End of the New Zealand asthma mortality epidemic

Level of Education Modifies Asthma Mortality in Norway and Sweden. The Nordic EpiLung Study

Background and Aim

The relationship between socioeconomic status (SES), asthma and mortality is complex and multifaceted, and it is not established if educational level modifies the association between asthma and mortality. The aim was to study the association between asthma and mortality in Sweden and Norway and to what extent educational level modifies this association.

Participants and Methods

Within the Nordic EpiLung Study, >56,000 individuals aged 30-69 years participated in population-based surveys on asthma and associated risk factors in Sweden and Norway during 2005-2007. Data on educational level and 10-year all-cause mortality were linked by national authorities. The fraction of mortality risk attributable to asthma was calculated, and Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for mortality related to asthma, stratified by educational level.

Results

In total, 5.5% of all deaths was attributed to asthma. When adjusted for potential confounders, the HR for mortality related to asthma was 1.71 (95% CI 1.52-1.93). Those with primary level of education had higher hazard of all-cause death related to asthma than those with tertiary level (HR 1.80, 95% CI 1.48-2.18, vs HR 1.39, 95% CI 0.99-1.95).

Conclusion

Asthma was associated with an overall 71% increased all-cause mortality and 5.5% of deaths can be attributed to asthma. Educational levels modified the risk of mortality associated with asthma, with the highest risk among those with primary education.

Asthma and COPD: A Focus on β-Agonists - Past, Present and Future

Asthma has been recognised as a respiratory disorder for millennia and the focus of targeted drug development for the last 120 years. Asthma is one of the most common chronic non-communicable diseases worldwide. Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality worldwide, is caused by exposure to tobacco smoke and other noxious particles and exerts a substantial economic and social burden. This chapter reviews the development of the treatments of asthma and COPD particularly focussing on the β-agonists, from the isolation of adrenaline, through the development of generations of short- and long-acting β-agonists. It reviews asthma death epidemics, considers the intrinsic efficacy of clinical compounds, and charts the improvement in selectivity and duration of action that has led to our current medications. Important β2-agonist compounds no longer used are considered, including some with additional properties, and how the different pharmacological properties of current β2-agonists underpin their different places in treatment guidelines. Finally, it concludes with a look forward to future developments that could improve the β-agonists still further, including extending their availability to areas of the world with less readily accessible healthcare.

Can GPCRs Be Targeted to Control Inflammation in Asthma?

Historically, the drugs used to manage obstructive lung diseases (OLDs), asthma, and chronic obstructive pulmonary disease (COPD) either (1) directly regulate airway contraction by blocking or relaxing airway smooth muscle (ASM) contraction or (2) indirectly regulate ASM contraction by inhibiting the principal cause of ASM contraction/bronchoconstriction and airway inflammation. To date, these tasks have been respectively assigned to two diverse drug types: agonists/antagonists of G protein-coupled receptors (GPCRs) and inhaled or systemic steroids. These two types of drugs "stay in their lane" with respect to their actions and consequently require the addition of the other drug to effectively manage both inflammation and bronchoconstriction in OLDs. Indeed, it has been speculated that safety issues historically associated with beta-agonist use (beta-agonists activate the beta-2-adrenoceptor (β₂AR) on airway smooth muscle (ASM) to provide bronchoprotection/bronchorelaxation) are a function of pro-inflammatory actions of β₂AR agonism. Recently, however, previously unappreciated roles of various GPCRs on ASM contractility and on airway inflammation have been elucidated, raising the possibility that novel GPCR ligands targeting these GPCRs can be developed as anti-inflammatory therapeutics. Moreover, we now know that many GPCRs can be "tuned" and not just turned "off" or "on" to specifically activate the beneficial therapeutic signaling a receptor can transduce while avoiding detrimental signaling. Thus, the fledging field of biased agonism pharmacology has the potential to turn the β₂AR into an anti-inflammatory facilitator in asthma, possibly reducing or eliminating the need for steroids.

Bitter Taste Receptors in the Airway Cells Functions

G protein-coupled receptors (GPCRs) play a central role in regulating the functions of a diverse range of cell types in the airway. Taste 2 receptor (T2R) family of GPCRs is responsible for the transduction of bitter taste; however, recent studies have demonstrated that different subtypes of T2Rs and key components of T2R signaling are expressed in several extra-oral tissues including airways with many physiological roles. In the lung, expression of T2Rs has been confirmed in multiple airway cell types including airway smooth muscle (ASM) cells, various epithelial cell subtypes, and on both resident and migratory immune cells. Most importantly, activation of T2Rs with a variety of putative agonists elicits unique signaling in ASM and specialized airway epithelial cells resulting in the inhibition of ASM contraction and proliferation, promotion of ciliary motility, and innate immune response in chemosensory airway epithelial cells. Here we discuss the expression of T2Rs and the mechanistic basis of their function in the structural cells of the airways with some useful insights on immune cells in the context of allergic asthma and other upper airway inflammatory disorders. Emphasis on T2R biology and pharmacology in airway cells has an ulterior goal of exploiting T2Rs for therapeutic benefit in obstructive airway diseases.

Pepducins as a potential treatment strategy for asthma and COPD

Current therapies to treat asthma and other airway diseases primarily include anti-inflammatory agents and bronchodilators. Anti-inflammatory agents target trafficking and resident immunocytes and structural cells, while bronchodilators act to prevent or reverse shortening of airway smooth muscle (ASM), the pivotal tissue regulating bronchomotor tone. Advances in our understanding of the biology of G protein-coupled receptors (GPCRs) and biased agonism offers unique opportunities to modulate GPCR function that include the use of pepducins and allosteric modulators. Recent evidence suggests that small molecule inhibitors of Gα_q as well as pepducins targeting G_q-coupled receptors can broadly inhibit contractile agonist-induced ASM function. Given these advances, new therapeutic approaches can be leveraged to diminish the global rise in morbidity and mortality associated with asthma and chronic obstructive pulmonary disease.

