Asthma experts say the finding is a surprise because some previous studies have shown that statin drugs have anti-inflammatory properties beyond their cholesterol-lowering effects that may help conditions like asthma.
So, researchers are not building a case right now for you to change your medications, but to talk to your doctor if you have asthma and high cholesterol. They also say this is a call to do more research on the topic.
Asthma Patients and Statin Drugs
The new study -- being presented at the annual meeting of the American College of Allergy, Asthma, and Immunology in Boston -- followed 40 asthma patients who were treated at the same California clinic for one year.
Twenty patients had just begun statin medications to lower cholesterol at the start of the study. Twenty others who were not taking statins were followed for comparison. All were nonsmokers who had been diagnosed with asthma for at least five years.
Patients were excluded from the study if an asthma attack had landed them in the hospital or emergency room in the eight months leading up to the study. Other than asthma or high cholesterol, patients in the study were free of health problems, researchers say.
Doctors checked in with patients in the study every three months. They asked about symptoms and medication use, and they tested lung function.
After one year, patients taking statins performed 35% worse in a test of lung function than they did at the start of the study. Patients who were not taking statins also saw their lung function decline, but it was about 14% worse compared to how they performed at the start of the study.
Patients on statins also reported that they had used their rescue medications [inhalers] 72% more often than they had at the start of the study. Those who weren't taking statins used rescue medications 9% more than they had before.
Patients on statins also reported getting up more frequently at night because of their asthma and said they had worse symptoms during the day.
Those findings are associations. The study wasn't able to prove that statins caused the increase in breathing problems.
An alternative explanation could be that people who were prescribed statins simply had more health problems, overall, than those who weren't taking the drugs, although researchers say they tried to balance the groups in the study to make sure that was not the case.
The findings echo a previous study that looked at the medical records of 759 asthma patients treated at the same clinic in Rochester, N.Y. In that study, 24 patients who were starting statins saw significant drops in lung function, needed more medication, had more nighttime asthma problems, and were seen in the office more frequently compared to 26 patients who were not taking those medications.
Larger studies on the effects of statins in asthma have been contradictory, however, with some showing that statins offer modest benefits to breathing while others have found no net benefit or harm from the medications.
"There are many studies showing the opposite of what I'm saying," says researcher Safa M. Nsouli, MD, an allergist who is director of the Danville Asthma and Allergy Clinic, in Danville, Calif.
Nsouli says he became interested in the question after he noticed that many of his asthma patients who started statin therapy saw their breathing problems escalate.
He says that statins may aggravate asthma because they create an imbalance in immune system cells called helper T cells. Helper T cells fight infection by cranking out chemicals that activate and direct other immune cells to go after invaders.
Statins work, in part, by lowering levels of one kind of helper T cell. To compensate, Nsouli says, the body makes more of a second kind of helper T cell. Those cells are particularly bad for people with asthma triggered by allergy (allergic asthma) because they increase inflammation in the airways.
Advice to People With Asthma
Nsouli acknowledges that his study is small and says it's not a reason for anyone to stop taking a prescribed statin.
"The goal of my study is to make aware the patients who have allergies and asthma to know that being on statins, this might imbalance their immune system and might ... adversely affect their asthma," he tells WebMD. "Therefore they have to be medicated more carefully and more aggressively by their allergy and asthma specialist, rather than forgoing statins."
Other experts agree that the findings are interesting and could be important if they are confirmed in larger studies.
Statins are among the most widely prescribed medications in the U.S. -- taken by an estimated one in four Americans over age 45. Government reports show that about one in 12 adults has asthma.
"The size of the study is quite small," says David Beuther, MD, a pulmonologist and assistant professor of medicine at National Jewish Health in Denver.
"I think it's a signal we need pay attention to make sure that we look into this in more detail and confirm it in other studies before we get too excited about it," Beuther tells WebMD. "But it's probably worth pursuing."
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.