Updated 13 September 2016

What is ACOS and how is it treated?

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When a patient suffers from clinical features of both asthma and COPD (chronic obstructive pulmonary disease) it is referred to as ACOS (asthma-COPD overlap syndrome).

It is not always easy for doctors to distinguish asthma from COPD, particularly in older adults and in smokers.

The symptoms of asthma and COPD

The symptoms can appear to be quite similar. The typical features of asthma include wheezing, shortness of breath, chest tightness and a cough caused by chronic airway inflammation.

The symptoms of COPD include an ongoing mucus-producing cough (a smoker’s cough), shortness of breath, wheezing and chest tightness. Both conditions lead to chronic airflow limitation – in short, it’s difficult to breathe.

Who gets ACOS?

Patients with ACOS are mainly smokers with a history of asthma or non-smokers with long-standing asthma who developed an airflow obstruction that was not reversible.

Prevalence of patients with ACOS have been reported to be between lower than 10% in patients younger than 50, and over 50% in patients older than 80. Prevalence varies according to gender and age.

What treatment is recommended?

Once the condition has been diagnosed, it is recommended that patients be referred for specialised care as outcomes for ACOS are often worse than for COPD or asthma alone.

Studies are ongoing with regards to the most effective treatment for ACOS.


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Asthma Expert

Professor Keertan Dheda has received of several prestigious awards including the 2014 Oppenheimer Award, and has published over 160 peer-reviewed papers and holds 3 patents related to new TB diagnostic or infection control technologies. He serves on the editorial board of the journals PLoS One, the International Journal of Tuberculosis and Lung Disease, American Journal of Respiratory and Critical Medicine, Lancet Respiratory Diseases and Nature Scientific Reports, amongst others.Read his full biography at the University of Cape Town Lung Institute

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