The measured effect magnitude of co-morbidities on burn injury mortality

Abstract

Introduction The ability to better prognosticate burn injury outcome is challenging and historically, most center use the Baux or revised Baux score to help prognosticate burn outcome, however, the weighted contribution of comorbidity on burn mortality has traditionally not been accounted for nor adequately studied. We therefore sought to determine the effect of comorbidities, using the Charlson comorbidity index (CCI) on burn mortality. Methods The purpose of this study was to determine the effect of comorbidities on burn injury mortality as determined by the LA50 (lethal TBSA burn at which 50% of the cohort will succumb from the burn injury) in a retrospective analysis of patients admitted to a regional burn center from 2002–2012. Independent variables analyzed included basic demographics, burn mechanism, presence of inhalation injury, TBSA (total body surface area), length of hospital stay, and pre-existing comorbidities. Bivariate analysis was performed and logistic regression modeling using significant variables was utilized to estimate odds of death. Results 7640 patients were included in this study. Overall survival rate was 96%. 40% of our burn cohort had at least one comorbidity. There was a linear increase in the likelihood of death with an increase in CCI. The logistic regression model for mortality outcomes identified four statistically significant variables: age, TBSA, inhalational injury and the presence of comorbidities (OR = 1.59 for each 1 point increase in CCI; 95% CI 1.44–1.77). The unadjusted LA50 was 53% for the entire cohort. Partial adjustment multivariate regression controlling for burn mechanism and inhalation injury only, produced a slight reduction in LA50 for the 0–18 and 19–64 age categories to 76% and 48%, respectively, but a significant decrease occurred in the ≥ 65 years age group with a reduced LA50 to 20% (p<0.001). After full adjustment for all significant covariates, including comorbidities, the independent magnitude of effect of comorbidities on the LA50 was evident in the <65 cohort. The full adjustment showed a LA50 decreased by 15 and 5%, respectively in the 0–18 and >18–65 age groups respectively (p<0.001), however, in the >65 years age cohort there was no change in the LA50. Conclusion Preexisting comorbidities have a significant effect on burn injury mortality in all age groups, particularly the younger burn population. The measured effect of comorbidities in the >65yr age cohort was mitigated by the co-linearity between age and comorbidities. The inclusion of CCI is imperative so as to better prognosticate burn outcome and help guide expectations and resource utilization, particularly in the younger burn cohort..

Amputation Following Burn Injury

“…Comorbidities have been previously shown to play an important role in patient outcomes following burn injury. 25,26 We demonstrated that for every point increase in CCI score, the odds of amputation increased 29%. Additionally, we noted that those patients who underwent both major and minor amputation procedures had a higher median CCI than those who underwent either one alone.…”

Multi-institutional analysis of independent predictors for burn mortality in the United States

“…Pompermaier et al also argued that comorbidities play an inferior role in comparison to age in burn mortality models [ 19 ]. On the other hand, Knowlin et al demonstrated in a single-center study that comorbidities are in fact associated with increased mortality after burns [ 20 ]. In our outcome analysis, other clinical factors were more predominant.…”

Outcome of burn care : the mortality perspective

“…50 On the other hand, recent studies have shown that pre-existing disorders do have an impact on mortality, particularly among younger patients. 87,88 However, severe conditions such as HIV/ AIDS, metastatic cancer, and renal and liver diseases raised the odds in favour of death, and the risk of mortality increased with the number of disorders.…”