Increased Systemic Exposure and Stronger Cardiovascular and Metabolic Adverse Reactions to Fenoterol in Individuals with Heritable OCT1 Deficiency

Fenoterol is a widely used anti-asthmatic and tocolytic agent, but high plasma concentrations of fenoterol may lead to severe and even fatal adverse reactions. We studied whether heritable deficiency of the liver organic cation transporter 1 (OCT1), a trait observed in 3% of Europeans and white Americans, affects fenoterol plasma concentrations and toxicity. OCT1 transported fenoterol with high affinity, and OCT1 inhibition in human hepatocytes reduced fenoterol uptake threefold. After administration of 180 µg of fenoterol to 39 healthy individuals, the OCT1-deficient individuals (zero active OCT1 alleles; n = 5) showed 1.9-fold greater systemic fenoterol exposure (P = 4.0 × 10^-5 ) and 1.7-fold lower volume of distribution (P = 8.0 × 10^-5 ). Correspondingly, the OCT1-deficient individuals had a 1.5-fold stronger increase in heart rate (P = 0.002), a 3.4-fold greater increase in blood glucose (P = 3.0 × 10^-5 ), and significantly lower serum potassium levels. In conclusion, heritable OCT1 deficiency significantly increases plasma concentrations of fenoterol and may be an important factor underlying the excess mortality associated with fenoterol.

Trends in international asthma mortality: analysis of data from the WHO Mortality Database from 46 countries (1993-2012)

BACKGROUND

International time trends in asthma mortality have been strongly affected by changes in management and in particular drug treatments. However, little is known about how asthma mortality has changed over the past decade. In this study, we assessed these international trends.

METHODS

We collated age-standardised country-specific asthma mortality rates in the 5-34 year age group from the online WHO Mortality Database for 46 countries. To be included in the analysis, we specified that a country must have 10 years of complete data in the WHO Mortality Database between 1993 and 2012. In the absence of consistent and accurate asthma prevalence and prescribing data, we chose to use a locally weighted scatter plot smoother (LOESS) curve, weighted by the individual country population in the 5-34-year age group to show the global trends in asthma mortality rates with time.

FINDINGS

Of the 46 countries included in the analysis of asthma mortality, 36 were high-income countries, and 10 were middle-income countries. The LOESS estimate of the global asthma mortality rate was 0·44 deaths per 100 000 people (90% CI 0·39-0·48) in 1993 and 0·19 deaths per 100 000 people (0·18-0·21) in 2006. Despite apparent further reductions in some countries and regions of the world, there was no appreciable change in global asthma mortality rates from 2006 through to 2012, when the LOESS estimate was also 0·19 deaths per 100 000 people (0·16-0·21).

INTERPRETATION

The trend for reduction in global asthma mortality observed since the late 1980s might have stalled, with no appreciable difference in a smoothed LOESS curve of asthma mortality from 2006 to 2012. Although better implementation of established management strategies that have been shown to reduce mortality risk is needed, to achieve a further substantive reduction in global asthma mortality novel strategies will also be required.

FUNDING

The Medical Research Institute of New Zealand, which is supported by Health Research Council of New Zealand Independent Research Organisation.

How Should We Respond to Non-Dominant Healing Practices, the Example of Homeopathy

The debate around the ethics of homeopathy in recent issues of the journal has been approached as a binary question; is homeopathy ethical or not? This paper suggests that this is an unhelpful question and instead discusses a framework to establish the extent to which the dominant (medical) culture should tolerate non-dominant health practices such as homeopathy. This requires a sophisticated understanding of the placebo effect, a critical evaluation of what evidence is available, a consideration of the harm that the non-dominant practice might cause, and a consideration of how this might be affected by the culture of the patient. This is presented as a matter of cultural competence. At a clinical level clinicians need to respect the values and beliefs of their patients and communicate with all the practitioners involved in a patient's care. At a societal level there are a number of factors to be considered when a community decides which practices to tolerate and to what extent.

Pharmacogenomics of long-acting β2-agonists

INTRODUCTION

Long-acting β2-agonists are an effective class of drugs, when combined with inhaled corticosteroids, for reducing symptoms and exacerbations in patients with asthma that is not adequately controlled by inhaled corticosteroids alone. However, because this class of drugs has been associated with severe adverse events, including hospitalization and death in small numbers of patients, efforts to identify a pharmacogenetic profile for patients at risk has been diligently investigated.

AREAS COVERED

The PubMed search engine of the National Library of Medicine was used to identify English-language and non-English language articles published from 1947 to March 2015 pertinent to asthma, pharmacogenomics, and long-acting β2-agonists. Keywords and topics included: asthma, asthma control, long-acting β2-agonists, salmeterol, formoterol, pharmacogenetics, and pharmacogenomics. This strategy was also used for the Cochrane Library Database and CINAHL. Reference types were randomized controlled trials, reviews, and editorials. Additional publications were culled from reference lists. The publications were reviewed by the authors and those most relevant were used to support the topics covered in this review.

EXPERT OPINION

Children, who carry the ADRB2 Arg16Arg genotype, may be at greater risk than adults for severe adverse events. Rare ADRB2 variants appear to provide better clues for identifying the at-risk population of asthmatics.

Nonprescription Epinephrine Metered-Dose Inhaler: To Be or Not To Be

A new product, Epinephrine HFA, is being considered by the Food and Drug Administration (FDA) for marketing approval as a nonprescription bronchodilator inhaler for the treatment of the "temporary relief of mild symptoms of intermittent asthma in adults and children 12 years of age and older." This product would serve as a replacement for Primatene^® Mist, which was removed from the market in December 2011 in accordance with the requirements of the Montreal Protocol to phase out chlorofluorocarbon (CFC) propellants. The Nonprescription Drugs Advisory Committee and the Pulmonary-Allergy Drugs Advisory Committee met in early 2014 to review the clinical data. The data indicate that Epinephrine HFA provides improvement in lung function at the proposed doses and that no clinically important safety issues were observed. There were, however, concerns that the device could malfunction and that the dose-counter could lose accuracy. These device issues are significant for a drug that could be used for life-threatening symptoms of asthma. All study data presented are publically available from the FDA website at www.fda.gov/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/NonprescriptionDrugsAdvisoryCommittee/ucm380890.htm for the February 24, 2014, meeting.

β-Agonist-mediated relaxation of airway smooth muscle is protein kinase A-dependent

Inhaled β-agonists are effective at reversing bronchoconstriction in asthma, but the mechanism by which they exert this effect is unclear and controversial. PKA is the historically accepted effector, although this assumption is made on the basis of associative and not direct evidence. Recent studies have asserted that exchange protein activated by cAMP (Epac), not PKA, mediates the relaxation of airway smooth muscle (ASM) observed with β-agonist treatment. This study aims to clarify the role of PKA in the prorelaxant effects of β-agonists on ASM. Inhibition of PKA activity via expression of the PKI and RevAB peptides results in increased β-agonist-mediated cAMP release, abolishes the inhibitory effect of isoproterenol on histamine-induced intracellular calcium flux, and significantly attenuates histamine-stimulated MLC-20 phosphorylation. Analyses of ASM cell and tissue contraction demonstrate that PKA inhibition eliminates most, if not all, β-agonist-mediated relaxation of contracted smooth muscle. Conversely, Epac knockdown had no effect on the regulation of contraction or procontractile signaling by isoproterenol. These findings suggest that PKA, not Epac, is the predominant and physiologically relevant effector through which β-agonists exert their relaxant effects.

