Influence of long-term cigarette smoking on immunoglobulin E-mediated allergy, pulmonary function, and high-resolution computed tomography lung densitometry in elderly patients with asthma

Reliability of Total Serum IgE Levels to Define Type 2 High and Low Asthma Phenotypes

Background: High total IgE levels are weak predictors of T2High and have been reported in nonallergic asthma. Therefore, the role of total serum IgE (IgE) in the T2High phenotype is still debated. Objective: This study investigated the reliability of stratifying asthmatics into IgEHigh and IgELow within the T2High and T2Low phenotypes. Methods: This cross-sectional single-center study investigated the association of clinical, functional, and bio-humoral parameters in a large asthmatic population stratified by IgE ≥ 100 kU/L, allergen sensitization, B-EOS ≥ 300/µL, and FENO ≥ 30 ppb. Results: Combining T2 biomarkers and IgE identifies (1) T2Low-IgELow (15.5%); (2) T2Low-IgEHigh (5.1%); (3) T2High-IgELow (33.6%); and T2High-IgEHigh (45.7%). T2Low-IgELow patients have more frequent cardiovascular and metabolic comorbidities, a higher prevalence of emphysema, and higher LAMA use than the two T2High subgroups. Higher exacerbation rates, rhinitis, and anxiety/depression syndrome characterize the T2Low-IgEHigh phenotype vs. the T2Low-IgELow phenotype. Within the T2High, low IgE was associated with female sex, obesity, and anxiety/depression. Conclusions: High IgE in T2Low patients is associated with a peculiar clinical phenotype, similar to T2High in terms of disease severity and nasal comorbidities, while retaining the T2Low features. IgE may represent an additional biomarker for clustering asthma in both T2High and T2Low phenotypes rather than a predictor of T2High asthma "per se".

Effects of short-term smoking on lung function and airway hyper-responsiveness in young patients with untreated intermittent adult-onset asthma: retrospective cross-sectional study at a primary-tertiary care hospital in Japan

OBJECTIVE

In daily clinical practice, smokers with asthma and with intermittent disease severity are frequently encountered. The effects of short-term smoking on lung function or disease presentation in younger patients with intermittent adult-onset asthma remain unclear. We sought to clarify the effects of short-term smoking (<10 pack-years) on lung function and airway hyper-responsiveness (AHR) in young patients with untreated intermittent adult-onset asthma.

DESIGN

Retrospective, cross-sectional study.

SETTING

A single primary-tertiary medical centre in Japan.

PARTICIPANTS

From patients who underwent bronchodilator reversibility tests between January 2004 and March 2011 (n=7291), 262 consecutive patients (age, 20-34 years) with untreated intermittent adult-onset asthma, including 157 never smokers and 105 current smokers within 10 pack-years, were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the association of the daily smoking frequency (number of cigarettes per day), smoking duration (years) and cumulative smoking history (pack-years) with postbronchodilator lung function. The secondary outcome was the association of the former three smoking parameters with AHR.

RESULTS

The daily smoking frequency, smoking duration and cumulative smoking history were significantly associated with decreased postbronchodilator lung function. Daily smoking of ≥11 cigarettes per day was also associated with marked AHR (OR 2.23; 95% CI 1.03 to 4.80), even after adjustment for age, sex, disease duration and body mass index.

CONCLUSION

Short-term active smoking in early adulthood may be associated with decreased lung function and AHR, even in patients with intermittent adult-onset asthma. Our findings suggest a benefit of never smoking, even for young patients with intermittent adult-onset asthma.

Quantitative computed tomography measurements of emphysema for diagnosing asthma-chronic obstructive pulmonary disease overlap syndrome

Background

The diagnostic criteria of asthma–COPD overlap syndrome (ACOS) are controversial. Emphysema is characteristic of COPD and usually does not exist in typical asthma patients. Emphysema in patients with asthma suggests the coexistence of COPD. Quantitative computed tomography (CT) allows repeated evaluation of emphysema noninvasively. We investigated the value of quantitative CT measurements of emphysema in the diagnosis of ACOS.

Methods

This study included 404 participants; 151 asthma patients, 125 COPD patients, and 128 normal control subjects. All the participants underwent pulmonary function tests and a high-resolution CT scan. Emphysema measurements were taken with an Airway Inspector software. The asthma patients were divided into high and low emphysema index (EI) groups based on the percentage of low attenuation areas less than −950 Hounsfield units. The characteristics of asthma patients with high EI were compared with those having low EI or COPD.

