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

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. 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 to 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. 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% TBSA, respectively, but a significant decrease occurred in the ≥65 years age group with a reduced LA50 to 20% TBSA (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 to 61% and 43% TBSA, 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. 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 >65 yr 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.

Knowlin L ，Stanford L ，Moore D ，Cairns B ，Charles A ... -  《-》

Long term mortality in critically ill burn survivors.

Little is known about long term survival risk factors in critically ill burn patients who survive hospitalization. We hypothesized that patients with major burns who survive hospitalization would have favorable long term outcomes. We performed a two center observational cohort study in 365 critically ill adult burn patients who survived to hospital discharge. The exposure of interest was major burn defined a priori as >20% total body surface area burned [TBSA]. The modified Baux score was determined by age + %TBSA+ 17(inhalational injury). The primary outcome was all-cause 5year mortality based on the US Social Security Administration Death Master File. Adjusted associations were estimated through fitting of multivariable logistic regression models. Our final model included adjustment for inhalational injury, presence of 3rd degree burn, gender and the acute organ failure score, a validated ICU risk-prediction score derived from age, ethnicity, surgery vs. medical patient type, comorbidity, sepsis and acute organ failure covariates. Time-to-event analysis was performed using Cox proportional hazard regression. Of the cohort patients studied, 76% were male, 29% were non white, 14% were over 65, 32% had TBSA >20%, and 45% had inhalational injury. The mean age was 45, 92% had 2nd degree burns, 60% had 3rd degree burns, 21% received vasopressors, and 26% had sepsis. The mean TBSA was 20.1%. The mean modified Baux score was 72.8. Post hospital discharge 5year mortality rate was 9.0%. The 30day hospital readmission rate was 4%. Patients with major burns were significantly younger (41 vs. 47 years) had a significantly higher modified Baux score (89 vs. 62), and had significantly higher comorbidity, acute organ failure, inhalational injury and sepsis (all P<0.05). There were no differences in gender and the acute organ failure score between major and non-major burns. In the multivariable logistic regression model, major burn was associated with a 3 fold decreased odds of 5year post-discharge mortality compared to patients with TBSA<20% [OR=0.29 (95%CI 0.11-0.78; P=0.014)]. The adjusted model showed good discrimination [AUC 0.81 (95%CI 0.74-0.89)] and calibration (Hosmer-Lemeshow χ2 P=0.67). Cox proportional hazard multivariable regression modeling, adjusting for inhalational injury, presence of 3rd degree burn, gender and the acute organ failure score, showed that major burn was predictive of lower mortality following hospital admission [HR=0.34 (95% CI 0.15-0.76; P=0.009)]. The modified Baux score was not predictive for mortality following hospital discharge [OR 5year post-discharge mortality=1.00 (95%CI 0.99-1.02; P=0.74); HR for post-discharge mortality=1.00 (95% CI 0.99-1.02; P=0.55)]. Critically ill patients with major burns who survive to hospital discharge have decreased 5year mortality compared to those with less severe burns. ICU Burn unit patients who survive to hospital discharge are younger with less comorbidities. The observed relationship is likely due to the relatively higher physiological reserve present in those who survive a Burn ICU course which may provide for a survival advantage during recovery after major burn.

Nitzschke S ，Offodile AC 2nd ，Cauley RP ，Frankel JE ，Beam A ，Elias KM ，Gibbons FK ，Salim A ，Christopher KB ... -  《-》

The effect of smoking status on burn inhalation injury mortality.

Three factors that effect burn mortality are age, total body surface of burn (TBSA), and inhalation injury. Of the three, inhalation injury is the strongest predictor of mortality thus its inclusion in the revised Baux score (age+TBSA+17* (inhalation injury, 1=yes, 0=no)). However, the weighted contribution of specific comorbidities such as smoker status on mortality has traditionally not been accounted for nor studied in this subset of burn patients. We therefore sought to examine the impact of current tobacco and/or marijuana smoking in patients with inhalation injury. A retrospective analysis of patients admitted to a regional burn center from 2002 to 2012. Independent variables analyzed included basic demographics, burn mechanism, presence of inhalation injury, TBSA, pre-existing comorbidities, and smoker status. Bivariate analysis was performed and logistic regression modeling using significant variables was utilized to estimate odds of mortality. There were a total of 7640 patients over the study period. 7% (n=580) of the burn cohort with inhalation injury were included in this study. In-hospital burn mortality for inhalation injury patients was 23%. Current smokers (20%) included cigarette smokers and marijuana users, 19% and 3%, respectively. Preexisting respiratory disease (17%) was present in 36% of smokers compared to 13% of non-smokers (p<0.001). Smokers had significantly lower mortality rate (9%) compared to non-smokers (26%, p<0.01). The logistic regression model for mortality outcomes identified statistically four significant variables: age, TBSA, ethnicity, and smoker status (OR=0.41, 95% CI=0.18-0.93). Presence of comorbidities, including preexisting respiratory disease, was not significant. In the sub group of burn patients with inhalation injury, the odds of mortality significantly decreased in pre-existing smokers after adjusting for significant covariates. We postulate that an immune tolerance mechanism that modulates and diminishes the pro-inflammatory response confers a survival advantage in smokers after exposure to acute smoke inhalation injury. Future prospective studies in human and/or animal models are needed to confirm these findings.

