Hypothermia in a desert climate: severity score and mortality prediction

Introduction: The goal of our study was to characterize patients admitted to the hospital with hypothermia in a desert climate. Methods: This was a retrospective study (1999-2005) in a 1200-bed tertiary care hospital in southern Israel. Patients' data and weather condition (including mean day high and low temperatures, humidity, wind velocity and precipitation) within 48 hours before admission were assessed. Results: One hundred sixty-nine patients with hypothermia were admitted. The mean highest environmental temperature over 48 hours before admission was 15.3°C in the severe hypothermia (9 cases, 5.3%), 21.4°C in the moderate (40 cases, 23.7%), and 29.3°C in the mild group (120 cases, 71.0%). Major medical conditions associated with decreased body temperature were sepsis (65, 38.5%), trauma (34, 20.1%), endocrine disorders (19, 11.2%), and substance abuse (15, 8.9%). The inhospital mortality rate was 47.3%. A risk score based on 5 admission variables (age ≥70 years, mean arterial pressure <90 mm Hg, pH <7.35, creatinine >1.5 mg/dL, and confusion) was generated, predicting inhospital mortality with area under the receiver operating characteristic (ROC) curve of 0.81 (95% confidence interval, 0.75-0.87). Conclusions: Hypothermia should not be overlooked in geographical areas with temperate climates. Using a prognostication system based upon clinical and laboratory variables may identify hypothermia patients with increased risk of death.