Age-dependent influence of premorbid underweight status on mortality in severe burn patients: An administrative database study.

Abstract

To examine the associations between premorbid nutritional status and in-hospital mortality in severe burn patients according to age in Japan. We retrospectively extracted the data of 14,345 patients aged 18-84 years admitted for burns from April 1, 2014, to March 31, 2018, using the Japanese Diagnosis Procedure Combination database. The exclusion criteria were out-of-hospital cardiac arrest, death in the emergency room, readmission, and planned admission. We collected data on age, sex, height, weight, comorbidities, burn index, and mechanical ventilation use and performed age-stratified multilevel logistic regression analyses to estimate associations between premorbid body mass index (BMI) and in-hospital mortality. We analyzed 2968 patients with a burn index ≥10, including 831 elderly aged 75-84 years. In patients aged 18-74 years, being underweight (BMI < 18.5) significantly decreased mortality (0.34 [0.15-0.77]; P = 0.010). In contrast, in patients aged 75-84 years, being underweight significantly increased mortality (2.11 [1.05-4.25]; P = 0.036). Being overweight (BMI >25) increased mortality in both age groups, but not significantly. The results suggest that pre-morbidly underweight elderly patients aged 75-84 years with severe burns have high mortality risks. Further research is needed to identify optimal care strategies for this population.