Comparison of methods of predicting burn mortality.

Recent suggestions that patients "hopelessly burned" be permitted to die peacefully have refocused attention on the accuracy of different methods of predicting whether an individual burn patient will survive. The purpose of this presentation is to compare the accuracy of mortality predictions based upon four different statistical methods: (1) Baux's rule which adds the patient's age in years to the percentage of his body surface area burned--the original assertion was that values over 75 meant a very poor prognosis. (2) probit analysis, (3) discriminant analysis, and (4) logistic risk function analysis. Each of these methods was applied to data for over three thousand consecutive admissions to St. Mary's Hospital Burn Center in Milwaukee, Wisconsin. This data base and the four statistical models are described. Mortality predictions derived from the four models are compared, and some observations are made concerning the selection of an appropriate model for predicting burn mortality.