DefinitionCount or rate of hospitalization and emergency department visits for heat-related illnesses for a defined population in a specified time interval. Cases were selected using the following ICD-9 codes through September 2015: 992.0 - 992.9, E900.0, or E900.9 as a primary diagnosis, injury cause, or other diagnosis for occurrences during the months of May through September. Cases were excluded if a man-made source of heat (ICD-9 E900.1) was listed. Beginning October 2015, heat-related illness was defined by ICD-10 codes T67, X30, and X32 (exclusion W92).
NumeratorCount of inpatient hospitalizations or emergency department visits for heat related illnesses among a defined population during the months of May through September.
DenominatorDefined population in a specified time interval.
Why Is This Important?The relationship between extreme heat and increased daily morbidity is well established. This indicator captures inpatient hospital admissions or emergency department visits for heat-related illness or hyperthermia.
How Are We Doing?Average annual temperatures in New Jersey have increased about 1.2 degrees Fahrenheit (F) between the period of 1971-2000 and the period of 2001-2010.
In New Jersey, the total number of days over 90 degrees F has increased by roughly 36 percent since 1949. On average, based on data from 16 weather station locations spread across New Jersey, the number of days over 90 degrees F have increased from about 17 to 23 per year. There are however considerable temperature differences between north and south, coastal and inland, and urban and rural sections of New Jersey.
Extreme heat events are predicted to increase in both intensity and duration in future years. Currently, New Jersey generally experiences two heat waves per year with temperatures exceeding 90 F, and the heat waves last about four days. By the 2020s, it is projected that New Jersey will annually experience three to four heat waves lasting four to five days each. Annual number of days over 90 degrees F are projected to rise from an average of 14 days in 2000 to 23-29 days by the 2020s.
What Is Being Done?The NJ DOH is using data collected from emergency departments and hospitals to identify and track excessive heat related illnesses among New Jersey's residents. NJ DOH will use the information to implement targeted excessive heat event notification and actions that focus surveillance and relief efforts on high risk populations or communities. Appropriate actions include: establishing enhanced real-time syndromic surveillance systems to alert public health officials about increases in heat-related illnesses; enhancing real-time public notification regarding extreme heat events through the web, broadcast media, and social media; and enhancing access to cooling centers.