A novel early risk assessment tool for detecting clinical outcomes in patients with heat-related illness (J-ERATO score): Development and validation in independent cohorts in Japan.

Kei Hayashida,Toru Hifumi,Shinichiro Shiraishi,Tatsuma Fukuda,Junichi Sasaki,Junya Shimazaki,Yasutaka Oda,Yutaka Kondo,Keiki Shimizu

doi:10.1371/journal.pone.0197032

Abstract

BackgroundWe sought to develop a novel risk assessment tool to predict the clinical outcomes after heat-related illness.MethodsProspective, multicenter observational study. Patients who transferred to emergency hospitals in Japan with heat-related illness were registered. The sample was divided into two parts: 60% to construct the score and 40% to validate it. A binary logistic regression model was used to predict hospital admission as a primary outcome. The resulting model was transformed into a scoring system.ResultsA total of 3,001 eligible patients were analyzed. There was no difference in variables between development and validation cohorts. Based on the result of a logistic regression model in the development phase (n = 1,805), the J-ERATO score was defined as the sum of the six binary components in the prehospital setting (respiratory rate≥22 /min, Glasgow coma scale<15, systolic blood pressure≤100 mmHg, heart rate≥100 bpm, body temperature≥38°C, and age≥65 y), for a total score ranging from 0 to 6. In the validation phase (n = 1,196), the score had excellent discrimination (C-statistic 0.84; 95% CI 0.79–0.89, p<0.0001) and calibration (P>0.2 by Hosmer-Lemeshow test). The observed proportion of hospital admission increased with increasing J-ERATO score (score = 0, 5.0%; score = 1, 15.0%; score = 2, 24.6%; score = 3, 38.6%; score = 4, 68.0%; score = 5, 85.2%; score = 6, 96.4%). Multivariate analyses showed that the J-ERATO score was an independent positive predictor of hospital admission (adjusted OR, 2.43; 95% CI, 2.06–2.87; P<0.001), intensive care unit (ICU) admission (3.73; 2.95–4.72; P<0.001) and in-hospital mortality (1.65; 1.18–2.32; P = 0.004).ConclusionsThe J-ERATO score is simply assessed and can facilitate the identification of patients with higher risk of heat-related hospitalization. This scoring system is also significantly associated with the higher likelihood of ICU admission and in-hospital mortality after heat-related hospitalization.

Highlights

Exposure to high ambient temperatures can be deadly, making extreme summer heat a serious global public health threat [1,2,3]
The observed proportion of hospital admission increased with increasing J-ERATO score
Multivariate analyses showed that the J-ERATO score was an independent positive predictor of hospital admission, intensive care unit (ICU) admission (3.73; 2.95–4.72; P

Summary

Introduction

Exposure to high ambient temperatures can be deadly, making extreme summer heat a serious global public health threat [1,2,3]. The association of extreme summer heat with excess mortality and morbidity has been well documented in the last decades. While evidence suggests the adverse impacts of heat waves on human health in many regions [7], the morbidity and mortality related to heat condition are reduced by appropriate preventions and treatments [8]. Clinical studies with a large cohort, which investigated an early warning system to assess the outcomes of heat illness, are extremely limited. We sought to develop a novel risk assessment tool to predict the clinical outcomes after heat-related illness

Methods

Results

Conclusion