An update on the pharmacological treatment of asthma
In conjunction with World Asthma Day which falls on 3rd May 2016,
MIMS Doctor speaks to a renowned respiratory medicine specialistDato' Dr. Hj Abdul Razak Abdul Muttalif, regarding the chronic airway disease.
Q: What is the burden of asthma in Malaysia?
A: An estimated 4 to 6 percent of adults and 10 to 12 percent of children in the country suffer from asthma. The disease appears to be on an upward trend and I see increasingly more patients with asthma coming into my clinic. This may be due to changes in diet and environment, such as worsening air pollution. Moreover, asthma is not well recognized as some patients present with only chronic cough, which may be wrongly diagnosed as chest infections.
Q: So how do you ensure a correct diagnosis of asthma?
A: To accurately diagnose asthma, comprehensive history taking is necessary. Ask for patient history of eczema or rhinitis. Also, check for any family history of asthma or eczema. Then, ask the patient about his symptoms and auscultate his lungs for wheezing, among other necessary examinations. There are three diagnostic tests that can be used to diagnose asthma. The spirometry test is the most commonly used diagnostic test. It is able to detect airway obstruction and determine if it’s reversible. As such, it can distinguish asthma from chronic obstructive pulmonary disease (COPD), a popular differential diagnosis of asthma. Another diagnostic test is the exhaled nitric oxide test, which can assess airway inflammation. Generally, it is not a common practice to perform this test because it is expensive. The third test is the methacholine challenge test, which measures the airway responsiveness. Airway hyperresponsiveness is a feature that may contribute to a diagnosis of asthma.
Q: What are the challenges of asthma management?
A: In MOH clinics and hospitals, basic asthma medications such as bronchodilators and corticosteroid inhalers are widely available. Moreover, MOH medical centres that are not well-equipped to manage patients with poorly controlled asthma have the option of referring patients to chest physicians or bigger hospitals. On the other hand, the private sector may not be able to manage asthma patients optimally due to cost limitations, and this may lead to poorly controlled asthma.
Q: What are the goals of asthma management?
A: The goals of asthma management are to ensure patients get to live a normal life and to prevent exacerbations. Most physicians refer to the Global Initiative for Asthma (GINA) Guidelines for the management of asthma, which has a treatment algorithm arranged stepwise for easier referencing in the latest 2015 edition. In step 1, a patient with asthma is started on a β2-agonist. If their asthma is not well controlled, they will be moved to step 2 where a low-dose inhaled corticosteroid (ICS) is added to the β2-agonist. In step 3, the options are to either increase the ICS dose or use ICS/LABA. In step 4, either increase the dose of the ICS/LABA or add another drug like theophylline. In step 5, the patient is taking all of these medications plus oral corticosteroid. If the patient still has poorly controlled asthma, bronchothermoplasty is a novel option in step 5. For better understanding of the algorithm, read the GINA guidelines.
Q: Studies in Europe and the Asia-Pacific region have reported an over-utilization of quick-relief medication (ie, short-acting β2-agonists) in asthmatic patients compared with ICS, irrespective of their disease severity. [Eur Respir J 2000;16:802–807, Respirology 2005;10(5):579–586] Can you tell us more about this?
A: The AIRIAP I and II, and REALISE Asia studies showed the use of corticosteroids is very low in the Asia-Pacific region. [Respirology 2005;10(5):579–586, Allergy 2013;68(4):524–530, J Asthma Allergy 2015;8:93–103] The three studies showed only 15 to 20 percent of Malaysians used preventer inhalers—also called ICS—as most do not perceive any immediate effect after its use. Many prefer to take β2-agonists over steroids because the effects are seen within 4 minutes and the symptoms of breathlessness and wheezing are improved quickly. Nevertheless, short-acting β2-agonists provides only short-term relief and patients will get repeated asthma attacks as the effect wears off. The most important inhaler for long-term asthma control and prevention of exacerbations is ICS.
Q: Apart from simplifying treatment regimens, what are the other strategies that could be used by the clinicians to improve patient compliance to asthma treatment?
A: Education. Giving patients the most effective medication is not enough. Patients need to be educated about the respiratory disease, including avoidance of trigger factors and what to do when an exacerbation occurs. They also need to be educated on the types of asthma medication and devices available; potential side effects or interactions with other medications; and importance of compliance. Every patient should have an individually tailored asthma control plan, which will also help improve compliance.