Smoking History May Help Classify Asthma-COPD Overlap

Information regarding patients’ smoking history can help practitioners differentiate between asthma-COPD (chronic obstructive pulmonary disease) overlap (ACO) vs asthma with chronic airflow obstruction, according to a recent study. Furthermore, patients’ emphysema status was useful in classifying ACO.

From 2000 to 2016, the researchers assessed the deaths and exacerbation frequencies of 256 patients with ACO (161 with emphysema and 95 without emphysema) with at least 10 pack-years of smoking history, as well as 64 asthma patients with chronic obstructive airflow and less than 10 years of smoking history, and 537 patients with COPD (452 with emphysema and 85 without emphysema).
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Causes for emergent admission were classified as either COPD exacerbation, asthma attack, or other causes.

Computed tomography scan findings indicated that no patients with asthma with chronic obstructive airflow had emphysema. Ultimately, the researchers found that patients with asthma with chronic obstructive airflow had much better prognoses vs those with ACO and COPD, and patients with ACO had better prognoses than those with COPD. They also noted that patients with both ACO and COPD without emphysema had better prognoses vs those with emphysema.

Emergent admissions were more frequent among patients with COPD vs those with ACO, and in those with emphysema vs those without emphysema. Patients with ACO and emphysema were more frequently admitted due to COPD exacerbations, whereas those with ACO without emphysema were more frequently admitted due to an asthma attack.

“A smoking history (≥10 pack-years) was found to be a useful marker for differentiating ACO and asthma with [chronic airflow obstruction], and emphysema was a useful marker for classifying ACO,” the researchers concluded. “These markers are useful for predicting the overall survival and frequency of exacerbation.”

—Christina Vogt

Reference:

Kurashima K, Takaku Y, Ohta C, et al. Smoking history and emphysema in asthma–COPD overlap. Int J Chronic Obstruct Pulmon Dis. 2017;2017(12):3523-3532. https://doi.org/10.2147/COPD.S149382.