Researchers supported by the National Institutes of Health have found that dual bronchodilators (long-acting inhalers that relax the airways and make breathing easier) do little to help people who do not have chronic obstructive pulmonary disease (COPD), but do. respiratory symptoms and smoking history.
COPD, a lung disease that obstructs the airways and causes coughing, wheezing and shortness of breath, affects about 15 million Americans. However, millions of other people who smoke or used to smoke and have some symptoms of COPD are also prescribed bronchodilators.
“We assumed that these drugs worked in patients who did not meet the lung function criteria for COPD, but we never tested it,” said MeiLan K. Han, MD, principal investigator and first author of the study. “Now we know that these existing drugs don’t work for these patients.”
The findings of the study, which was funded by the National Heart, Lung, and Blood Institute (NHLBI), were published in the New England Journal of Medicine and presented simultaneously at the International Congress of the European Respiratory Society.
According to the scientists, the implications are significant. First, they show the importance of diagnosing lung conditions using spirometry, a lung function test that Han noted is underutilized in clinical practice. Second, they show the need for new effective therapies for patients without COPD.
Inhalers have long been the main treatment for these patients, he explained, because doctors assume that a patient has COPD or, if not, that their smoking-related symptoms could be helped by inhalers. But while tobacco causes a wide spectrum of lung damage, the study showed that bronchodilator therapy only helps patients with enough lung damage that would result in abnormal spirometry readings.
In the 12-week, randomized, double-blind study, which was part of the Redefine Therapy in Early COPD for the Lung Trials Cooperative (RETHINC), researchers enrolled 535 adults with COPD symptoms, from between 40 and 80 years, in one of the 20 medical centers in the USA. Twice a day, study participants used an inhaler containing medication or a placebo.
At the end of the trial, some adults in the medication (intervention) and placebo (control) groups saw slight respiratory improvements, which could mean they coughed less, produced less phlegm, or felt less discouraged, as assessed by of St. George’s. Respiratory Questionnaire. However, the researchers found no significant differences between those receiving medication or placebo. They reported that 56% (128 of 227) of participants who received the drug saw improvements in respiratory symptoms, compared with 59% (144 of 244) of those who took the placebo.
According to Han, these data underscore why we can’t continue to do what we’ve been doing, which is not doing spirometry and just treating patients with the same COPD medications and hoping we’ll see improvements.
Antonello Punturieri, MD, Ph.D., program director of NHLBI’s Chronic Obstructive Pulmonary Disease/Environment Program, said spirometry testing should be used for any patient showing signs of COPD, airflow obstruction or who has a history of smoking. Although spirometry readings are used for approximately one-third of COPD-related medical visits, approximately half of patients who meet COPD criteria are undiagnosed.
Helping patients quit smoking is a primary way to prevent COPD or COPD-like symptoms, the study noted. More than 30 million adults smoke, according to the Centers for Disease Control and Prevention, and many who are undiagnosed with COPD share symptoms. About one in four current or former smokers without COPD have reported having difficulty breathing. In addition to encouraging smoking cessation, doctors can help patients who do not meet lung function criteria for COPD by working with them to address other underlying problems, such as overweight and obesity, heart failure, or other problems pulmonary
“In the meantime, research should focus on finding new treatments for them,” Han explained. “The next question is, can we develop more targeted therapies for these patients who are on the milder end of the spectrum?”
“Because cough and mucus production feature prominently among these patients, we believe that therapies targeting airway mucus production may be effective,” said Prescott G. Woodruff, MD, principal investigator and author principal of the study.
Some of these therapies are already in development, and data from other studies may offer insight into the biological causes of excess airway mucus. These clues could help researchers identify additional therapies.
For more information on lung health, visit https://www.nhlbi.nih.gov/BreatheBetter.
For information about RETHINC and the Pulmonary Trials Cooperative, visit https://www.pulmonarytrials.org/ptc-studies/rethinc/.
To study:
Han MK, Ye W, Wang D, et al. Bronchodilators in symptomatic tobacco-exposed individuals with preserved spirometry for the RETHINC study group. N Engl J Med. 2022; doi: 10.1056/NEJMoa2204752.
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