advances in burn care over the past 100 years. Clin Plast Surg 2009;36:527–45. [4] Sheridan R. Closure of the excised burn wound: autografts, semipermanent skin substitutes, and permanent skin substitutes. Clin Plast Surg 2009;36:643–51. [5] Latenser BA. Critical care of the burn patient: the first 48 hours. Crit Care Med 2009;37:2819–26. [6] Alvarado R, Chung KK, Cancio LC, Wolf SE. Burn resuscitation. Burns 2009;35:4–14. [7] Germann G, Barthold U, Lefering R, Raff T, Hartmann B. The impact of risk factors and pre-existing conditions on the mortality of burn patients and the precision of predictive admission-scoring systems. Burns 1997;23:195–203. [8] Hosmer DW, Lemeshow S. Applied Logistic Regression: Wiley Series in Probability and Statistics. New York, NY: John Wiley & Sons; 2000. [9] R Development Core Team. R: A Language and Environment for Statistical Computing. Vienna, Austria: R Roundation for Statistical Computing; 2009, ISBN 3-900051-07-0. [10] Reporttools RK. R functions to generate latex tables of descriptive statistics. J stat soft 2009;31:1–7. [11] Brusselaers N, Monstrey S, Vogelaers D, Hoste E, Blot S. Severe burn injury in Europe: a systematic review of the incidence, aetiology, morbidity and mortality. Crit Care 2010;14:R188. [12] Muller MJ, Herndon DN. The challenge of burns. Lancet 1994;343:216–20. [13] Curreri PW, Luterman A, Braun Jr DW, Shires GT. Burn injury. Analysis of survival and hospitalization time for 937 patients. Ann Surg 1980;192:472–8.

burns 37 (2011) 958–963

[14] Herruzo-Cabrera R, Fernandez-Arjona M, Garcia-Torres V, Martinez-Ratero S, Lenguas-Portero F, Rey-Calero J. Mortality evolution study of burn patients in a critical care burn unit between 1971 and 1991. Burns 1995;21:106–9. [15] McGwin Jr G, Cross JM, Ford JW, Rue III LW. Long-term trends in mortality according to age among adult burn patients. J Burn Care Rehabil 2003;24:21–5. [16] Brusselaers N, Hoste EA, Monstrey S, Colpaert KE, De Waele JJ, Vandewoude KH, et al. Outcome and changes over time in survival following severe burns from 1985 to 2004. Intensive Care Med 2005;31: 1648–53. [17] Pereira CT, Barrow RE, Sterns AM, Hawkins HK, Kimbrough CW, Jeschke MG, et al. Age-dependent differences in survival after severe burns: a unicentric review of 1,674 patients and 179 autopsies over 15 years. J Am Coll Surg 2006;202:536–48. [18] Wibbenmeyer LA, Amelon MJ, Morgan LJ, Robinson BK, Chang PX, Lewis II R, et al. Predicting survival in an elderly burn patient population. Burns 2001;27:583–90. [19] Lionelli GT, Pickus EJ, Beckum OK, Decoursey RL, Korentager RA. A three decade analysis of factors affecting burn mortality in the elderly. Burns 2005;31: 958–63. [20] Shirani KZ, Pruitt Jr BA, Mason Jr AD. The influence of inhalation injury and pneumonia on burn mortality. Ann Surg 1987;205:82–7. [21] Hassan Z, Wong JK, Bush J, Bayat A, Dunn KW. Assessing the severity of inhalation injuries in adults. Burns 2010;36:212–6. [22] Wang Y, Tang HT, Xia ZF, Zhu SH, Ma B, Wei W, et al. Factors affecting survival in adult patients with massive burns. Burns 2010;36:57–64.

963

[23] Ryan CM, Schoenfeld DA, Thorpe WP, Sheridan RL, Cassem EH, Tompkins RG. Objective estimates of the probability of death from burn injuries. N Engl J Med 1998;338:362–6. [24] Mahar P, Wasiak J, Bailey M, Cleland H. Clinical factors affecting mortality in elderly burn patients admitted to a burns service. Burns 2008;34:629–36. [25] McGill V, Kowal-Vern A, Gamelli RL. Outcome for older burn patients. Arch Surg 2000;135:320–5. [26] Burton KR, Sharma VK, Harrop R, Lindsay R. A populationbased study of the epidemiology of acute adult burn injuries in the Calgary Health Region and factors associated with mortality and hospital length of stay from 1995 to 2004. Burns 2009;35:572–9. [27] Covington DS, Wainwright DJ, Parks DH. Prognostic indicators in the elderly patient with burns. J Burn Care Rehabil 1996;17:222–30. [28] Andel D, Kamolz LP, Niedermayr M, Hoerauf K, Schramm W, Andel H. Which of the abbreviated burn severity index variables are having impact on the hospital length of stay? J Burn Care Res 2007;28:163–6. [29] Rao K, Ali SN, Moiemen NS. Aetiology and outcome of burns in the elderly. Burns 2006;32:802–5. [30] Pomahac B, Matros E, Semel M, Chan RK, Rogers SO, Demling R, et al. Predictors of survival and length of stay in burn patients older than 80 years of age: does age really matter? J Burn Care Res 2006;27:265–9. [31] Keck M, Lumenta DB, Andel H, Kamolz LP, Frey M. Burn treatment in the elderly. Burns 2009;35:1071–9. [32] Lumenta DB, Hautier A, Desouches C, Gouvernet J, Giorgi R, Manelli JC, et al. Mortality and morbidity among elderly people with burns—evaluation of data on admission. Burns 2008;34:965–74. [33] Choiniere M, Dumont M, Papillon J, Garrel DR. Prediction of death in patients with burns. Lancet 1999;353:2211–2.