title: Validation of the prognostic burn index: a nationwide retrospective study.
abstract: BACKGROUND
  The burn index (BI=full thickness total burn surface area [TBSA]+1/2 partial thickness TBSA) and prognostic burn index (PBI=BI+age) are clinically used particularly in Japan. However, few studies evaluated the validation of PBI with large sample size. We retrospectively investigated the relationships between PBI and mortality among burn patients using data from a nationwide database.
  
  
  METHODS
  Data of all burn patients with burn index ≥1 were extracted from the Japanese Diagnosis Procedure Combination (DPC) inpatient database from 1 July 2010 to 31 March 2013 (17,185 patients in 1044 hospitals). The primary endpoint was all-cause in-hospital mortality.
  
  
  RESULTS
  Overall in-hospital mortality was 5.9% (1011/17,185). Mortality increased significantly as the PBI increased (Mantel-Haenszel trend test, P<0.001). The area under the receiver operating characteristic curve for PBI was 0.90 (95%CI, 0.90-0.91), and a PBI above a threshold of 85 showed the highest association with in-hospital mortality. Logistic regression analysis showed that PBI≥85 (odds ratio (OR), 14.6; 95%CI, 12.1-17.6), inhalation injury with mechanical ventilation (OR, 13.0; 95%CI, 10.8-15.7), Charlson Comorbidity Index≥2 (OR, 1.8; 95%CI, 1.5-2.3), and male gender (OR, 1.5; 95%CI, 1.3-1.8) were significant independent risk factors for death.
  
  
  CONCLUSIONS
  Our study suggested that a PBI above a threshold of 85 was significantly associated with mortality. The PBI and mechanical ventilation were the most significant factors predicting in-hospital mortality, after adjustment for inhalation injury, comorbidity, and gender.
authors.affiliation: Department of Clinical Epidemiology and Health Economics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo 1130033, Japan; Department of Emergency and Critical Care Medicine, Nippon Medical School, Tokyo 1138603, Japan. Electronic address: t-tagami@nms.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tagami
authors.affiliation: Department of Clinical Epidemiology and Health Economics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo 1130033, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Matsui
authors.affiliation: Department of Health Informatics and Policy, Tokyo Medical and Dental University, Graduate School of Medicine, Tokyo 1138519, Japan.
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Fushimi
authors.affiliation: Department of Clinical Epidemiology and Health Economics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo 1130033, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasunaga
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001830:Body Surface Area; D002056:Burns / Q000453:epidemiology / Q000401:mortality*; D015331:Cohort Studies; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D012372:ROC Curve; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D015208:Smoke Inhalation Injury / Q000453:epidemiology; D015599:Trauma Severity Indices
keywords: Burns; Database; Inhalation injury; Mortality; Prognosis