Lung function decline in asthma and early intervention with inhaled corticosteroids

Asthma progression and mortality: the role of inhaled corticosteroids

Overall, asthma mortality rates have declined dramatically in the last 30 years, due to improved diagnosis and to better treatment, particularly in the 1990s following the more widespread use of inhaled corticosteroids (ICSs). The impact of ICS on other long-term outcomes, such as lung function decline, is less certain, in part because the factors associated with these outcomes are incompletely understood. The purpose of this review is to evaluate the effect of pharmacological interventions, particularly ICS, on asthma progression and mortality. Furthermore, we review the potential mechanisms of action of pharmacotherapy on asthma progression and mortality, the effects of ICS on long-term changes in lung function, and the role of ICS in various asthma phenotypes.Overall, there is compelling evidence of the value of ICS in improving asthma control, as measured by improved symptoms, pulmonary function and reduced exacerbations. There is, however, less convincing evidence that ICS prevents the decline in pulmonary function that occurs in some, although not all, patients with asthma. Severe exacerbations are associated with a more rapid decline in pulmonary function, and by reducing the risk of severe exacerbations, it is likely that ICS will, at least partially, prevent this decline. Studies using administrative databases also support an important role for ICS in reducing asthma mortality, but the fact that asthma mortality is, fortunately, an uncommon event makes it highly improbable that this will be demonstrated in prospective trials.

Predicted Values for Spirometry may Underestimate Long-Standing Asthma Severity

Background:

Asthma may show an accelerated lung function decline. Asthmatics, although having FEV₁ and FEV₁/VC (and z-scores) higher than the lower limit of normality, may show a significant FEV₁ decline when compared to previous measurements. We assessed how many asymptomatic long-standing asthmatics (LSA) with normal lung function showed a significant FEV₁ decline when an older FEV₁ was taken as reference point.

Methods:

46 well-controlled LSA (age: 48.8±12.1; 23 females) with normal FEV₁ and FEV₁/VC according to GLI2012 references (FEV₁: 94.8±10.1%, z-score:-0.38±0.79; FEV₁/VC: 79.3±5.2, z-score:-0.15±0.77) were selected. We considered FEV₁ decline, calculated by comparing the latest value to one at least five years older or to the highest predicted value measured at 21 years for females and 23 for males. A FEV₁ decline >15% or 30 ml/years was regarded as pathological.

Results:

When comparing the latest FEV₁ to an at least 5-year-older one (mean 8.1±1.4 years between 2 measurements), 14 subjects (30.4%) showed a FEV₁ decline <5% (mean: -2.2±2.6%), 19 (41.3%) had a FEV₁ 5-15% change (mean: -9.2±2.5%) and 13 (28.3%) a FEV₁ decrease>15% (mean: -18.3±2.4). Subjects with a FEV₁ decline>30 ml/year were 28 (60.8%). When using the highest predicted FEV₁ as reference point and declines were corrected by subtracting the physiological decrease, 6 (13%) patients showed a FEV₁ decline higher than 15%, whereas asthmatics with a FEV₁ loss>30 ml/year were 17 (37%).

Conclusion:

FEV₁ decline calculation may show how severe asthma actually is, avoiding a bronchial obstruction underestimation and a possible under-treatment in lots of apparent “well-controlled” LSA with GLI2012-normal-range lung function values.

Revisiting early intervention in adult asthma

The term "early intervention" with inhaled corticosteroids (ICS) in asthma is used in different ways, thereby causing confusion and misinterpretation of data. We propose that the term should be reserved for start of ICS therapy in patients with a diagnosis of asthma but within a short period of time after the first symptoms, not from the date of diagnosis. Prospective clinical studies suggest a time frame of 2 years for the term "early" from the onset of symptoms to starting anti-inflammatory treatment with ICS. The current literature supports early intervention with ICS for all patients with asthma including patients with mild disease, who often have normal or near-normal lung function. This approach reduces symptoms rapidly and allows patients to achieve early asthma control. Later introduction of ICS therapy may not reduce effectiveness in terms of lung function but delays asthma control and exposes patients to unnecessary morbidity. Results of nationwide intervention programmes support the early use of ICS, as it significantly minimises the disease burden. Acute asthma exacerbations are usually preceded by progressing symptoms and lung function decline over a period of 1-2 weeks. Treatment with an increased dose of ICS together with a rapid- and long-acting inhaled β2-agonist during this phase has reduced the risk of severe exacerbations.

HSP70/CD80 DNA vaccine inhibits airway remodeling by regulating the transcription factors T-bet and GATA-3 in a murine model of chronic asthma

INTRODUCTION

Airway remodeling is an important pathologic feature of chronic asthma. T-bet and GATA-3, the key transcription factors for differentiation toward Th1 and Th2 cells, play an important role in the pathogenesis of airway inflammation, airway hyperresponsiveness and airway remodeling. Previous studies showed that HSP70/CD80 DNA vaccine can reduce airway hyperresponsiveness and airway inflammation in acute asthmatic mice. The present study was designed to determine the effect of HSP70/CD80 DNA vaccine on airway remodeling through regulating the development of Th1/Th2.

MATERIAL AND METHODS

Before being sensitized and challenged by ovalbumin, the BALB/c mice were immunized with DNA vaccine. Lung tissues were assessed by histological examinations. Interferon-γ (IFN-γ)/interleukin-4 (IL-4) levels in bronchoalveolar lavage fluid were determined by ELISA and expressions of IFN-γ, IL-4, T-bet and GATA-3 in spleen were evaluated by real-time polymerase chain reaction.