Changing face of β2-adrenergic and muscarinic receptor therapies in asthma

Despite current available treatment options, a significant proportion of patients with asthma remain uncontrolled and asthma pharmacotherapy continues to evolve. β2-Adrenergic receptor agonists play a major role as bronchodilators in asthma therapy, although new perspectives reflect the potential for bias G-protein coupled receptor signaling pathways. Due to the success of muscarinic antagonists in chronic obstructive pulmonary disease, and the elucidation that muscarinic receptors play a role in airway remodeling, muscarinic receptors represent an attractive therapeutic target in asthma. Although short-acting muscarinic antagonists are currently limited to their use in acute asthma and as alternative bronchodilators in individuals who experience side effects with β2-agonists, recent clinical trials indicate that the long-acting muscarinic antagonist, tiotropium, deserves consideration as a potential therapeutic agent for select populations. The continued evolution of anticholinergic therapy in asthma will require appropriately designed studies to assess mechanisms, efficacy and safety in asthma.

GPCRs and arrestins in airways: implications for asthma

The obstructive lung disease asthma is treated by drugs that target, either directly or indirectly, G protein-coupled receptors (GPCRs). GPCRs coupled to Gq are the primary mediators of airway smooth muscle (ASM) contraction and increased airway resistance, whereas the Gs-coupled beta-2-adrenoceptor (β2AR) promotes pro-relaxant signaling in and relaxation of ASM resulting in greater airway patency and reversal of life-threatening bronchoconstriction. In addition, GPCR-mediated functions in other cell types, including airway epithelium and hematopoietic cells, are involved in the control of lung inflammation that causes most asthma. The capacity of arrestins to regulate GPCR signaling, via either control of GPCR desensitization/resensitization or G protein-independent signaling, renders arrestins an intriguing therapeutic target for asthma and other obstructive lung diseases. This review will focus on the potential role of arrestins in those GPCR-mediated airway cell functions that are dysregulated in asthma.

The β-2 agonist debate: is there still a problem?

PURPOSE OF REVIEW

To present an evidence-based review of the US Food and Drug Administration (FDA) recommendations for long-acting β agonist (LABA) use in asthma.

RECENT FINDINGS

The FDA recommendation contraindicating the use of LABAs without a concomitant asthma-controller medication such as an inhaled corticosteroid (ICS) is supported, with the caveat that concomitant use of an asthma-controller medication applies only to ICS therapy and not other asthma controller medications (such as leukotriene receptor antagonist therapy or theophylline). The recommendation that LABA therapy be stopped once asthma control is achieved is restrictive. Although downtitration of therapy should be considered in patients with asthma, who are well controlled, other options such as reducing the dose of ICS may be preferable to stopping LABA therapy. In patients who are at risk of unstable asthma or severe exacerbations, maintaining the ICS/LABA therapy without downtitration may be required. The recommendation against LABA use in patients whose asthma is adequately controlled with a low or medium dose ICS is supported. The recommendation that fixed-dose combination ICS/LABA products should be the only form in which LABAs are prescribed in adolescents and paediatric patients should be extended to all asthma patients.

SUMMARY

The current β agonist debate focuses on the optimal management approaches for the use of LABA therapy to both minimize risk and maximize clinical efficacy.

Chronic treatment in vivo with β-adrenoceptor agonists induces dysfunction of airway β(2) -adrenoceptors and exacerbates lung inflammation in mice

BACKGROUND AND PURPOSE

Inhalation of a β-adrenoceptor agonist (β-agonist) is first-line asthma therapy, used for both prophylaxis against, and acute relief of, bronchoconstriction. However, repeated clinical use of β-agonists leads to impaired bronchoprotection and, in some cases, adverse patient outcomes. Mechanisms underlying this β(2) -adrenoceptor dysfunction are not well understood, due largely to the lack of a comprehensive animal model and the uncertainty as to whether or not bronchorelaxation in mice is mediated by β(2) -adrenoceptors. Thus, we aimed to develop a mouse model that demonstrated functional β-agonist-induced β(2) -adrenoceptor desensitization in the context of allergic inflammatory airway disease.

EXPERIMENTAL APPROACH

We combined chronic allergen exposure with repeated β-agonist inhalation in allergen-treated BALB/C mice and examined the contribution of β(2) -adrenoceptors to albuterol-induced bronchoprotection using FVB/NJ mice with genetic deletion of β(2) -adrenoceptors (KO). Associated inflammatory changes - cytokines (ELISA), cells in bronchoalevolar lavage and airway remodelling (histology) and β(2) -adrenoceptor density (radioligand binding) - were also measured. KEY RESULTS β(2) -Adrenoceptors mediated albuterol-induced bronchoprotection in mice. Chronic treatment with albuterol induced loss of bronchoprotection, associated with exacerbation of the inflammatory components of the asthma phenotype.

CONCLUSIONS AND IMPLICATIONS

This animal model reproduced salient features of human asthma and linked loss of bronchoprotection with airway pathobiology. Accordingly, the model offers an advanced tool for understanding the mechanisms of the effects of chronic β- agonist treatment on β-adrenoceptor function in asthma. Such information may guide the clinical use of β-agonists and provide insight into development of novel β-adrenoceptor ligands for the treatment of asthma.

New perspectives regarding β(2) -adrenoceptor ligands in the treatment of asthma

In the last two decades several significant changes have been proposed in the receptor theory that describes how ligands can interact with G protein-coupled receptors (GPCRs). Here we briefly summarize the evolution of receptor theory and detail recent prominent advances. These include: (i) the existence of spontaneously active GPCRs that are capable of signalling even though they are unoccupied by any ligand; (ii) the discovery of ligands that can inactivate these spontaneously active receptors; (iii) the notion that a ligand may simultaneously activate more than one GPCR signalling pathway; and (iv) the notion that certain ligands may be able to preferentially direct receptor signalling to a specific pathway. Because the data supporting these receptor theory ideas are derived primarily from studies using artificial expression systems, the physiological relevance of these new paradigms remains in question. As a potential example of how these new perspectives in receptor theory relate to drug actions and clinical outcomes, we discuss their relevance to the recent controversy regarding the chronic use of β(2) -adrenoceptor agonists in the treatment of asthma.

