Knowlin Laquanda, Stanford Lindsay, Moore Danier, Cairns Bruce, Charles Anthony
Department of Surgery, University of North Carolina at Chapel Hill, North Carolina Jaycee Burn Center, United States.
Department of Surgery, University of North Carolina at Chapel Hill, North Carolina Jaycee Burn Center, United States.
Burns. 2016 Nov;42(7):1433-1438. doi: 10.1016/j.burns.2016.03.007. Epub 2016 Sep 1.
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.
更好地预测烧伤损伤结果具有挑战性，从历史上看，大多数中心使用博克斯（Baux）或修订后的博克斯评分来帮助预测烧伤结果，然而，合并症对烧伤死亡率的加权贡献传统上未被考虑，也未得到充分研究。因此，我们试图使用查尔森合并症指数（CCI）来确定合并症对烧伤死亡率的影响。
本研究的目的是通过对2002年至2012年入住某地区烧伤中心的患者进行回顾性分析，确定合并症对烧伤损伤死亡率的影响，该影响由LA50（半数队列将死于烧伤损伤的致死性烧伤总面积）来衡量。分析的自变量包括基本人口统计学特征、烧伤机制、吸入性损伤的存在、烧伤总面积（TBSA）、住院时间以及既往合并症。进行了双变量分析，并使用显著变量进行逻辑回归建模以估计死亡几率。
本研究纳入了7640例患者。总体生存率为96%。我们的烧伤队列中有40%至少有一种合并症。随着CCI的增加，死亡可能性呈线性增加。死亡率结果的逻辑回归模型确定了四个具有统计学意义的变量：年龄、烧伤总面积、吸入性损伤和合并症的存在（CCI每增加1分，比值比=1.59；95%置信区间1.44 - 1.77）。整个队列未调整的LA50为53%。仅对烧伤机制和吸入性损伤进行部分调整的多变量回归，使0 - 18岁和19 - 64岁年龄组的LA50略有降低，分别降至76%和48%的烧伤总面积，但≥65岁年龄组显著下降，LA50降至20%的烧伤总面积（p<0.001）。在对所有显著协变量（包括合并症）进行完全调整后，合并症对LA50的独立影响程度在<65岁队列中明显。完全调整显示，0 - 18岁和>18 - 65岁年龄组的LA50分别降至61%和43%的烧伤总面积（p<0.001），然而，在>65岁年龄队列中，LA50没有变化。
既往合并症对所有年龄组的烧伤损伤死亡率都有显著影响，尤其是年轻烧伤人群。在>65岁年龄队列中，合并症的测量效应因年龄和合并症之间的共线性而减弱。纳入CCI对于更好地预测烧伤结果以及帮助指导预期和资源利用至关重要，特别是在年轻烧伤队列中。