Results

The normal value of percentage of low attenuation areas less than −950 Hounsfield units in Chinese aged >40 years was 2.79%±2.37%. COPD patients indicated more severe emphysema and more upper-zone-predominant distribution of emphysema than asthma patients or controls. Thirty-two (21.2%) of the 151 asthma patients had high EI. Compared with asthma patients with low EI, those with high EI were significantly older, more likely to be male, had more pack-years of smoking, had more upper-zone-predominant distribution of emphysema, and had greater airflow limitation. There were no significant differences in sex ratios, pack-years of smoking, airflow limitation, or emphysema distribution between asthma patients with high EI and COPD patients. A greater number of acute exacerbations were seen in asthma patients with high EI compared with those with low EI or COPD.

Conclusion

Asthma patients with high EI fulfill the features of ACOS, as described in the Global Initiative for Asthma and Global Initiative for Chronic Obstructive Lung Disease guidelines. Quantitative CT measurements of emphysema may help in diagnosing ACOS.

Gaining the Upper Hand on Pulmonary Drug Delivery

Asthma, Chronic Obstructive Pulmonary Disease (COPD) and Cystic Fibrosis (CF) are all pulmonary diseases which are characterized by chronic inflammation and an increase in mucus production. Excess mucus in the airways correlates with pathophysiology such as a decline in lung function and prolonged bacterial infections. New drugs to treat these chronic respiratory diseases are currently being developed and include both inhaled and orally administered compounds. Whilst oral drugs may be easier to administer, they are more prone to side-effects due to higher bioavailability. Inhaled compounds may show reduced bioavailability, but face their own unique challenges. For example, thick mucus in the respiratory tracts of asthma, CF and COPD patients can act as a physical barrier that impedes drug delivery. Mucus also contains a high number of enzymes and proteases that may degrade compounds before they reach their site of action. Furthermore, some classes of drugs are rapidly absorbed across the respiratory epithelia into systemic circulation, which may limit their duration of action and/or cause off-target effects. This review discusses some of the different treatment options that are currently available and the considerations that need to be taken into account to produce new therapies for the treatment of chronic respiratory diseases.

Influences of smoking and aging on allergic airway inflammation in asthma

Asthma is a heterogeneous disease with varying phenotypes and numerous risk factors. This condition results from complex interactions between genetic and environmental factors, and active smoking is one of these risk factors. The effects of aging should also be taken into account in these interactions. From an epidemiological standpoint, smokers and/or elderly patients with asthma are not small part in the total population with asthma. Furthermore, both smoking and aging are important risk factors for severe asthma. This review discusses the potential effects of smoking and aging on healthy subjects and patients with asthma, particularly from the perspective of inflammatory changes. First we show evidence that smokers and the elderly have increased neutrophil counts in their airways, which may have impacts on their clinical characteristics of elderly smokers with asthma. Secondly, on the basis of our recent findings on the interactions between smoking and aging in patients with asthma, we propose that IgE/eosinophilic inflammation should not be underestimated in elderly smokers with asthma, particularly those who are atopic. This review may expand our understanding of the effects of smoking and aging on asthma with a new perspective of an old issue.

Airway disease: similarities and differences between asthma, COPD and bronchiectasis

Airway diseases are highly prevalent worldwide; however, the prevalence of these diseases is underestimated. Although these diseases present several common characteristics, they have different clinical outcomes. The differentiation between asthma, chronic obstructive pulmonary disease and bronchiectasis in the early stage of disease is extremely important for the adoption of appropriate therapeutic measures. However, because of the high prevalence of these diseases and the common pathophysiological pathways, some patients with different diseases may present with similar symptoms. The objective of this review is to highlight the similarities and differences between these diseases in terms of the risk factors, pathophysiology, symptoms, diagnosis and treatment.

Smoking and nonsmoking asthma: differences in clinical outcome and pathogenesis

Cigarette smoking in asthma is frequently present and is associated with worsening of symptoms, accelerated lung-function decline, a higher frequency of hospital admissions, a higher degree of asthma severity, poorer asthma control and reduced responsiveness to corticosteroids. Furthermore, it is associated with reduced numbers of eosinophils and higher numbers of mast cells in the submucosa of the airway wall. Airway remodeling is increased as evidenced by increased epithelial thickness and goblet cell hyperplasia in smoking asthmatics. The pathogenesis responsible for smoking-induced changes in airway inflammation and remodeling in asthma is complex and largely unknown. The underlying mechanism of reduced corticosteroid responsiveness is also unknown. This article discusses differences between smoking and nonsmoking asthmatics regarding the clinical expression of asthma, lung function, response to corticosteroids, airway inflammation and remodeling processes. Possible pathogenetic mechanisms that may explain the links between cigarette smoking and changes in the clinical expression of asthma will be discussed, as well as the beneficial effects of smoking cessation.