Pharmacogenetics of β2 adrenergic receptor gene polymorphisms, long-acting β-agonists and asthma

Adrenergic β2 receptor (ADRβ2) agonists are widely used in asthma. Approximately 10% of patients have severe, poorly controlled disease despite extensive use of ADRβ2 agonists. Variations in responses to ADRβ2 agonists can, in part, be attributed to genetic variation, with 49 different polymorphisms having been identified for the ADRβ2 gene. Although clear associations exist between ADRβ2 gene polymorphisms, such as +46G>A, and patient response, the importance of these polymorphisms remains controversial. Patient selection, the number of polymorphisms analysed, differences in the type/dose of ADRβ2 agonist, use of inhaled corticosteroids and population sizes have all varied. Most studies were limited to mild or moderate asthmatics using ADRβ2 agonists sparingly. It is difficult to extrapolate from these studies to individual patients who have severe asthma, use a variety of ADRβ2 agonists and do so frequently. The extent to which ADRβ2 gene polymorphisms are relevant to asthma management needs further review, both clinically and at the molecular level. In vitro studies have helped to define the functional changes induced by specific ADRβ2 gene polymorphisms, including 3'-untranslated region poly-C repeat. The resulting ADRβ2 gene haplotypes (rather than genotypes), the interactions among ADRβ2 gene haplotypes and variations in the chemistry of different agonists deserve more detailed assessment. Responses to ADRβ2 agonists depend on effective downstream signalling following ADRβ2 activation and also on receptor regulation. Studies on other regulators of ADRβ2 receptor signalling and trafficking may be equally important in understanding the functional role of ADRβ2 gene polymorphisms. The role of ADRβ2 gene polymorphisms in the pathogenesis and management of severe asthma cannot be clearly defined until more specific and targeted research studies are performed.

Safety of formoterol in adults and children with asthma: a meta-analysis

BACKGROUND

The safety of long-acting β2 agonists (LABA) for the treatment of persistent asthma remains a topic of ongoing debate.

OBJECTIVE

To evaluate the risk of serious asthma-related events among patients treated with formoterol, a meta-analysis of all Novartis-sponsored controlled clinical trials was conducted.

METHODS

Forty-five randomized, placebo- and active-controlled, parallel-group or crossover studies with formoterol were included. Background inhaled corticosteroid (ICS) use was permitted in all studies; however, in only 2 studies was ICS randomized as study medication. Sub-analyses of the pooled data were performed according to age (5-12; 13-18; >18 years), baseline ICS use, and lung function. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated between formoterol (twice-daily), albuterol (salbutamol) 4 times per day (active control), and placebo.

RESULTS

Patients were randomized to formoterol (n = 5,367), placebo (n = 2,026), and albuterol (n = 976). Two deaths were reported, 1 each in the formoterol (asthma exacerbation) and the placebo (hemorrhagic pancreatitis) groups. No statistically significant differences in serious asthma exacerbations were observed compared with placebo in adolescents and adults. In children, a higher frequency of hospitalizations was observed among patients treated with formoterol compared with placebo (OR 8.4; 95% CI: 1.1-65.3). A trend toward fewer exacerbations was observed among subjects reporting concomitant ICS use at baseline.

CONCLUSIONS

This analysis supports current guideline recommendations for the use of LABAs only as add-on therapy to ICS.

Asthma in sickle cell disease: implications for treatment

Objective. To review issues related to asthma in sickle cell disease and management strategies. Data Source. A systematic review of pertinent original research publications, reviews, and editorials was undertaken using MEDLlNE, the Cochrane Library databases, and CINAHL from 1947 to November 2010. Search terms were [asthma] and [sickle cell disease]. Additional publications considered relevant to the sickle cell disease population of patients were identified; search terms included [sickle cell disease] combined with [acetaminophen], [pain medications], [vitamin D], [beta agonists], [exhaled nitric oxide], and [corticosteroids]. Results. The reported prevalence of asthma in children with sickle cell disease varies from 2% to approximately 50%. Having asthma increases the risk for developing acute chest syndrome , death, or painful episodes compared to having sickle cell disease without asthma. Asthma and sickle cell may be linked by impaired nitric oxide regulation, excessive production of leukotrienes, insufficient levels of Vitamin D, and exposure to acetaminophen in early life. Treatment of sickle cell patients includes using commonly prescribed asthma medications; specific considerations are suggested to ensure safety in the sickle cell population. Conclusion. Prospective controlled trials of drug treatment for asthma in patients who have both sickle cell disease and asthma are urgently needed.

Global Initiative for Asthma (GINA) guidelines: 15 years of application

The Global Initiative for Asthma (GINA), founded in 1993, embodies a network of public health organizations and medical societies, as well as other individuals concerned with asthma. Its first report, published in 1995 and entitled 'A Global Strategy for Asthma Management and Prevention', has been widely adopted, providing the foundation for asthma guidelines in many nations across the world. To this effect, the report has not only been translated into several languages but has also been frequently updated. Since its establishment 15 years ago, GINA has undergone two major paradigm shifts. The first was the change in the late 1990s from an opinion- to an evidence-based approach for the management of asthma severity. The second, an even more radical shift, was seen in 2006, when the revised GINA guidelines involved the classification of asthma severity according to the level of control as a guide to treatment. In order to classify asthma control, elements such as the significance of the partnership between the patient and caregiver, patient education, guided self-management and treatment goals were introduced. In addition to compiling guidelines and reports for the management of asthma, GINA is actively involved in organizing and coordinating the World Asthma Day, regional initiatives and GINA symposia. On the whole, during the 15 years since their original publication in 1995, the GINA guidelines have provided the basis for many national asthma strategies around the world. This course is most likely to continue in the future. In this paper, the history of the development of the guidelines and other issues regarding the GINA project will be addressed.

Use and safety of long-acting β2-agonists for pediatric asthma

Asthma guidelines recommend the use of long-acting β2-agonists (LABAs) as the preferred add-on therapy for adults and children over 5 years of age when asthma is inadequately controlled by inhaled corticosteroids alone. It has been suggested that LABA use may be associated with an increased risk of morbidity and mortality; however, this view is controversial since study findings have been inconsistent. While the safety profile of LABA monotherapy has been questioned, the value of concomitant inhaled corticosteroids to eliminate possible risks remains unproven. There is a paucity of efficacy and safety data for LABA use in children, and existing evidence is not sufficiently convincing to demonstrate a clear position for LABAs in the management of childhood asthma. The main aims of this article are to place LABAs in context in the management of childhood asthma and evaluate the current evidence for safety and efficacy.

