Research Original Investigation
Competing Risk Analysis in Patients With Burns
24. Scheike TH, Zhang M-J. Analyzing competing risk data using the R timereg package. J Stat Softw. 2011;38(2):1-15 2012. 25. Hess K, Gentleman R. muhaz: hazard function estimation in survival analysis. R package version 1.2.5. 2010. 26. McGwin G Jr, George RL, Cross JM, Rue LW. Improving the ability to predict mortality among burn patients. Burns. 2008;34(3):320-327.
27. Osler T, Glance LG, Hosmer DW. Simplified estimates of the probability of death after burn injuries: extending and updating the Baux score. J Trauma. 2010;68(3):690-697. 28. Smith DL, Cairns BA, Ramadan F, et al. Effect of inhalation injury, burn size, and age on mortality: a study of 1447 consecutive burn patients. J Trauma. 1994;37(4):655-659.
29. Miller SF, Finley RK, Waltman M, Lincks J. Burn size estimate reliability: a study. J Burn Care Rehabil. 1991;12(6):546-559. 30. Wachtel TL, Berry CC, Wachtel EE, Frank HA. The inter-rater reliability of estimating the size of burns from various burn area chart drawings. Burns. 2000;26(2):156-170.
Invited Commentary
Competing Risks and Burn Outcomes More Questions Than Answers Amalia Cochran, MD; Iris H. Faraklas, RN, BSN
Age, total body surface area of burn injury, and inhalation injury have long been documented as independent predictors of mortality in burn injury1; all these factors are identifiable on admission. In this issue, Taylor et al2 propose the use Related article page 450 of competing risk analysis to examine dynamic factors that may affect length of stay and mortality in patients with burns. Although this method is new in patients with burns, it was initially applied in a large cohort of patients with trauma more than a decade ago.3 Modeling outcomes in patients with complex conditions, such as burns and trauma, is inherently fraught with challenges. The key assumption underlying the use of competing risk analysis is that the causes of early and late mortality are different in patients with burns as they are in patients with trauma.4 The authors include a single paragraph with a simple univariate description of patients who died within 1 day of ARTICLE INFORMATION
Conflict of Interest Disclosures: None reported.
Author Affiliations: Department of Surgery, University of Utah, Salt Lake City; University of Utah Burn Center, Salt Lake City.
REFERENCES
Corresponding Author: Amalia Cochran, MD, Department of Surgery, University of Utah, 30 N 1900 East, SOM 3B110, Salt Lake City, UT 84132 ([email protected]). Published Online: March 11, 2015. doi:10.1001/jamasurg.2014.3512.
456
admission. Does this description provide a complete picture of patients who have early deaths following burn injury, or is the picture more complicated than the total body surface area of larger burn injuries and greater incidence of inhalation injury? Could depth of burns also play a role? Presumably, the 24-hour cutoff is designed to capture patients placed onto palliative care early; while National Burn Repository data do not include this information, do patients for whom the decision to start palliative care is later look more similar to patients who die early, or more similar to patients who die later? A trend analysis highlighting practice changes through the years could be developed using the included 9 years of data and would allow us to answer the exceptionally important question—are we getting better at the care of patients with burns? The use of competing risk analysis marks an important new way for us to consider outcomes in patients with burns. Ultimately, however, this analysis results in as many—or more— questions than answers.
1. Smith DL, Cairns BA, Ramadan F, et al. Effect of inhalation injury, burn size, and age on mortality: a study of 1447 consecutive burn patients. J Trauma. 1994;37(4):655-659. 2. Taylor SL, Sen S, Greenhalgh DG, et al. A competing risk analysis for hospital length of stay in patients with burns [published online March 11, 2015]. JAMA Surg. doi:10.1001/jamasurg.2014.3490.
3. Clark DE, Ryan LM. Concurrent prediction of hospital mortality and length of stay from risk factors on admission. Health Serv Res. 2002;37(3): 631-645. 4. Mullins RJ, Mann NC, Brand DM, Lenfesty BS. Specifications for calculation of risk-adjusted odds of death using trauma registry data. Am J Surg. 1997;173(5):422-425.
JAMA Surgery May 2015 Volume 150, Number 5 (Reprinted)
Copyright 2015 American Medical Association. All rights reserved.
