Researchers found that in about a third of cases, poor compliance with treatment was a major factor in difficult-to-treat asthma.
"There are a lot of reasons patients don't take their medications as they should," researcher Jacqueline Gamble of Queen's University of Belfast tells WebMD. "Some of these treatments have side effects that are not pleasant, especially oral corticosteroids. If patients aren't honest, or feel they can't be honest with their doctors about this, there is very little way to know."
Worldwide, about 300 million people have asthma, including 23 million in the U.S.
Every day in the U.S., 30,000 people have asthma attacks, 1,000 asthma patients are admitted to hospitals, and 11 people die of the respiratory disease, according to the Asthma and Allergy Foundation of America.
Poor treatment compliance has long been recognized as a significant issue in the management of asthma, but the scope of the problem is not well understood because objective measurement is difficult.
In the new study, Gamble and colleagues from Belfast City Hospital assessed compliance with treatment in 182 consecutive patients attending a clinic specializing in difficult-to-treat asthma.
Among patients prescribed a maintenance course of oral steroid, the blood analysis showed that nearly half (45%) were not taking their medication as prescribed. And more than half of these patients (65%) were also noncompliant with their inhaled treatment.
All of the poorly compliant patients had initially denied taking less of their medications than they were prescribed.
Women were more likely than men to be poorly compliant, and patients who scored lower on quality-of-life assessments were also less likely to take their medications as directed.
Many Reasons for Poor Compliance
"Our experience suggests that not all patients have the same reasons for poor adherence, and therefore a one-size-fits-all intervention is unlikely to be appropriate," the researchers write in the November issue of the American Journal of Respiratory and Critical Care Medicine.
American Thoracic Society past president John E. Heffner, MD, agrees there are many reasons why people with asthma fail to take their medications as prescribed.
"In cases where noncompliance is unintentional, poor communication is often a big part of the problem," he tells WebMD. "Physicians may not communicate instructions appropriately or give written instructions that can be easily followed."
Patients may also intentionally fail to take their medications because they are bothered by side effects or underestimate the seriousness of their disease.
He says patients need to educate themselves about their asthma and doctors need to understand that different patients may benefit from different approaches to treatment.
Heffner, a professor of medicine at Providence Portland Medical Center, says, "Physicians need to tailor therapy in a manner that meets the individual medical, psychological, and social needs of the patient so that the patient has the greatest opportunity to be compliant."