Asthma and chronic obstructive pulmonary disease (COPD) are both health conditions involving the respiratory system and can lead to difficulty breathing. There is some overlap between the two conditions and it is estimated that approximately 40% of patients with COPD also suffer from asthma.
However, there are some distinct differences between the two conditions, in their pathophysiology, presentation of symptoms and the optimal management plans. The key differences to aid in diagnosis and treatment decisions are outlined below.
Characteristics of Asthma
Asthma is a chronic inflammatory disorder of the airways that leads recurrent episodes of symptoms such as wheezing, breathlessness, chest tightness and coughing, which commonly occur at night or in the early morning. These flare up periods are associated with triggers that cause obstruction of the airways, which is usually reversible.
Diagnosis of asthma most commonly occurs during childhood, in individuals that have a history of dry cough in the night, although it can present at any age.
Characteristics of COPD
COPD is a disease characterized by the progressive obstruction of the airways that leads to a reduction in airflow and respiratory function. These changes are not completely reversible and inhaled noxious particle or gases, such as cigarette smoke, are associated as risk factors for the condition.
Diagnosis of COPD usually occurs in older adults with a history of smoking or chronic exposure to other inhaled irritants.
Key Differential Factors
Both asthma and COPD are chronic inflammatory diseases of the small airways involving mucus and bronchoconstriction that limit the airflow. However, the differences between the two conditions are important and affect the way we manage them.
The reversibility of the damage to the airways is a major difference between asthma and COPD. The airways obstruction in asthma is largely reversible in patients with asthma, whereas the obstruction in COPD is considered to be irreversible or less reversible.
The difference in reversibility is highlighted in the results from lung function tests, such as spirometry. Both show a reduction in airflow, but assessing the effect of bronchodilator administration can help to differentiate between the conditions. Asthma exhibits greater reversibility and results tend to improve with administration of bronchodilators, whereas COPD shows less improvement with bronchodilator medication.
The classification of severity of asthma and COPD also differs. The severity of asthma is based on the lung function and frequency and severity of symptoms; the severity of COPD is based primarily on the function of the lungs.
Specific Treatment Plans
As the pathology and cause of inflammation are distinct in asthma and COPD, the treatment plan will differ accordingly. While the aim of treatment in asthma is to suppress the chronic inflammation, the main aim in COPD is to reduce symptoms.
There is significant evidence to support the use on anti-inflammatory drugs in patients with asthma to improve symptoms. This is thought to have an effect on the airways by slowing the remodeling that may occur in some patients.
The management of COPD is faced with greater challenges and, at this point in time, there are no medications available that modify the progression of the disease. Instead, managing certain risk factors is thought to be of benefit, such as stopping smoking. Inhaled corticosteroids may help to decrease the frequency of exacerbation in patients with COPD and improve quality of life.