While advanced therapies approved for either should be considered for ACO patients, there hasn't be sole investigations.
Overlap between asthma and chronic obstructive pulmonary disease (COPD) is large, loosely defined, and vastly varying.
In a therapy-focused lecture on Asthma/COPD Overlap (ACO), Diego Maselli Caceres, MD, FCCP, assitant professor at the University of Texas Health Science Center at San Antonio, explained to an audience at the 2017 Annual CHEST Meeting in Toronto, ON, CA, that it’s not enough to configure a treatment for the comprehensive disease.
Rather, the big question lies in which disease subset has more weight in a patient. Caceres is not yet sure how that can be done.
The major criteria to diagnose an ACO patient features 3 symptoms, Caceres said. Patients 40 years or older would have persistent airflow limitation despite bronchidilators; they would have a 10 pack-year or equivalent exposure to smoking; and they would either be diagnosed for asthma before age 40, or have a bronchodilator response of more than 400 ml in their first forced expiratory volume (FEV1).
Minor criteria includes atopy, bronchodilator response of more than 200 ml in FEV1, and a peripheral eosinophilis of more than 300 cells/microliters, Caceres said.
The overlap of the 2 pulmonologic diseases can be found in varying elements, though: smokers with eosinophilic inflammation, asthma with steroid resistance, smokers with asthma, or asthma with airway remodeling.
The outright definition of ACO continues to be an “area of controversy,” Caceres told MD Magazine. Clinicians have to keep their eyes open for the disease combination.
“On a day-to-day basis, we see these patients that have both diseases, and we need to be using as much information as we can, starting from the clinical history regarding exposures like smoking or biomass,” Caceres said. “There’s a very strong emphasis on the history of allergic diseases as a child or a young person. These are things that factor into the equation.”
Unfortunately, therapeutic investigation is still behind. Severe asthma studies have excluded COPD cases, and vice versa, Caceres said. Though a combination treatment of long-acting beta antagonists (LABA) and long-acting muscarinic antagonists (LAMA) is advised for chronic airway diseases, there is no bridging therapy.
Caceres made note of therapies that have shown a reduced rate of exacerbations for either conditions in respective trials — azithromycin for asthma, anti Immunogoblin E (anti-IgE) therapy for COPD, and mepolizumab (anti-IL5) in eosinophilic COPD. Advanced therapies approved for either condition shouldn’t be withheld for patients with overlapping conditions similar to ACO, Caceres said.
While future clinical trials should hone in on the particularities of ACO pathology, symptoms and pharmacology, Caceres told MD Magazine that physicians could aid from focusing on patients’ past.
“In the end, it’s always difficult to know how much each weight of disease is causing the condition,” Cacares said. “Is it just asthma that has been activated or is it emphysema that has progressed? I think that’s very difficult to phase out, but I think that the more information we have from patient history helps us understand.”