Asthma, a priority for the allergist
Authors: M. Humbert
Journal: Allergy (2006)

Asthma is one of the most common chronic diseases in the world. A recent statement from the Global Initiative for Asthma (GINA) programme published in Allergy has summarized the current knowledge on the burden of asthma (1). Around 300 million people in the world currently have asthma and this condition has become more common in both children and adults in recent decades. Importantly, as the rate of asthma increases as communities adopt western lifestyle and become urbanized, it is estimated that there may be an additional 100 million more asthmatics by 2025 (1). On a more dramatic note, it is estimated that asthma accounts for about one in 250 deaths worldwide, many of which being preventable and explained by suboptimal long-term care and delay in obtaining help during the final attack (1). Thus, the burden of asthma in many countries is of sufficient magnitude to warrant its recognition as a priority disorder in government health strategies. Importantly, the European Union gave a high priority to asthma research with the recognition and funding of the Network of Excellence Global Allergy and Asthma European Network (GA2LEN) (2). The economic cost of asthma is considerable both in terms of direct medical costs (drugs, hospitalization) and indirect medical costs (time lost from work and premature death). The number of disability-adjusted life years (DALYs) lost due to asthma worldwide is currently estimated about 15 million/year, and asthma accounts for around 1% of all DALYs lost, reflecting the high prevalence and severity of asthma (1). These dramatic numbers are in sharp contrast with the considerable progresses made in recent years in asthma research with the development of potent asthma therapies and a better identification of preventable factors that trigger exacerbations of asthma. It thus appeared timely to the Allergy editors to gather several original articles and reviews on asthma in a single issue of our Journal. Inhaled corticosteroids (ICS) are the cornerstone of persistent asthma controller therapy and treatment strategies of persistent asthma based on the use of ICS have been associated with major improvements in asthma outcomes (3). Several novel ICS are currently in development with the aim of being both more convenient (for instance once daily dosage) and better tolerated (with a reduction of local oropharyngeal and systemic side-effects) while maintaining efficacy (4). It is widely accepted that novel ICS with a better tolerability profile are still needed. The review article by Buhl on local oropharyngeal side-effects of ICSs in patients with asthma, clearly highlights recent improvements in ICS therapy (5). In addition, novel data by Wilson et al. on anti-inflammatory effects of once daily low dose inhaled ciclesonide in asthmatic patients are of great interest (6). Finally, the effects of complementary treatments have to be tested in asthma. Hedman et al. have assessed the effect of salt chamber treatment as an add-on therapy to low to moderate ICS in asthma patients with bronchial hyperresponsiveness (7). Indeed, salt chamber treatment reduced bronchial hyperresponsiveness as an add-on therapy in asthmatics treated with a low to moderate dose of ICS, indicating that salt chamber treatment may serve as a complementary therapy to conventional therapy (7). Asthma control is a major objective of asthma management (8). Obviously, ICS allows asthma control in a majority of mild asthmatics. In moderate to severe asthma add-on therapies (including long-acting β-2 agonists, theophylline and leucotriene antagonists) are necessary to improve asthma control. Among those, formoterol and salmeterol represent a major input to asthma pharmacotherapy and development of fixed combination therapies has been extremely helpful. The Gaining Optimal Asthma Control (GOAL) study has previously shown the superiority of salmeterol/fluticasone dipropionate compared with fluticasone dipropionate alone in terms of improving guideline-defined asthma control (8). In the present issue of Allergy, Briggs et al. demonstrate that this improvement in control is associated with cost-per-QALY figures that compare favourably with other uses of scarce healthcare resources (9). In severe allergic asthmatics having poor disease control and frequent exacerbations despite best standard of care (including high doses ICS, long-acting β-agonists and other controller therapy if needed) recent articles published in Allergy have shown the effects of omalizumab, an anti-immunoglobulin E monoclonal antibody, to improve asthma control and reduce the number of asthma exacerbations (10-12). Similarly, pharmacoeconomy data will be needed in this subset of omalizumab-treated severe asthmatics. Recent developments in asthma therapy have been derived from a very active research. Release of novel information in this issue of Allergy on asthma epidemiology and genetics will be of interest to the allergy specialists. Childhood is known to be the most important time for asthma development. Bjerg et al. have studied changes in asthma and wheeze, remission of asthma, and changes in risk factor pattern from age 7–8 to age 11–12 years in northern Sweden (13). They showed that the prevalence of asthma increased continuously during the primary school ages, and was largely determined by allergic sensitization and asthma severity, although the risk factor pattern is obviously complex (13). Grize et al. analysed changes in prevalence rates of asthma, allergic rhinitis and atopic dermatitis in 5–7-year-old Swiss children from 1992 to 2001 (14). These data on four consecutive surveys suggest that the increase in prevalence of asthma and hay fever in 5–7-year-old children living in Switzerland may have ceased (14). Exposure to various airborne agents is associated with asthma symptoms. In this issue of Allergy, a report by Willers et al. suggest that gas cooking per se is associated with nasal symptoms and not with the other respiratory and allergy outcomes in children (15). Mamessier et al. show that diesel-exhausted particles enhance T-cell activation in severe asthmatics, with a higher effect during exacerbations (16). These data are in keeping with epidemiological data demonstrating that diesel-exhausted particles trigger respiratory symptoms in asthmatics but not in controls. Finally, Erpenbeck et al. demonstrate significant alterations of all surfactant proteins in bronchoalveolar lavage fluid after allergen challenge of which surfactant protein C was most closely related to surfactant dysfunction and the degree of the allergic inflammation (17). Recent years have witnesses a very active research in allergy and asthma genetics. Asthma genetics is highly complex, about every second candidate gene being not confirmed in consecutive studies. Interestingly, Bierbaum et al. confirmed association of interleukin-15 gene polymorphisms with paediatric asthma (18). In addition, Sanz et al. show that promoter genetic variants of prostanoid DP receptor gene could be associated with asthma (19). Finally, Puthothu and Heinzmann, could not demonstrate an association between polymorphims in toll-like receptor 6 or 10 with bronchial asthma (20). Asthma is by definition variable. It can be mild, intermittent or severe and disabling. Asthma exacerbations are troublesome, irrespective of baseline asthma severity. They may require emergency care and delayed management exposes to dramatic outcomes and deaths. The burden of asthma is obviously very high in our societies and the allergist is exposed daily to asthma patients, some of them difficult to control (21). Despite outstanding advances in research and therapy, asthma will always be a priority for the allergist.