BACKGROUND: Heat-related health outcomes (HRO) are highly preventable through behavioral modifications, early symptoms identification, and rapid intervention. HRO surveillance systems, including the use of syndromic surveillance, track the burden of disease and inform targeting of high-risk groups for prevention activities. The current North Carolina (NC) HRO surveillance system is limited as it does not capture cases treated outside the ED/hospital or provide information on the incident location. This analysis was conducted to determine if Emergency Medical Services (EMS) data could contribute to the surveillance system.
METHODS: In NC, EMS data are collected through the Pre-hospital medical information system (PreMis) and a subset is provided to the NC syndromic surveillance system (NC DETECT). EMS data from May-September, 2015 were obtained via NC DETECT. HRO call-outs were identified by a dispatch complaint of heat/cold exposure or a heat-related key-word in the patient complaint fields. Manual review was also conducted to identify additional HRO call-outs. EMS and ED date were linked to determine case concordance. Descriptive statistics were completed.
RESULTS: For this analysis, 1,968 HRO EMS call-outs were identified; 41.8% fewer cases than identified by the ED-based syndromic surveillance system. Fifty-one percent (n=1,002) were identified by patient complaint key-word, 47.6% (n=936) by dispatch complaint, and 1.5% (n=30) by manual review. Sixty-eight percent of patients were male (n=1336) with a mean patient age of 46 years. Only 2.2% (n=44) of HRO call-outs were marked as work-related; however, 40.4% (n=796) of HRO call-outs had a missing value for work-related status. Among NC residents, the majority of HRO call-outs occurred in the patient’s city (60.2%, n=1,079) or county of residence (70.5% n=1,263). Seventy-three percent (n=1,429) of patients were transported to the ED while 14.0% (n=276) refused treatment and 13.0% (n=255) were treated and released. Males were more likely than females to be transported to the ED versus refusing treatment or being treated and released (chi-square=32.8, p<0.0001). Patients whose incident occurred in their city of residence were also more likely than those who were not residents to be transported to the ED (chi-square=4.7, p=0.03).
CONCLUSIONS: Most HRO EMS call-outs occurred to individuals within their own community, suggesting prevention messages target residential and community-specific activities. Review of the EMS data indicated a difference between ED transported cases and those not seen in the ED. As such, the EMS data housed in NC DETECT could be a beneficial addition to the current HRO syndromic surveillance conducted at the state and local levels.