Pulmonary function tests, sputum induction, and bronchial provocation tests: diagnostic tools in the challenge of distinguishing asthma and COPD phenotypes in clinical practice

BACKGROUND

despite a number of important differences in the pathogenesis, course, and prognosis, asthma and chronic obstructive pulmonary disease (COPD) have many features in common. Furthermore, smoking induces considerable overlap in pathogenesis and clinical features between these conditions. This study aimed to reveal what inflammatory patterns prevail in clinically established diagnosis groups, including overlap phenotypes of asthma and COPD, and to evaluate the correlation with airway reversibility and hyperreactivity in these overlapping conditions.

METHODS

a total of 110 patients (17 healthy subjects; 16 "healthy" smokers; 46 asthma patients: 24 smokers and 22 non-smokers; and 31 COPD patients: 10 COPD patients with reversibility and 21 without) participated in the study. Induced sputum, reversibility testing, methacholine and adenosine 5'monophosphate (AMP) provocation challenges, and skin prick testing were performed. Airways inflammation was assessed by differential cell counts, and cytokines (interleukin-8 [IL-8] and tumor necrosis factor-alpha [TNF-α]) were measured in induced sputum by enzyme-linked immunosorbent assay (ELISA).

RESULTS

COPD patients with reversibility had increased sputum neutrophils, IL-8, and TNF-α levels compared to smoking asthmatics. No difference was found in inflammatory cells and cytokines between COPD subgroups. Sputum neutrophilia was inversely correlated with the change in forced expiratory volume in one second (ΔFEV(1)) in smoking asthmatic patients (r = -0.563, P = 0.036). No correlation was found between airway hyperresponsiveness (AHR), either with methacholine or AMP, and inflammation in asthmatic patients, regardless of smoking. Reversibility was not correlated with inflammation in COPD patients. However, the response to AMP challenge was correlated with sputum neutrophils (r = 0.844, P = 0.001).

CONCLUSION

although overlaps exist in the disease characteristics of asthma and COPD, the combination of lung function testing, sputum induction, and AHR reveals information that facilitates the distinction between these diseases, allowing clinicians to better tailor their therapy.

Complexities of diagnosis and treatment of allergic respiratory disease in the elderly

Atopic diseases such as rhinitis and asthma are relatively common in children and young adults. However, many patients aged >65 years are also affected by these disorders. Indeed, the literature suggests that between 3-12% and 4-13% of individuals in this age range have allergic rhinitis and asthma, respectively. However, these numbers are most likely underestimates because atopic diseases are frequently not considered in older patients. The diagnosis of both allergic rhinitis and asthma in older patients is more difficult than in younger patients because of a wide differential diagnosis of other diseases that can produce similar symptoms and must be excluded. Furthermore, treatment of these disorders is complicated by the potential for drug interactions, concern about the adverse effects of medications, in particular corticosteroids, and the lack of drug trials specifically targeting treatment of older patients with allergic rhinitis and asthma.

Asthma in smokers: challenges and opportunities

PURPOSE OF REVIEW

Cigarette smoking in asthma is associated with poor symptom control and reduced sensitivity to corticosteroids. We summarize recent evidence supporting the adverse effects of smoking in asthma and consider strategies to manage these patients.

RECENT FINDINGS

Smokers have more severe symptoms and are more likely to be admitted to hospital due to poorly controlled asthma compared with nonsmokers with asthma. Possible causes of reduced sensitivity to inhaled corticosteroids in smokers with asthma are noneosinophilic airway inflammation, impaired glucocorticoid receptor function, and/or reduced histone deacetylase activity. Smoking cessation improves asthma control, but quit rates are low. The optimal drug therapy for smokers with asthma is not established due, in part, to the small number of clinical trials performed in these patients. Preliminary data, however, suggest that leukotriene-receptor antagonists may have a beneficial effect in smokers with mild asthma.

SUMMARY

Cigarette smoking in asthma is a risk factor for poor asthma control and reduced sensitivity to corticosteroids. Every effort should be made to encourage individuals with asthma who smoke to quit. Clinical trials are required to identify therapies that restore corticosteroid sensitivity or directly improve symptom control in individuals with asthma who are unable to stop smoking.

Noninvasive evaluation of airway inflammation in asthmatic patients who smoke: implications for application in clinical practice

BACKGROUND

Despite the limited pathological data in asthmatic patients who smoke, it is thought that cigarette smoking may modify airway inflammation.