The decrease in asthma-related mortality in France

BACKGROUND

Asthma-related morbidity, mortality and socioeconomic cost represent significant public health problems. Despite efficient therapies, in 1999 asthma still killed around 2000 people in France.

METHODS

This study investigated the changes in asthma-related mortality in metropolitan France between 1980 and 2005 and examined its regional disparities. Annual age- and gender-specific mortality rates for asthma were calculated, as well as age-standardized rates. The change in asthma-related mortality was estimated by the annual average rate of change fitted using a log-linear regression model. Lastly, regional disparities were mapped.

RESULTS

After having levelled off between 1990 and 1995, asthma-related mortality significantly decreased. From 2000 onwards the drop was more rapid in men than in women. The observed decrease was significant only in people over 35. In 2005, there were 1129 deaths due to asthma. Moreover, regional disparities could be seen.

CONCLUSIONS

The decline of asthma-related mortality that started in 1986 continued until 2005. Possible explanations could be better patient care, including the use of inhaled corticosteroids and therapeutic education, and improvement in the recording of deaths.

Inhaled salmeterol and/or fluticasone alters structure/function in a murine model of allergic airways disease

BACKGROUND

The relationship between airway structural changes (remodeling) and airways hyperresponsiveness (AHR) is unclear. Asthma guidelines suggest treating persistent asthma with inhaled corticosteroids and long acting beta-agonists (LABA). We examined the link between physiological function and structural changes following treatment fluticasone and salmeterol separately or in combination in a mouse model of allergic asthma.

METHODS

BALB/c mice were sensitized to intraperitoneal ovalbumin (OVA) followed by six daily inhalation exposures. Treatments included 9 daily nebulized administrations of fluticasone alone (6 mg/ml), salmeterol (3 mg/ml), or the combination fluticasone and salmeterol. Lung impedance was measured following methacholine inhalation challenge. Airway inflammation, epithelial injury, mucus containing cells, and collagen content were assessed 48 hours after OVA challenge. Lungs were imaged using micro-CT.

RESULTS AND DISCUSSION

Treatment of allergic airways disease with fluticasone alone or in combination with salmeterol reduced AHR to approximately naüve levels while salmeterol alone increased elastance by 39% compared to control. Fluticasone alone and fluticasone in combination with salmeterol both reduced inflammation to near naive levels. Mucin containing cells were also reduced with fluticasone and fluticasone in combination with salmeterol.

CONCLUSIONS

Fluticasone alone and in combination with salmeterol reduces airway inflammation and remodeling, but salmeterol alone worsens AHR: and these functional changes are consistent with the concomitant changes in mucus metaplasia.

Beta2-receptor polymorphisms in patients receiving salmeterol with or without fluticasone propionate

RATIONALE

Retrospective pharmacogenetic studies have questioned whether patients with asthma who are arginine homozygous at the beta(2-)adrenergic receptor (position 16) should use long-acting beta-agonists.

OBJECTIVES

To examine whether the response to salmeterol alone or in combination with an inhaled corticosteroid is influenced by beta- receptor polymorphisms.

METHODS

Subjects using only as-needed albuterol were screened and completed two sequential open-label run-in periods (8 wk on as-needed albuterol; 8 wk on as-needed ipratropium). Five hundred forty-four subjects were randomized by Arg16Gly genotype to salmeterol alone or with fluticasone propionate for 16 weeks. Change from baseline in morning peak expiratory flow was the primary endpoint.

MEASUREMENTS AND MAIN RESULTS

Lung function responses were sustained over treatment and no statistically significant changes from baseline between genotypes within treatments were observed. Overall mean changes in morning peak flow for salmeterol with fluticasone propionate were 32.6 L/min (Arg/Arg vs. Gly/Gly, 95% confidence interval [CI], -6.3, 22.1), 25.9 L/min (Arg/Arg vs. Arg/Gly, 95% CI, -7.1, 21.3), and 24.9 L/min (Arg/Gly vs. Gly/Gly, 95% CI, -13.0, 14.6), and for salmeterol alone were 19.4 L/min (Arg/Arg vs. Gly/Gly, 95% CI, -1.7, 21.4), 24.6 L/min (Arg/Arg vs. Arg/Gly, 95% CI, -13.0, 10.6), and 12.4 L/min (Arg/Gly vs. Gly/Gly, 95% CI, -0.2, 22.3) for Arg/Arg, Arg/Gly, and Gly/Gly genotypes, respectively. Other measures of asthma control showed similar responses.

CONCLUSIONS

The results showed no evidence of a pharmacogenetic effect of beta-receptor variation on salmeterol response. Clinical trial registered with www.clinicaltrials.gov (NCT 00102882).

History of guidelines for the diagnosis and management of asthma: from opinion to control

The Global Initiative on Asthma (GINA) was launched in 1993 in collaboration with the National Heart, Lung, and Blood Institute, the National Institutes of Health (USA) and the WHO. Its first effort was the production of a consensus report on asthma treatment, which aimed to bridge the gap between the various treatment options and the incorporation and implementation of innovative treatment forms into daily clinical practice. The first report published in 1995, A Global Strategy for Asthma Management and Prevention, has been translated into several languages, widely adopted and provided the foundation for several asthma guidelines worldwide. The GINA and other guidelines were primarily based on consensus of expert opinion in order to employ a severity-based classification system as a guide to treatment. However, in the late 1990s, guidelines underwent a major paradigm shift from opinion- to evidence-based classification as the foundation for asthma management. A second major shift involved the classification of asthma according to the level of disease control as a guide to treatment, which was realized for the first time in the revised 2006 GINA guidelines. Since their first appearance, asthma guidelines have played a leading role in disseminating information about asthma. In addition, they have had a substantial impact on standardizing asthma care around the world, which is likely to continue in the future. This article addresses the history of guideline development and issues related to asthma guidelines, with particular emphasis on the GINA guidelines.

Asthma mortality and long-acting beta2-agonists in five major European countries, 1994-2004

OBJECTIVES

Over the last few decades, important changes occurred in the pharmacological approach to asthma control. However, the possible link between pharmacologic treatment and asthma death remains controversial.

STUDY DESIGN AND SETTING

Age-standardized asthma mortality rates were computed over the 1994-2004 period for France, Germany, Spain, the UK, and Italy. Rates for children and young adults 5 to 34 years of age, middle age adults 35 to 64 years of age, and elderly adults > or = 65 years. Joinpoint regression was performed to identify years where significant changes in mortality trends occurred. Consumption of inhaled long-acting beta-2-agonists (LABA), including inhaled corticosteroids (ICS) when combined with LABAs in a single inhaler, derived from sales estimates.

