Periods of extreme heat in the U.S. i.e. between 1999 and 2000 have been associated with an increased risk of hospitalization for older adults for fluid and electrolyte disorders, kidney failure, urinary tract infections, septicemia and heat stroke, according to scientists at Harvard School of Public Health, Boston. These weather-related outcomes are expected to escalate as heat waves become more frequent, more intense, and longer lasting with climate change.
Researchers analyzed the Medicare inpatient claims data to systematically examine possible ways in which exposure to heat waves might be associated with serious illness requiring hospitalization in older adults. Of 214 disease groups that accounted for 99.9% of hospitalizations, the five diseases- fluid and electrolyte disorders, kidney failure, urinary tract infections, septicemia and heat stroke, had statistically significantly elevated risk of hospitalization during heat wave days. This risk was larger when the heat wave periods were longer and more extreme and were largest on the heat wave day but remained elevated and statistically significant for 1 to 5 subsequent days.
Researchers said, "For some diseases, risk of hospitalization remained elevated for up to 5 days following a heat wave day. This suggests that prevention and treatment of heat-related illnesses is critical not only during the heat wave itself but also on subsequent days. Additionally, quantifying the extra number of hospital admissions attributable to heat waves without consideration of a delayed effect may underestimate the health care burden of heat."
The study is published in JAMA.