Sick of the Heat

Respiratory hospitalizations can increase with outdoor heat among elderly

/ Author:  / Reviewed by: Chris Galloway, M.D.

(RxWiki News) Everybody wants to keep cool during the heat of the summer. New research shows that beating the heat may be especially important for the elderly with breathing problems.

A recent study found that hospitalization rates among patients aged 65 years or older with respiratory problems were linked to outdoor temperatures.

Researchers looked at Medicare records for 12.5 million patients to see if there was a relationship between the weather outside and hospitalizations for chronic obstructive pulmonary disease (COPD) and respiratory infections among the elderly.

The results showed that the hotter it got, the more hospitalizations there were.

"Stay cool when it’s hot outside!"

Researchers led by G. Brooke Anderson, PhD, of the Johns Hopkins Bloomberg School of Public Health, wanted to find out if the elderly population’s risk of hospitalization for respiratory diseases was linked to outdoor heat.

To carry out the study, the researchers looked at Medicare records between the years 1999 and 2008 to determine the rates of emergency hospitalization among the elderly for respiratory sickness during that period.

Over 12.5 million Medicare beneficiaries from 213 urban counties across the United States were studied. Over 30 percent of the patients were 65 years old or older.

Participants had been admitted to the hospital for COPD or respiratory infections.

The researchers recorded the regional air pollution rates and weather conditions for the time of the hospitalizations.

Their analysis showed that on average, emergency respiratory hospitalizations for patients aged 65 and above increased 4.3 percent for each 10 degree Fahrenheit increase in average daily summer temperatures.

They found that the link between elderly respiratory hospitalization rates and temperature was strongest on the days with the highest heat. The increased hospitalization rates remained high for a day after the peak temperature.

When the researchers distinguished between hospitalizations caused by COPD symptoms and those caused by respiratory tract infections, they only found a small difference.

On average, emergency COPD hospital admission rates increased 4.7 percent for each average temperature increase of 10 degrees Fahrenheit while there was a 4.1 percent increase for respiratory tract infections.

The researchers estimated that for each 10 degree increase in daily temperature, there were approximately 30 extra respiratory hospitalizations per day among the elderly in the 213 counties studied.

"Our study provides clear and consistent evidence of a link between outdoor heat and hospitalization for respiratory disease in the elderly," said co-author Roger D. Peng, PhD, of the Department of Biostatistics at the Johns Hopkins Bloomberg School of Public Health.

"As the prevalence of respiratory conditions and the age of the population continue to increase and global temperatures continue to rise as a result of climate change, the risk of heat-related respiratory disease is also likely to increase," he said.

The study was published online on March 14 in the American Journal of Respiratory and Critical Care Medicine.

The research was funded by the National Institute for Environmental Health Sciences and the US Environmental Protection Agency. The study authors reported no conflicts of interest.

Reviewed by: 
Review Date: 
March 14, 2013
Last Updated:
August 16, 2013