Incidences of underlying causes of hypothermia in older patients in the emergency department: a systematic review

Purpose: Hypothermia is a serious condition in older adults. Knowledge of a priori chances of underlying diseases may affect initial management, hence prognosis. This systematic review provided an overview of existing literature on the incidences of underlying causes of hypothermia in older patients at the emergency department. Methods: MEDLINE, The Cochrane Library, and Embase were searched up to February 1st, 2022. Inclusion criteria were age ≥ 65 years, emergency department setting, and body temperature < 36.0 degrees Celsius. Exclusion criteria were iatrogenic hypothermia, no underlying cause reported, and patient selection based on specific diseases. Title/abstract and full-text were screened and quality was assessed using the Joanna Briggs Institute Critical Appraisal Tool. Data were presented using descriptive statistics and narrative analyses. Results: Forty-one reports were included, including 6 cohort studies and 35 case reports. The 6 studies involved 2173 hypothermic patients, whose age varied from a mean of 67 to a median of 79 years and temperature from a median of 30.8 to a mean of 33.7 degrees Celsius. One study reported about primary hypothermia (incidence of 44%). Acute medical illness was often reported as underlying cause of secondary hypothermia (49–51%). Reported incidences of infection and sepsis ranged from 10 to 32%, of trauma up to 14%, and of alcohol intoxication from 5 to 26%. Conclusion: Limited studies have been published regarding this topic, and the overall quality of the evidence was graded as low. Causes that should not be missed include acute medical illness, trauma, alcohol intoxication, primary hypothermia, thyroid failure, and drug-induced hypothermia.