In a debate-like session, Donald P. Tashkin, MD, of the University of California Los Angeles Medicine, and Ray Stokes Peebles, Jr., MD, FAAAAI, of Vanderbilt University Medical Center in Nashville, Tennessee, discussed whether asthma and chronic obstructive pulmonary disease (COPD) overlap (ACO) is a distinct syndrome that impacts treatment and outcomes during a session at the 2018 AAAAI Annual Meeting.
The overlap of asthma and COPD stems from the “Dutch hypothesis,” which was originally proposed by Professor N.G.M. “Dick” Orie and his team at the University of Groningen in the Netherlands in 1961. Although Dr. Tashkin was to argue that ACO is a distinct syndrome that changes treatment patient outcomes, he conceded that he does not believe ACO is a distinct syndrome, but he also does not consider asthma or COPD distinct either. “All of these are heterogeneous, with different phenotypes and paths of physiology,” he said.
The difficulty in discussing ACO is that there is no consensus on diagnostic criteria; therefore, clinical studies on the topic have had varying outcomes. Many groups have tried to define and propose criteria for ACO, with some overlap. Consensus remains to be seen on whether it should be defined clinically (age, physiology, symptom variability, personal or family history of asthma), with biomarkers (eosinophil, immunoglobulin E, fractional exhaled nitric oxide), or a combination of both. However, research has shown that ACO is associated with worse outcomes than COPD or asthma alone. There is also consensus around the thought that an inhaled corticosteroid should be part of the treatment regimen for ACO. “It is not yet clear how ACO is best defined, unfortunately,” he said. “But clearly, there are patients who have features of both COPD and asthma.”
Dr. Peebles then argued that while ACO exists—“We’ve known about ACO for a long time,” he said—he does not believe it is a distinct syndrome that should impact treatment choice. Since the 1970s, the number of articles published on this topic has grown. In 2017 and the first two months of 2018, 159 studies were published about ACO, with an uptake in this research observed beginning in 2013. However, Dr. Peebles noted, there are more review articles than original research articles, which is “a real problem.” There are also more retrospective than prospective trials. “That tells you we don’t know what we’re doing, but know it exists,” he noted. Because there is no consensus on definition, trial populations of those in asthma and COPD studies are different and conflicting, making this even more difficult to study.
“What if you were to call it COPD overlaps asthma syndrome? You get CAOS,” he said, pronouncing it as chaos, “and I think that’s where we are right now,” he concluded, eliciting a bout of laughter from the audience.
For more information, read our exclusive interview with Dr. Tashkin on this topic.
Presentation 2553: The Overlap of Asthma and COPD (ACOS) is a Distinct Syndrome that Changes Treatment and Patient Outcomes