RESULTS

In 1994, the highest asthma mortality rates were in Germany (4.7/100,000), and the lowest ones were in Italy and Spain (0.5/100,000). Steady downward trends were observed in all the countries considered. The largest decline was registered in Germany and the smallest one was in the UK. LABA sales increased steadily since 1994, particularly in France, Spain, and the UK, reaching values around 14 Defined Daily Doses (DDD)/1,000 inhabitants in 2004.

CONCLUSION

While the use of LABAs (with or without ICS) increased over the last decade, asthma mortality declined in major western European countries.

International trends in asthma mortality rates in the 5- to 34-year age group: a call for closer surveillance

BACKGROUND

International time trends in asthma mortality have played an important sentinel role in the identification of two epidemics of asthma mortality in some countries in the 1960s and the 1970s and 1980s. Since then, little attention has been paid to the ongoing international time trends.

METHODS

Country-specific data on asthma mortality rates since 1960 in the 5- to 34-year-old age group were collated. To be included in the analysis, countries were required to have data available prior to 1980. A scatter plot smoothing technique was used to model the change in asthma mortality rates with time.

RESULTS

Asthma mortality rates from 20 countries were included in the analysis. An increase in asthma mortality rates was found in the 1960s, with a mean increase of 53% from 0.55 per 100,000 in 1960 and 1961 to a peak of 0.84 in 1966 and 1967. This trend was followed by a progressive decline to a nadir of 0.45 per 100,000 in 1974 and 1975. A gradual increase was then found in asthma mortality rates to a peak of 0.62 per 100,000 in 1985 and 1986, with a mean increase of 38% during this period. Since the late 1980s, there has been a widespread and progressive reduction in mortality rates to a level of 0.23 per 100,000 in 2004 and 2005, with a mean reduction of 63% during this period.

CONCLUSIONS

The widespread increase in asthma mortality in the 1980s and the subsequent, even greater reduction has largely gone unrecognized. We propose that awareness of such trends and their causes is important and that they are investigated contemporaneously.

The beta-agonist saga and its clinical relevance: on and on it goes

The decision by the Food and Drug Administration to issue a "black box" warning for long-acting beta-agonists has been followed by a series of pharmacoepidemiological studies focusing on the safety of these drugs. However, these provide the clinician with mixed messages and do not offer clear guidance as to whether adverse responses to beta-agonists are a relevant consideration in individual patients. Simultaneously, there is a growing body of evidence that continuous or high dose-beta-agonist exposure is proinflammatory and that, paradoxically, airway hyperresponsiveness is enhanced, not attenuated. Also, pharmacological theory regarding the pathophysiological function of the beta-adrenoceptor is having to be revised. A recent clinical study has even suggested that beta-blockers rather than beta-agonists may be beneficial in asthma. In practice, there are individuals in whom excessive beta-agonist use contributes adversely to poor asthma control. The recommendation that concomitant use of inhaled steroids will obviate any risks associated with beta-agonists is not in fact fool-proof. Clinicians need to be aware of how to identify and manage patients for whom beta-agonist treatment is a problem rather than a solution. They constitute a small but important subgroup of patients with difficult asthma.

Pharmacogenetics of asthma

PURPOSE OF REVIEW

Patient response to the asthma drug classes, bronchodilators, inhaled corticosteroids and leukotriene modifiers, are characterized by a large degree of heterogeneity, which is attributable in part to genetic variation. Herein, we review and update the pharmacogenetics and pharmaogenomics of common asthma drugs.

RECENT FINDINGS

Early studies suggest that bronchodilator reversibility and asthma worsening in patients on continuous short-acting and long-acting beta-agonists are related to the Gly16Arg genotype for the ADRB2. More recent studies including genome-wide association studies implicate variants in other genes contribute to bronchodilator response heterogeneity and fail to replicate asthma worsening associated with continuous beta-agonist use. Genetic determinants of the safety of long-acting beta-agonist require further study. Variants in CRHR1, TBX21, and FCER2 contribute to variability in response for lung function, airways responsiveness, and exacerbations in patients taking inhaled corticosteroids. Variants in ALOX5, LTA4H, LTC4S, ABCC1, CYSLTR2, and SLCO2B1 contribute to variability in response to leukotriene modifiers.

SUMMARY

Identification of novel variants that contribute to response heterogeneity supports future studies of single nucleotide polymorphism discovery and include gene expression and genome-wide association studies. Statistical models that predict the genomics of response to asthma drugs will complement single nucleotide polymorphism discovery in moving toward personalized medicine.

[The decrease in asthma-related mortality in France]

INTRODUCTION

Asthma-related morbidity, mortality and socio- economic cost represent significant public health problems. Despite efficient therapies, in 1999 asthma still killed around 2000 people in France.

METHODS

This study investigated the changes in asthma-related mortality in metropolitan France between 1980 and 2005 and examined its regional disparities. Annual age- and gender-specific mortality rates for asthma were calculated, as well as age-standardized rates. The change in asthma-related mortality was estimated by the annual average rate of change fitted using a log-linear regression model. Lastly, regional disparities were mapped.

RESULTS

After having levelled off between 1990 and 1995, asthma- related mortality significantly decreased. From 2000 onwards the drop was more rapid in men than in women. The observed decrease was significant only in people aged more than 35 years. Moreover, regional disparities could be seen.

CONCLUSIONS

The decline of asthma-related mortality that started in 1986 continued until 2005. Potential explanations could be better patient care due to consensus, including the use of inhaled corticosteroids and therapeutic education, and improvement in the recording of deaths.

Pharmacogenetics of the beta 2-adrenergic receptor gene

Asthma is a complex genetic disease with multiple genetic and environmental determinants contributing to the observed variability in response to common antiasthma therapies. One focus of asthma pharmacogenetic research has been the beta2-adrenergic receptor gene (ADR beta 2) and its effect on individual responses to beta agonist therapy. Knowledge about the effects of ADR beta 2 variation on therapeutic responses is evolving and should not alter current Asthma Guideline approaches, which consist of the use of short-acting beta agonists (SABAs) for as-needed symptom-based therapy and the use of a regular long-acting beta agonist (LABA) in combination with inhaled corticosteroid therapy for those asthmatics whose symptoms are not controlled by inhaled corticosteroid alone. These approaches are based upon studies showing a consistent pharmacogenetic response to regular use of SABAs and less consistent findings in studies evaluating LABAs. The emerging pharmacogenetic studies are provocative and should lead to functional studies. Meanwhile, the conflicting data concerning LABAs may be caused by such factors as small sample sizes of study populations and differences in experimental design.

