Uncontrolled asthma increases the risk of severe COVID-19, researchers warn.

"This study … focused on how COVID-19 outcomes might change for asthma patients depending on their level of asthma control," said study author Anny Xiang, a senior research scientist at Kaiser Permanente Southern California.

"We also saw that even in patients with active asthma, if they were using asthma medications their odds of worsened COVID-19 outcomes decreased, which demonstrates just how important these medications are," she added.

For the study, researchers from Kaiser Permanente and the University of Southern California (USC) analyzed medical records of more than 61,000 COVID-19 patients treated at Kaiser Permanente Southern California between March 1 and Aug. 31, 2020.

The investigators identified 2,751 patients with uncontrolled asthma and 2,775 whose asthma was controlled before their COVID-19 diagnosis. The study also included 820 patients with a history of chronic obstructive pulmonary disease (COPD).

The researchers found that patients with uncontrolled asthma had much higher rates of hospitalization, intensive breathing support and intensive care admission within 30 days of COVID diagnosis than those with no history of asthma or COPD.

A history of COPD was associated with a higher risk of hospitalization, intensive breathing support and death within 60 days from COVID-19, the findings showed.

Meanwhile, no increased risk of death within 60 days was found among patients with uncontrolled asthma, according to the report published Aug. 10 in The Journal of Allergy and Clinical Immunology: In Practice.

The findings suggest that asthma patients, especially those who require clinical care, should continue taking their asthma medications during the COVID-19 pandemic, the study authors concluded.

"Anyone with asthma should continue to work with their health care provider to ensure they are getting the best treatment for their asthma, which leads to better asthma control and decreases the likelihood of severe COVID-19 outcomes," co-lead author Zhanghua Chen, assistant professor of population and public health sciences at USC, said in a university news release.

About 25 million Americans have asthma. That's roughly one in 13 Americans, including 8% of adults and 7% of kids.