Knowlin L ，Stanford L ，Cairns B ，Charles A ... -  《-》

Revised Baux Score and updated Charlson comorbidity index are independently associated with mortality in burns intensive care patients.

The purpose of the current study was to utilise established scoring systems to analyse the association of (i) burn injury severity, (ii) comorbid status and (iii) associated systemic physiological disturbance with inpatient mortality in patients with severe burn injuries admitted to intensive care. Case notes of all patients with acute thermal injuries affecting ≥15% total body surface area (TBSA) admitted to the Burns Intensive Care Unit (BICU) at Chelsea and Westminster Hospital during a 10-year period were retrospectively reviewed. Revised Baux Score, Belgian Outcome in Burn Injury (BOBI) Score, Abbreviated Burn Severity Index (ABSI), APACHE II Score, Sequential Organ Failure Assessment (SOFA) Score and Updated Charlson Comorbidity Index (CCI) were computed for each patient and analysed for association with inpatient mortality. Ninety mechanically ventilated patients (median age 45.7 years, median % TBSA burned 36.5%) were included. 72 patients had full thickness burns and 35 patients had inhalational injuries. Forty-four patients died in hospital while 46 survived to discharge. In a multivariate logistic regression model, only the Revised Baux Score (p<0.001) and updated CCI (p=0.014) were independently associated with mortality. This gave a ROC curve with area under the curve of 0.920. On multivariate cox regression survival analysis, only the Revised Baux Score (p<0.001) and the updated CCI (p=0.004) were independently associated with shorter time to death. Our data suggest that the Revised Baux Score and the updated CCI are independently associated with inpatient mortality in patients admitted to intensive care with burn injuries affecting ≥15% TBSA. This emphasises the importance of comorbidities in the prognosis of patients with severe burn injuries.

Heng JS ，Clancy O ，Atkins J ，Leon-Villapalos J ，Williams AJ ，Keays R ，Hayes M ，Takata M ，Jones I ，Vizcaychipi MP ... -  《-》

Determination of risk factors for burn mortality based on a regional population study in Taiwan.

Burns are not only major personal catastrophic events but also constitute a national health problem due to its associated morbidity, rehabilitation, mortality and high cost medical services. Advances in care and treatment have increased survival from major burn injury. However, information on the epidemiology and risk factors of burn mortality in Taiwan is limited. The study aim was to determine the nationwide epidemiological characteristics, trends, and mortality risk factors of burn inpatients in Taiwan. This nationwide population-based study evaluated data retrieved from the Taiwan National Health Insurance database. Patients hospitalized for burns (ICD-9-CM codes 940-949) between 2003 and 2013 were identified from hospitalization records. A total of 73,774 patients were included. The data showed increases in age, revised Baux score, and Charlson Comorbidity Index during the study period, but it was also accompanied by a continuing decrease in burn incidence and a significant shortening of the length of hospital stay. The average in-hospital mortality was 17.5/1000 in 2003 and 12.2/1000 in 2013 but did not showed significant change. Male gender, older age, higher Charlson Comorbidity Index, presence of inhalation injury, large total burn surface area (TBSA), and higher revised Baux score were significant predictors of mortality. Population-based burn epidemiology data demonstrated ongoing improvement in hospital care during the past decade. Male gender, older age, higher Charlson Comorbidity Index, presence of inhalation injury, large TBSA, and higher revised Baux score were significant predictors of mortality.

Yen CI ，Chiou MJ ，Kuo CF ，Liao HT ... -  《-》