Bronchial Asthma: An Unsolved Health Problem
Enrico Heffler, MD, is a young italian allergist & immunologist, and his main clinical research field is asthma and its comorbidity. Enrico is the current Junior Member representative for asthma section board of European Academy of Allergology and Clinical Immunology (EAACI), and the current national coordinator of Junior Members of Italian Society of Allergology and Clinical Immunology (SIAIC).
Enrico, which is the current prevalence of asthma and which is the predictable trend of it for the next decades?
Asthma is one of the most common chronic diseases in the world: its global prevalence is estimated about 1-18% of the population, depending on the considered country. Around 300 million people in the world currently have asthma and probably there is still a large proportion of asthmatic patients, particularly in low income countries, who are not included in this estimate because they are not properly diagnosed.
In the last decades, the worldwide prevalence of asthma dramatically increased both in children and adults, similar to what happened to other allergic diseases such as rhinitis or eczema, in parallel with an increase in atopic sensitisation which seems to be somehow related to western lifestyle and to urbanisation. It is estimated that in 2025 about 60% of the whole world’s population will live in urban settings and that will be probably accompanied with a further increase of about 100 million people suffering for asthma in the next 15 years.
Is there any difference in prevalence and impact of asthma in different countries?
There is now evidence that there is a progressive increase of asthma symptoms prevalence in regions where prevalence was previously low, such as Africa, South America and some regions of Asia, while the prevalence decreases in North America and Western Europe. The result of these different trends in prevalence of asthma is that, despite the fact that international differences are lessening, the global burden of asthma is continuing to rise, particularly in countries in which patients may have difficulties to access to basic asthma medication or medical care.
Hence, disadvantaged countries are now experiencing an increase of need of asthma medications and cures, but without enough resources to face this emerging clinical problem; in these countries it is particularly troublesome to correctly treat patients with more severe asthma.
As happens for several other diseases, the economic condition of a country deeply influences the way asthma is diagnosed and treated; increasing the economic wealth and improving the distribution of resources between and within countries should represent important priorities to enable better health care to be provided.
Do people still die from asthma?
Yes they do! It is estimated that asthma accounts for about 1 in every 250 deaths worldwide, with the highest rates of disease-related mortality in China and Russia (36.7 and 28.6 asthma death per 100,000 asthmatics, respectively), Uzbekistan (27.2), Albania (20.8) and South Africa (18.5).
Many of these deaths could be largely preventable improving long-term medical care, giving the opportunity to all patients to access to basic medications, promoting prevention campaigns and reducing the delay in obtaining help during the final attack.
Which is the public health impact/cost for asthma?
The economic cost of asthma is considerable both in terms of direct medical costs (such as costs of medications used to prevent and treat asthma, hospital admissions etc.) and indirect medical costs (such as time lost from work and school, and premature death). As far as costs and disease-related disability, asthma impacts on health-related costs similarly to other chronic diseases such as diabetes, liver cirrhosis or schizophrenia, leading scientific societies, health-care systems and governments to look for the right way to better prevent, diagnose and treat such an impacting disease.
How can we reduce the impact and cost of asthma?
First of all, it is fundamental that governments and health-professionals recognise asthma as an important cause of morbidity and mortality worldwide, so that they can put to use all preventative measures in order to reduce the morbidity and better control symptoms of asthma. Particularly, it is important to reduce environmental factors (such as indoor and outdoor pollution) which may affect respiratory morbidity: promoting anti-tobacco public health policies and reducing occupational exposures may be good starting points!
Since it is acknowledged worldwide that prevalence and economic/health impact of chronic diseases are more elevated where there are poverty, poor education and poor infrastructures, it is fundamental to improve accessibility to essential drugs and medical care for the management of asthma to all social classes and to low- and middle-income countries, also by adapting international asthma guidelines for developing countries to ensure they are practical and realistic in terms of different health care systems.
What is, in your opinion, the major unmet need in asthma management?
The main asthma-related problem that scientific community should find the way to solve is, in my opinion, that about 10% of the patients have a severe form of asthma, characterized by a particular resistance to typical treatment modalities, including administration of high dose of inhaled or systemic corticosteroids and high dose of bronchodilators. This severe end of the disease spectrum accounts for approximately 30% of health care costs of asthma. Thus there is a compelling need to look for new therapeutical tools for patients resistant to typical asthma medications. Different strategies, almost all of them targeting specific different phenotypes of severe asthma, have been proposed, but only few of them are currently used and suggested for severe asthmatics. Omalizumab (an anti-IgE monoclonal antibody) has been recently introduced in clinical practice and it showed to be greatly effective for the treatment of severe allergic asthmatics with high levels of serum IgE. Other therapeutical approaches that have been studied in the last decade include anti-Tumor Necrosis Factor alpha (anti-TNFα) strategies (biological agents against TNFα axis unfortunately gave contrasting results in improving severe asthma outcomes), anti-IL5 drugs (recently Mepolizumab, an anti-IL5 monoclonal antibody has been showed to be effective in reducing severe exacerbations and to improve disease-related quality of life in a particular subset of patients: those with refractory eosinophilic asthma), anti-IL2 biological agents (Daclizumab, a humanized monoclonal antibody against the IL-2R alpha chain, has been recently described to improve pulmonary function and asthma control in patients with moderate to severe chronic asthma inadequately controlled on inhaled corticosteroids), and even interventions to decrease airway smooth muscle, such as bronchial thermoplasty (a bronchoscopic procedure in which controlled thermal energy is applied to the airway wall). Unfortunately, apart from Omalizumab, none of these novel thereapeutical modalities are currently available and recommended to treat patients with severe asthma.
Thus, it is to be hoped that the scientific community focuses the attention on novel and possibly affordable treatments for those asthmatic patients who still are at-risk of severe exacerbations, hospital admissions and death
Savino Sciascia is a TLS RA and an intern at the University of Turin
sciascia.savino@gmail.com