OBJECTIVES

To summarize the major clinical studies that have used samples obtained by noninvasive techniques, such as blood, urine, exhaled breath condensate (EBC), fractional exhaled nitric oxide (FeNO), and induced sputum, for the evaluation of airway inflammation and the response to treatment in asthmatic patients who smoke and to evaluate which biomarkers have been adequately validated to be used in routine clinical practice.

DATA SOURCES

In this review, we collected the available literature that addressed this topic. We searched the MEDLINE database using a combination of the following keywords: smoking or asthma or inflammation or mechanisms or exhaled nitric oxide or induced sputum or EBC.

STUDY SELECTION

We selected the articles that most adequately addressed this topic for inclusion in this review.

RESULTS

Smoking significantly influences FeNO and negatively affects its concentration, although FeNO can distinguish steroid-naive asthmatic smokers from nonasthmatic smokers. Sputum neutrophilia is the predominant finding in induced sputum in asthmatic patients who smoke but inflammatory mediators derived either from neutrophils or from a T(H)1 response can also be measured in the supernatants. EBC gives the opportunity to evaluate neutrophil-derived cytokines, airway acidification, and plausible protective mechanisms in smoking asthma.

CONCLUSIONS

Despite the encouraging updated results, the introduction of noninvasive techniques in daily clinical practice requires the reworking of some methodologic pitfalls and the identification of a reliable biomarker that is reproducible, possesses normal values, and provides information for the underlying inflammatory process and the response to treatment.

Urban residence is associated with bronchial hyperresponsiveness in Italian general population samples

BACKGROUND

The role of different risk factors for bronchial hyperresponsiveness (BHR), such as gender, atopy, IgE, and environmental factors (smoking, occupational exposure, infections), has been described. Indoor and outdoor pollution play an important role too, but few studies have analyzed the association with BHR. The aim of this study was to assess the effect of urban residence on BHR.

METHODS

We studied two general population samples enrolled in two cross-sectional epidemiological studies performed in Northern Italy (Po Delta, rural area) and Central Italy (Pisa, urban area). We analyzed 2,760 subjects (age range, 8 to 74 years). We performed analysis of variance and logistic regression analysis using ln slope of the dose-response curve of the methacholine challenge test as dependent variable, and sex, age, smoking habits, respiratory symptoms, skin-prick test results, IgE value, residence, and airway caliber as independent variables.

RESULTS

The mean value of ln slope of the dose-response curve adjusted for initial airways caliber (by baseline FEV(1) percentage of predicted value) was significantly higher in female subjects, in smokers, in subjects with respiratory symptoms, in younger and older ages, in subjects with high values of IgE, and in subjects with positive skin-prick test results. After controlling for the independent effects of all these variables, living in urban area was an independent risk factor for having BHR (odds ratio, 1.41; 95% confidence interval, 1.13 to 1.76).

CONCLUSION

Living in urban area is a risk factor for increased bronchial responsiveness.

Effects of 4 months of smoking in mice with ovalbumin-induced airway inflammation

BACKGROUND

The effects of smoking on asthma pathogenesis are complex and not well studied. We have shown recently that 3 weeks of smoking attenuates ovalbumin (OVA)-induced airway inflammation in mice and that 4-6 months of smoking induces emphysema in mice without airway inflammation. Effects of combined long-term smoking and OVA exposure have not been investigated so far.

OBJECTIVE

To study whether long-term smoking affects progression of allergic airway inflammation and/or enhances the development of emphysema in mice.

METHODS

Mice were sensitized to OVA and challenged with saline or OVA aerosols for 6 months. From 2 months onwards, mice were also exposed to air or smoke. Lung tissue was analysed for extent of inflammation, emphysema, remodelling and for cytokine levels, and serum for OVA-specific IgE levels.

RESULTS

Chronic OVA exposure of 6 months resulted in a T helper type 2 (Th2)-type inflammation with increased levels of IL-4, IL-5, IL-6 and infiltration of eosinophils, CD4(+) T cells, macrophages and plasma cells. Smoking induced a Th17-type of airway inflammation, characterized by neutrophils, macrophages, B cells and increased levels of IL-17, IL-6, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor and monocyte chemoattractant protein-1. Concomittant smoking and OVA exposure resulted in inflammation similar to OVA exposure alone. OVA exposure increased IgE levels compared with saline exposure, and smoking did not further increase these levels.

CONCLUSION

We did not find evidence for increased inflammation, IgE levels or emphysema in mice with allergic airway inflammation after 4 months of smoking compared with non-smoking. However, a 4-month exposure to smoke alone did enhance neutrophilic airway inflammation characterized by high pulmonary IL-17 levels. A Th2 inflammatory environment due to OVA exposure may be one explanation as to why no further detrimental effects of smoking on allergic airway inflammation were found.

