Asthma and chronic obstructive pulmonary disease (COPD) are often confused with each other – but when it comes to treatment, there's a vital difference.

Professor Stephen Lane, Consultant Respiratory Physician at Tallaght Hospital and Peamount Healthcare, says: “Confusion between asthma and COPD is a big issue. Misdiagnosis means treatment may not be effective.”

The National Healthcare Quality Reporting System 2017 report states that in Ireland there are approximately 450,000 people with doctor-diagnosed asthma, and that around 500,000 people aged 40 and over have COPD, but only half are diagnosed..

 

What is the difference?

 

“COPD usually affects people over 40 and the biggest cause is smoking. Asthma, however, can develop at any time of life, and although it is more common in children, it is also very common in adults,” says Lane. Some people have both and this is known as Asthma-COPD overlap (ACO).

“Because of these age profiles, there is a tendency to diagnose older people who have ‘chestiness’ and wheezing with COPD, when in fact they may have asthma (particularly if they have never smoked) – or have both asthma and COPD (ACO),” Lane says.

"There is a tendency to diagnose young people with asthma, and older people with COPD."

Both diseases are commonly treated by inhaled drugs, but whereas in the past both were treated with a combination of an inhaled corticosteroid and a long-acting β2-agonist (LABA), now treatments are tailored to each disease.

For COPD, inhaled corticosteroids are no longer recommended as first-line treatment. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines now recommend bronchodilators as first line treatment, initially a long-acting muscarinic antagonists (LAMA). If necessary, a long-acting β2-agonist (LABA) can be added for more severe cases, where both are commonly packaged together for optimum effect.

For asthma, however, the Global Initiative for Asthma (GINA) guidelines recommend inhaled corticosteroids as the first-line treatment to tackle the inflammation, which is a greater feature of asthma than of COPD.

 

The risks of misdiagnosis

 

“If you use LAMAs and LABAs as first-line treatment for asthma (or combined asthma and COPD), you risk not fully treating the inflammation caused by the asthma,” says Lane. “Hence, early and accurate diagnosis is vital.”

"If you treat COPD with inhaled corticosteroids you are increasing the risk of pneumonia."

To sum up, Lane says: “For a patient with chestiness and wheezing, who is a heavy smoker and over 40, a COPD diagnosis is likely correct. They may also have asthma if they were chesty as a child or have allergies (ACO). COPD is treated with LAMA and LABAs, whereas asthma is treated inhaled corticosteroids in the main. Treating asthma or ACO with LAMA and LABA may worsen the condition and treating COPD with inhaled corticosteroids may cause pneumonia. Thus it is important to get the diagnosis right.”