Predictors of hospitalization in male Marine Corps recruits with exertional heat illness.

Exertional heat illness can have serious consequences and is a common cause of hospitalization during basic military training. The objective of this case-control study was to determine risk factors for hospitalization in male Marine Corps recruits who received medical care for heat illness during their basic military training course at Parris Island, South Carolina. Of 565 heat casualties, 61 (11%) were hospitalized (case subjects) and 504 were treated as outpatients (control subjects). Using univariate and multivariate analyses, demographic, clinical, and laboratory factors were assessed to determine predictors of hospitalization. Nineteen of the 24 analyzed variables were significantly associated with hospitalization. Three clinical variables (disorientation, rectal temperature, systolic blood pressure) and three laboratory variables (serum lactate dehydrogenase, potassium, and creatinine values) were highly predictive for hospitalization in recruits with exertional heat illness. A simple scoring system using these six variables predicted hospitalization with 87% sensitivity, 91% specificity, and a likelihood ratio of 9.7.