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Asthma mortality in southern Brazil: is there a changing trend?

BACKGROUND

Mortality from asthma increased during the last decades but is now declining in some countries. Little is known about this trend in Brazil.

OBJECTIVE

The objective of the study was to determine the trends in asthma mortality in Southern Brazil.

METHODS

We reviewed death certificates of 566 people in the state of Rio Grande do Sul, Brazil, between 5 and 39 years of age in whom asthma was reported to be the underlying cause of death during the period of 1981-2003. Population data were available in 5-year age groups. Mortality rates were submitted to linear and quadratic regression procedures.

RESULTS

Among children and teenagers (5-19 years), there were 170 asthma deaths, ranging from 4 to 13 deaths each year with rates of 0.154/100,000 to 0.481/100,000. In young adults (20-39 years), 396 asthma deaths occurred, ranging from 9 to 32 each year, with rates from 0.276/100,000 to 1.034/100,000. There was an initial increase in rates, with later stabilization, and then the start of a decline beginning in the late 1990s and the early part of this decade. This trend occurred in both age subgroups examined but was more evident in males.

CONCLUSIONS

Asthma mortality in southern Brazil remains low and appears to be decreasing after reaching a peak in the mid-1990s. The reason for these trends remains unknown.

Respiratory health and lung research in New Zealand

This article summarizes the recent history of respiratory research in New Zealand which was triggered by an epidemic of asthma mortality in the 1980s and which led to the rapid emergence of quality research groups. This unique event led to major initiatives to improve the standards of care for people with asthma in New Zealand. Perspectives on other lung health issues including tobacco control, the COPD epidemic and the emergence of bronchiectasis as a serious respiratory disease are also provided.

Regimen and device compliance: key factors in determining therapeutic outcomes

The two most important differences between inhaled and oral therapy are (1) the lungs have evolved to exclude foreign material while the gut has evolved to take in large amounts of foreign material, and (2) even if patients adhere to a treatment regimen (regimen compliance or adherence), they may fail to derive any benefit from using an inhaler due to failure of drug delivery (poor device compliance). In other words: True compliance = regimen compliance x device compliance. Aerosol scientists, building on the observations of those working in the field of industrial hygiene, have developed devices that largely address the challenge of bypassing the lung's defenses, in that current devices generate aerosols that contain a significant proportion of particles in the range of 1-5 microm. These have a relatively high probability of entering the lungs and depositing through impaction and/or sedimentation. The development of delivery systems for systemically acting drugs has led to further refinement. The second issue, that of patient behavior, has, until very recently, received very little attention from those developing devices. Regimen compliance involves taking the medication at the suggested times. Device compliance (using the device optimally) is dependent on competence and contrivance. A patient taking a tablet before rather than after a meal is likely to receive some therapeutic benefit even if the effect is suboptimal. A patient whose device compliance is poor because either they are not competent to use the device or contrive to use it in an ineffective manner may derive little or no benefit even if they are scrupulously adhering to their treatment regimen. Lack of precision in the use of the terms "compliance" and "adherence" has contributed to the failure to build in features that may help address issues relating to patient behavior. The resurgence of interest in developing devices that can be used to deliver potent systemically acting drugs has, out of necessity, led to the development of systems that help minimize the impact of poor competence or contrivance on drug delivery. There are suggestions, that need to be confirmed, that regimen compliance (adherence) can be influenced by providing feedback. In the absence of formal studies, comparison of the high-tech and low-tech approaches to improving device compliance incorporated into novel devices might provide valuable insights into what aspects of feedback are important in the clinical setting.

Beta-adrenoceptor responses of the airways: for better or worse?

Beta2-adrenoceptor agonists are the first-line treatment of asthma and chronic obstructive pulmonary disease (COPD), in which a short-acting beta2-adrenoceptor agonist is used as required for relief of bronchoconstriction. A long-acting beta2-adrenoceptor agonist may be added to an inhaled corticosteroid as step 3 in the management of chronic asthma. Long-acting beta2-adrenoceptor agonists may also be added in treatment of COPD. This review examines the beneficial and detrimental effects of beta2-adrenoceptor agonists. The beneficial effects of beta2-adrenoceptor agonists are mainly derived from their bronchodilator activity which relieves the bronchiolar narrowing and improves air flow. The potential anti-inflammatory actions of stabilizing mast cell degranulation and release of inflammatory and bronchoconstrictor mediators, is considered. Other potential beneficial responses include improvements in mucociliary clearance and inhibition of extravasation of plasma proteins that is involved in oedema formation in asthma. The side effects of beta2-adrenoceptor agonists are primarily related to beta2-adrenoceptor-mediated responses at sites outside the airways. Of major concern has been the development of tolerance and this is discussed in relation to incidence of increased morbidity and mortality to asthma over the past three decades. A clinical aspect of beta2-adrenoceptor pharmacology in recent years has been the recognition of genetic polymorphism of the receptor and how this affects responses to and tolerance to beta2-adrenoceptor agonists. A controversial feature of beta2-adrenoceptor agonists is their stereoisomerism and whether the inactive (S)-isomer of salbutamol had detrimental actions in the commercially used racemate. The consensus is that despite these adverse properties, beta2-adrenoceptor agonist remains the most useful pharmacological agents in the management of asthma and COPD.

Asthma mortality, inhaled steroids, and changing asthma therapy in Argentina (1990-1999)

BACKGROUND

The asthma managing strategy has evolved and inhaled corticosteroids (ICS) are now the cornerstone of asthma treatment. Their effect on symptoms and exacerbations are well ascertained, whereas their effects on asthma mortality are still matter of debate. This ecological study evaluated asthma mortality rates and drug sales in the decade 1990-1999 in Argentina.

METHODS

Mortality (overall and adjusted for 5-34 years) was obtained from the Argentinean Epidemiological Institute, and data on the sales of antiasthma drugs were provided by the International Marketing Survey.

RESULTS

There was a significant change in drug sales in the spanned period: ICS +479%, inhaled beta2 agonists +32%, theophylline -63%. The crude and adjusted mortality rates were 3.38 and 0.72 in the 1980-1989 decade, and 2.58 (P<0.05) and 0.38 (P<0.01) in the subsequent one. There was inverse correlation between inhaled corticosteroid sale and age-adjusted (5-34) asthma mortality (r=-0.84; P=0.003), and the same with global mortality rates (r=-0.81; P=0.005). A positive correlation was also seen between theophylline sales and mortality.