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Competing Risk Analysis in Patients With Burns
24. Scheike TH, Zhang M-J. Analyzing competing risk data using the R timereg package. J Stat Softw. 2011;38(2):1-15 2012. 25. Hess K, Gentleman R. muhaz: hazard function estimation in survival analysis. R package version 1.2.5. 2010. 26. McGwin G Jr, George RL, Cross JM, Rue LW. Improving the ability to predict mortality among burn patients. Burns. 2008;34(3):320-327.
27. Osler T, Glance LG, Hosmer DW. Simplified estimates of the probability of death after burn injuries: extending and updating the Baux score. J Trauma. 2010;68(3):690-697. 28. Smith DL, Cairns BA, Ramadan F, et al. Effect of inhalation injury, burn size, and age on mortality: a study of 1447 consecutive burn patients. J Trauma. 1994;37(4):655-659.
29. Miller SF, Finley RK, Waltman M, Lincks J. Burn size estimate reliability: a study. J Burn Care Rehabil. 1991;12(6):546-559. 30. Wachtel TL, Berry CC, Wachtel EE, Frank HA. The inter-rater reliability of estimating the size of burns from various burn area chart drawings. Burns. 2000;26(2):156-170.
Invited Commentary
Competing Risks and Burn Outcomes More Questions Than Answers Amalia Cochran, MD; Iris H. Faraklas, RN, BSN
Age, total body surface area of burn injury, and inhalation injury have long been documented as independent predictors of mortality in burn injury1; all these factors are identifiable on admission. In this issue, Taylor et al2 propose the use Related article page 450 of competing risk analysis to examine dynamic factors that may affect length of stay and mortality in patients with burns. Although this method is new in patients with burns, it was initially applied in a large cohort of patients with trauma more than a decade ago.3 Modeling outcomes in patients with complex conditions, such as burns and trauma, is inherently fraught with challenges. The key assumption underlying the use of competing risk analysis is that the causes of early and late mortality are different in patients with burns as they are in patients with trauma.4 The authors include a single paragraph with a simple univariate description of patients who died within 1 day of ARTICLE INFORMATION
Conflict of Interest Disclosures: None reported.
Author Affiliations: Department of Surgery, University of Utah, Salt Lake City; University of Utah Burn Center, Salt Lake City.
REFERENCES
Corresponding Author: Amalia Cochran, MD, Department of Surgery, University of Utah, 30 N 1900 East, SOM 3B110, Salt Lake City, UT 84132 ([email protected]). Published Online: March 11, 2015. doi:10.1001/jamasurg.2014.3512.
456
admission. Does this description provide a complete picture of patients who have early deaths following burn injury, or is the picture more complicated than the total body surface area of larger burn injuries and greater incidence of inhalation injury? Could depth of burns also play a role? Presumably, the 24-hour cutoff is designed to capture patients placed onto palliative care early; while National Burn Repository data do not include this information, do patients for whom the decision to start palliative care is later look more similar to patients who die early, or more similar to patients who die later? A trend analysis highlighting practice changes through the years could be developed using the included 9 years of data and would allow us to answer the exceptionally important question—are we getting better at the care of patients with burns? The use of competing risk analysis marks an important new way for us to consider outcomes in patients with burns. Ultimately, however, this analysis results in as many—or more— questions than answers.
1. Smith DL, Cairns BA, Ramadan F, et al. Effect of inhalation injury, burn size, and age on mortality: a study of 1447 consecutive burn patients. J Trauma. 1994;37(4):655-659. 2. Taylor SL, Sen S, Greenhalgh DG, et al. A competing risk analysis for hospital length of stay in patients with burns [published online March 11, 2015]. JAMA Surg. doi:10.1001/jamasurg.2014.3490.
3. Clark DE, Ryan LM. Concurrent prediction of hospital mortality and length of stay from risk factors on admission. Health Serv Res. 2002;37(3): 631-645. 4. Mullins RJ, Mann NC, Brand DM, Lenfesty BS. Specifications for calculation of risk-adjusted odds of death using trauma registry data. Am J Surg. 1997;173(5):422-425.
JAMA Surgery May 2015 Volume 150, Number 5 (Reprinted)
Copyright 2015 American Medical Association. All rights reserved.
Downloaded From: http://archsurg.jamanetwork.com/ by a The University of Melbourne Libraries User on 01/17/2016
jamasurgery.com
