Definition

Count 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).

Numerator

Count of inpatient hospitalizations or emergency department visits for heat related illnesses among a defined population during the months of May through September.

Denominator

Defined population in a specified time interval.

How Are We Doing?

In New Jersey, the total number of days over 90 degrees F has increased by roughly 40 percent since 1949. On average throughout the state, the number of days over 90 degrees F have increased from about 17 to 23 per year. Extreme heat events are predicted to increase in both intensity and duration in future years. New Jersey generally experiences two heat waves per year with temperatures exceeding 90 F, and the heat waves last about four days. By the mid-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 mid-2020s.

What Is Being Done?

The NJDOH is using data collected from emergency departments and hospitals to identify and track excessive heat related illnesses among New Jersey's residents. NJDOH will use the information to implement targeted extreme heat event notification and actions that focus surveillance and relief efforts on high risk populations or communities.