ED Visits for Asthma, COPD Spike Before Thunderstorms Among Medicare Beneficiaries

August 16, 2020

A long-term study of over 46 million Medicare beneficiaries found that emergency department (ED) visits for acute respiratory illnesses such as asthma or COPD sharply increased in the days before a major thunderstorm.

A new research letter appearing in JAMA Internal Medicine has revealed that thunderstorms don’t bode well for the respiratory health of older Americans, particularly those with respiratory disease. According to the researchers’ findings, emergency department (ED) visits for acute respiratory illness sharply increased in the days before a major thunderstorm, particularly among those with asthma or chronic obstructive pulmonary disease (COPD).

The large-scale study findings come from over 46 million Medicare beneficiaries, 10.5% of whom had asthma, 26.5% had COPD, and 6.6% had both. Among all beneficiaries, there was a mean 1.8 additional visits the day before a major storm, corresponding to a 1.2% increase.

These thunderstorms, characterized by lightning, precipitation, and above-median wind speed, were associated with temperature increases and particulate matter prior to the storm and associated with declining levels on the day of and the days following the storm. The days following the storm were also associated with declining pollen counts, nitrogen dioxide levels, ozone, sulfur dioxide, and carbon monoxide.

“Visits were temporally associated with rises in temperature and particulate matter concentrations, atmospheric changes that have previously been associated with acute respiratory illness in the Medicare population,” explained the researchers.

Individuals with asthma or COPD, or both, fared worse. These patients accounted for the highest mean increase in ED visits, which peaked the day before a major storm. There were:

  • 6.3 additional ED visits per million beneficiaries for patients with asthma, corresponding to an increase of 1.1%
  • 6.4 additional ED visits per million beneficiaries for patients with COPD, corresponding to a 1.2% increase
  • 9.4 additional ED visits per million beneficiaries for patients with asthma and COPD, corresponding to a 1.2% increase

According to the researchers, it’s been hypothesized that rare epidemics of asthma following thunderstorms are a result of pollen grains rupturing when wet, which then allows winds to carry small pollen particles and thus triggers asthma in susceptible patients. However, since the ED visits peaked before the thunderstorms, it was likely not pollen particle release primarily responsible.

“Assuming an average 65 years or older population of 37.7 million Americans (based on census data), approximately 52,000 additional respiratory ED visits were estimated to occur in the 3 or more days surrounding major storms during the 14-year study period,” noted the researchers, who used publicly available data from 1999 through 2012.

In the 3 or more days surrounding the storms, there were 22.6 additional visits per million beneficiaries among patients with asthma, 22.4 additional visits among patients with COPD, and 33.8 additional visits among patients with both conditions. Across all beneficiaries, there were 5.3 additional visits.

The researchers also performed a falsification analysis for certain unmeasured variables that might also increase the risk of ED visits before a major thunderstorm, such as sepsis and pulmonary embolism, and found no association between these confounders and thunderstorms.

Reference

Zhou E, Worsham C, Miller N, Molitor D, Reif J, Jena A. Emergency visits for thunderstorm-related respiratory illnesses among older adults. JAMA Intern Med. Published online August 10, 2020. doi: 10.1001/jamainternmed.2020.1672.