Asthma-COPD overlap syndrome is a critical, yet understudied disease, pulmonologist Dr. Navitha Ramesh tells Medscape.

Worldwide, asthma affects an estimated 300 million people and COPD [an estimated 210 million], so it’s only natural for some patients to have a combination of both diseases. This category of patients constitutes the ACOS group.

You may ask why it is important to even acknowledge ACO. First, there are not many studies looking specifically at this population. The information we have so far is extrapolated from data obtained from asthma and COPD studies where the patients with this overlap have been excluded.