CONCLUSION

The increased sale of ICS and possibly the decrease of theophylline use seem to be the more relevant factors associated with decreased asthma mortality in Argentina.

Past, present and future--beta2-adrenoceptor agonists in asthma management

The beta-adrenoceptor agonists (beta-agonists) have been used to relieve bronchoconstriction for at least 5000 years. beta-agonists are based on adrenaline and early forms, such as isoprenaline, Lacked bronchial selectivity and had unpleasant side effects. Modern beta-agonists are more selective for the beta2-adrenoceptors (beta2-receptors) located in bronchial smooth muscle and have less cardiotoxicity. Traditional beta2-adrenoceptor agonists (beta2-agonists), such as salbutamol, terbutaline and fenoterol, were characterised by a rapid onset but relatively short duration of action. While valuable as reliever medication, their short duration gave inadequate night-time relief and limited protection from exercise-induced bronchoconstriction. beta2-agonists with longer durations of action, formoterol and salmeterol, were subsequently discovered or developed. When combined with inhaled corticosteroids they improved lung function, and reduced symptoms and exacerbations more than an increased dose of corticosteroids. However, tolerance to the bronchprotective effects of long-acting beta2-agonists and cross-tolerance to the bronchodilator effects of short-acting beta2-agonists is apparent despite use of inhaled corticosteroids. The role of beta2-receptor polymorphisms in the development of tolerance has yet to be fully determined. Formoterol is unique in having both a long-lasting bronchodilator effect (> 12 h) and a fast onset of action (1-3min from inhalation), making it effective both as maintenance and reliever medication. The recent change in classification from short- and long-acting beta2-agonists to rapid-acting and/or long-acting agents reflects the ongoing evolution of beta2-agonist therapy.

How does the quality of care compare in five countries?

International data on quality of medical care allow countries to compare their performance to that of other countries. The Commonwealth Fund International Working Group on Quality Indicators collected data on twenty-one indicators that reflect medical care in Australia, Canada, New Zealand, England, and the United States. The indicators include five-year cancer relative survival rates, thirty-day case-fatality rates after acute myocardial infarction and stroke, breast cancer screening rates, and asthma mortality rates. No country scores consistently the best or worst overall. Each country has at least one area of care where it could learn from international experiences and one area where its experiences could teach others.

Adverse effects of beta-agonists: are they clinically relevant?

Inhaled beta(2)-adrenoceptor agonists (beta(2)-agonists) are the most commonly used asthma medications in many Western countries. Minor adverse effects such as palpitations, tremor, headache and metabolic effects are predictable and dose related. Time series studies suggested an association between the relatively nonselective beta-agonist fenoterol and asthma deaths. Three case-control studies confirmed that among patients prescribed fenoterol, the risk of death was significantly elevated even after controlling for the severity of asthma. The Saskatchewan study not only found an increased risk of death among patients dispensed fenoterol, but also suggested this might be a class effect of beta(2)-agonists. However, in subsequent studies, the long-acting beta(2)-agonist salmeterol was not associated with increased asthma mortality. In a case-control study blood albuterol (salbutamol) concentrations were found to be 2.5 times higher among patients who died of asthma compared with controls. It is speculated that such toxic concentrations could cause tachyarrhythmias under conditions of hypoxia and hypokalemia. The risk of asthma exacerbations and near-fatal attacks may also be increased among patients dispensed fenoterol, but this association may be largely due to confounding by severity. Although salmeterol does not appear to increase the risk of near-fatal attacks, there is a consistent association with the use of nebulized beta(2)-agonists. Nebulized and oral beta(2)-agonists are also associated with an increased risk of cardiovascular death, ischemic heart disease and cardiac failure. Caution should be exercised when first prescribing a beta-agonist for patients with cardiovascular disease. A potential mechanism for adverse effects with regular use of beta(2)-agonists is tachyphylaxis. Tachyphylaxis to the bronchodilator effects of long-acting beta(2)-agonists can occur, but has been consistently demonstrated only for formoterol (eformoterol) a full agonist, rather than salmeterol, a partial agonist. Tachyphylaxis to protection against induced bronchospasm occurs with both full and partial beta(2)-agonists, and probably within a matter of days at most. Underlying airway responsiveness to directly acting bronchoconstricting agents is not increased when the bronchodilator effect of the regular beta(2)-agonist has been allowed to wear off, although there may be an increase in responsiveness to indirectly acting agents. While there has been speculation that underlying airway inflammation in asthma may be made worse by regular use of short-acting beta(2)-agonists, in contradistinction, a number of studies have shown that long-acting beta(2)-agonists have positive anti-inflammatory effects. An Australian Cochrane Airways Group systematic review of the randomized, controlled trials of short-acting beta-agonists found only minimal and clinically unimportant differences between regular use and use as needed. Regular short-acting treatment was better than placebo. However, a subsequent systematic review has found that regular use of long-acting beta-agonists had significant advantages over regular use of short-acting beta-agonists. More studies and data are needed on the regular use of beta(2)-agonists in patients not taking inhaled corticosteroids, and in potentially vulnerable groups, such as the elderly and those with particular genotypes for the beta-receptor, who might be more prone to adverse effects.

Asthma deaths; persistent and preventable mortality

Bronchial asthma remains a significant cause of mortality at all ages, despite the increased understanding of its pathogenesis and the range of drugs available for its treatment. Changes in therapeutic management can influence death rates and constant surveillance, combined with high-quality post mortem investigations, is essential. Disease severity, poor disease management and adverse psychosocial circumstances are all risk factors for asthma mortality. Bronchial asthma causes characteristic histological changes in the mucosa of the airways which are present even before the clinical diagnosis of asthma can be made. These include fibrous thickening of the lamina reticularis of the epithelial basement membrane, smooth muscle hypertrophy and hyperplasia, increased mucosal vascularity and an eosinophil-rich inflammatory cell infiltrate. In addition, mucoid plugging of the airway lumen is frequently associated with fatal asthma. The recognition of these changes can allow the diagnosis of asthma to be made for the first time at autopsy, in those cases where asthma goes undiagnosed in life. Acute severe asthma may be accompanied by pneumothorax and surgical emphysema of the mediastinum. Disorders which may mimic asthma include pulmonary embolism, chronic obstructive pulmonary disease and anaphylaxis, but careful post mortem examination and appropriate investigations should reveal the true cause of death.