RESULTS

Chronic asthmatic mice had higher airway hyperresponsiveness, a thicker airway wall, more PAS-positive goblet cells, more subepithelial extracellular matrix deposition and more proliferating airway smooth muscle (ASM)-like cells than control mice (p < 0.05). Compared with the chronic asthmatic mice, the treatment with HSP70/CD80 DNA vaccine could reduce airway hyperreactivity, mucus secretion, subepithelial collagen deposition, and smooth muscle cell proliferation (p < 0.05). DNA vaccination also increased levels of IFN-γ/IL-4 in BAL fluid (p < 0.05), and expression of T-bet/GATA-3 in the spleen (p < 0.05).

CONCLUSIONS

HSP70/CD80 DNA vaccine can inhibit airway remodeling through regulating the development of Th1/Th2 subsets in asthmatic mice.

Could FEV₁ decline have a role in daily clinical practice for asthma monitoring?

OBJECTIVE

The aim of this review was to understand whether FEV1 decline measured during the follow-up of asthmatic subjects (FEV1 variation between two different measurements at a distance of at least 5 years) may have a role in their management.

METHODS

Articles, commentaries and reviews relating to the topic were searched in PubMed.

RESULTS

Patients with an accelerated FEV1 decline (>30 ml/year) may be either steroid-resistant/difficult-to-treat asthmatics or not adequately treated because they are either under-perceivers or poorly adherent to their therapy. Sometimes they may be unable to use devices correctly. Untreated rhinitis and incorrect lifestyle (obesity status, a high-fat diet and lack of exercise) must be considered when facing a pulmonary function decline. Identifying asthmatics with an accelerated FEV1 decline, even with well controlled symptoms, may allow us to make possible treatment adjustments or to remove potentially harmful environmental exposure and suggest a correct lifestyle. Depending on FEV1 decline severity, we may detect different asthma phenotypes. One type is characterized by no/low lung function reduction. Among moderate/severe 'declining' subjects, there may be a group that might be responsive to treatment and a second one with a quicker loss in lung function that may be unresponsive to therapy.

CONCLUSION

FEV1 decline calculation should be assessed early in clinical practice over the course of time in order to make all possible variations in treatment, environmental exposure and lifestyle more efficacious overall for declining subjects responsive to anti-inflammatory therapy. Further studies are necessary to validate this approach to asthma.

The persistence of allergen exposure favors pulmonary function decline in workers with allergic occupational asthma

BACKGROUND

In asthmatics, a rapid decline in pulmonary function is observed, likely as a consequence of airways remodeling. Persistence of allergen exposure in patients with occupational asthma (OA) maintains chronic bronchial inflammation, resulting in a more severe lung function decline. Few studies were performed on the effects of allergen exposure cessation.

OBJECTIVE

This study aims at evaluating the influence of allergen exposure cessation on respiratory decline in allergic asthmatic workers.

METHODS

Two groups of workers with allergic OA were selected. The first group (30 workers) changed job after the diagnosis and was no more exposed to sensitizing allergens, and the second group (28 subjects) did not and, as a consequence of preventive measures in the work place, was exposed to a lower level of allergens. All were treated with conventional therapy, according to GINA protocols. FEV1 changes during a 12-year period were evaluated.

RESULTS

Despite pharmacological therapy, the pulmonary function decay slope was steeper in workers continuously exposed to the sensitizing agent (even at reduced level) than in those with a complete cessation of exposure: final FEV1 loss was 512.5 ± 180 ml versus 332.5 ± 108 ml, respectively. The difference became significant after 4 years from the cessation of the exposure.

CONCLUSIONS

The study shows that the cessation of the exposure to allergen in the work place appears the most effective measure in limiting pulmonary function decline in asthmatic workers and underlines the importance of allergic risk assessment and control in the management of occupational asthma.

Airway remodeling: a potential therapeutic target in asthma

BACKGROUND

Apart from airway inflammation, airway remodeling is one of the main pathological features of asthma. However, it remains unclear when airway remodeling starts in children and whether it could be a potential therapeutic target in asthma.

DATA SOURCES

We have reviewed the recent literature regarding structural changes after airway remodeling, the relationship between airway inflammation and airway remodeling, the relationship between childhood asthma and airway remodeling, and the role of long-term medication in asthma treatment for airway remodeling.

RESULTS

The relationship between airway inflammation and airway remodeling is still controversial. A number of morphological and pathological studies have confirmed that airway remodeling occurs not only in adult asthma, but also in childhood asthma. It develops early in the disease process of asthma. At present, long-term medication in asthma treatment mainly focuses on anti-inflammation. However, there are no therapeutic interventions that revert airway remodeling once it is established.

CONCLUSIONS

Airway remodeling may provide a possible new therapeutic target in the management of asthma. It is imperative to strengthen the research in developing new medications specifically for asthma airway remodeling. Prevention and treatment of airway remodeling become top priority in future asthma research.

Diagnosing asthma in young children: current research & recommendations

Asthma is the leading pediatric chronic illness in the United States, and there has been a steady increase in the incidence of asthma in children younger than 6 years of age. Early intervention for asthma decreases morbidity, controls health care costs, and may even preserve lung function. Asthma is difficult to diagnose in young children and is under-diagnosed in this population. It is important for primary care nurse practitioners to diagnose asthma in young children in a timely manner so that therapy can be initiated. This article reviews current recommendations for diagnosing asthma in young children and highlights new and promising diagnostic tools for asthma.