Relationship Between Environmental Heat Morbidity and Mortality Cases During Years 2008-2013, Maricopa County

Background: Between January 2008 and December 2013 there were 9,414 hospital encounters and 496 deaths attributed to environmental heat in Maricopa County. Although, Maricopa County Department of Public Health (MCDPH) captures heat related deaths (HRD) that occur in the hospital it was unknown if any HRD had previous hospital encounters related to environmental heat which might indicate repeated exposures and increased risk for adverse health outcomes. Therefore, this study sought to determine the number of HRD that had a previous environmental heat related hospital encounter both immediately prior to death and at any time in the past.

Method: To determine the proportion of HRD with prior environmental heat related hospital encounters, a data match was performed between known HRD, occurring between 2008-2013, and hospital discharges with environmental heat diagnosis occurring during the same time period.

Results: Of the 496 known HRD, MCDPH identified 82 matching hospital encounters, representing 76 (15%) individuals.  A small percentage of individuals (1.3%) had multiple encounters during the study period and are not included in the following analysis.

Of the 71 remaining hospital encounters, 57 (80%) resulted in admission with a median length of stay (LOS) of 3 days (range 1-47 days).  Seventy percent (N=50) of individuals that had a hospital encounter died during that hospital encounter.  For those that were discharged, (N=16), from the facility and died within the same year the mean number of days between discharge and death was 6 (range 1-45 days). 

Discussion: Although many are acutely affected by environmental heat, for some, environmental heat can be a chronic issue eventually contributing to their death.  This study suggests that some individuals had multiple events of heat-stress prior to their death which indicates an opportunity for intervention.