Predictive value of quick SOFA and revised Baux scores in burn patients

Abstract

Several scoring systems, such as the Baux score, help predict outcomes in burn patients. The quick Sequential Organ Failure Assessment (qSOFA) score (composed of a respiratory rate of 22/min or greater, systolic blood pressure of 100 mmHg or less, and altered mental status) is a new bedside index proposed to help identify patients with suspected infection at risk of complications. We hypothesized that qSOFA scores would be associated with in-hospital mortality, ICU admission, and length of stay (LOS) in patients with burns. We performed a retrospective review of all burn patients admitted between January 2010-March 2017 at an academic, suburban, hospital with a regional burn center. qSOFA scores were calculated as 1 point each for GCS<15, RR≥22, and SBP≤100. A qSOFA value of>2 was considered high risk. Revised Baux (rBaux) scores were calculated as age +%TBSA burned +17 (if inhalation injury). A rBaux score >140 was considered high risk. Univariate, multivariate and receiver operating characteristics analyses were performed to compare qSOFA and rBaux scores. There were 1039 burn admissions during the study period. Mean age was 30 ± 24 years, 66% were male. Mean TBSA was 10 ± 12%, mean injury severity score was 5 ± 8. Mean hospital LOS was 8 ± 24 days, 22 patients (2.1%) died. qSOFA scores were associated with mortality and ICU admission. Of all patients, 80 were high risk by qSOFA and 7 by Baux scores. ROC characteristics of qSOFA and Baux scores for predicting death were sensitivity 36% vs. 32%, specificity 94% vs. 100%, PPV 13% vs. 100%, and NPV 98% vs. 99% respectively. The AUC for qSOFA (0.68 [95% CI, 0.54-0.81]) was lower than for Baux (0.99 [95%CI, 0.99-1.00]). Youden's index identified an optimal cutoff of 85 on the Baux score yielding sensitivity 100%, specificity 94%, PPV 27%, and NPV 100% for mortality. Our results indicate that while qSOFA scores were associated with outcomes, a rBaux score had greater predictive value. The optimal rBaux score for predicting all mortality and ICU admission was 85.

Keywords: Baux score; Burns; Length-of-stay; qSOFA.