A brief targeted review of susceptibility factors, environmental exposures, asthma incidence, and recommendations for future asthma incidence research

Relative to research on effects of environmental exposures on exacerbation of existing asthma, little research on incident asthma and environmental exposures has been conducted. However, this research is needed to better devise strategies for the prevention of asthma. The U.S. Environmental Protection Agency (EPA) and National Institute of Environmental Health Sciences held a conference in October 2004 to collaboratively discuss a future research agenda in this area. The first three articles in this mini-monograph summarize the discussion on potential putative environmental exposure; they include an overview of asthma and conclusions of the workshop participants with respect to public health actions that could currently be applied to the problem and research needs to better understand and control the induction and incidence of asthma, the potential role of indoor/outdoor air pollutants in the induction of asthma), and biologics in the induction of asthma. Susceptibility is a key concept in the U.S. EPA "Asthma Research Strategy" document and is associated with the U.S. EPA framework of protecting vulnerable populations from potentially harmful environmental exposures. Genetics, age, and lifestyle (obesity, diet) are major susceptibility factors in the induction of asthma and can interact with environmental exposures either synergistically or antagonistically. Therefore, in this fourth and last article we consider a number of "susceptibility factors" that potentially influence the asthmatic response to environmental exposures and propose a framework for developing research hypotheses regarding the effects of environmental exposures on asthma incidence and induction.

Mainstream cigarette smoke exposure attenuates airway immune inflammatory responses to surrogate and common environmental allergens in mice, despite evidence of increased systemic sensitization

The purpose of this study was to investigate the impact of mainstream cigarette smoke exposure (MTS) on allergic sensitization and the development of allergic inflammatory processes. Using two different experimental murine models of allergic airways inflammation, we present evidence that MTS increased cytokine production by splenocytes in response to OVA and ragweed challenge. Paradoxically, MTS exposure resulted in an overall attenuation of the immune inflammatory response, including a dramatic reduction in the number of eosinophils and activated (CD69+) and Th2-associated (T1ST2+) CD4 T lymphocytes in the lung. Although MTS did not impact circulating levels of OVA-specific IgE and IgG1, we observed a striking reduction in OVA-specific IgG2a production and significantly diminished airway hyperresponsiveness. MTS, therefore, plays a disparate role in the development of allergic responses, inducing a heightened state of allergen-specific sensitization, but dampening local immune inflammatory processes in the lung.

Cigarette Smoke Extract Suppresses Human Dendritic Cell Function Leading to Preferential Induction of Th-2 Priming

Dendritic cells (DC) are key regulators of immune responses. In the current study, we hypothesized that cigarette smoke-induced aberrance in DC function is an important mechanism by which smokers develop cancer, infection, and allergy--diseases common in smokers. We demonstrate that cigarette smoke extract (CSE) inhibits DC-mediated priming of T cells, specifically inhibiting the secretion of IFN-gamma whereas enhancing the production of IL-4 in the MLR. Conditioning with CSE did not effect cytokine (IL-10, IL-6, or IL-12) production from immature DCs, but significantly inhibited IL-12p70 release by LPS-matured DCs. In contrast, IL-10 secretion by LPS-activated CSE-conditioned DCs was enhanced when compared with control DCs. CSE also induced cyclooxygenase-2 protein levels in maturing DCs and significantly augmented endogenous PGE2 release. Conditioning of DCs with CSE also suppressed LPS-mediated induction of CD40, CD80, and CD86, and suppressed maturation-associated CCR7 expression. Although CSE has been reported to induce apoptosis of fibroblasts and epithelial cells, the immunomodulatory effects observed with CSE were not due to diminished DC viability. The effects of CSE on DC function were not exclusively mediated by nicotine, because equivalent, or even higher concentrations of nicotine than those found in CSE, failed to suppress DC-induced T cell priming. These data provide evidence that soluble components extracted from cigarette smoke suppress key DC functions and favor the development of Th-2 immunity.

The use of computed tomography to assess asthma severity

PURPOSE OF REVIEW

Chronic inflammation in asthma can also lead to airway remodeling, which contributes to airway narrowing. It may be possible to assess and quantify the extent of airway remodeling in vivo using computed tomography. This review examines recent developments in the evaluation of asthma severity using computed tomography, and the effect of treatment assessed by computed tomography.

RECENT FINDINGS

Asthma patients have thicker airways on computed tomography scans than do healthy control individuals, and the degree of thickening is related to the severity of disease, airflow obstruction, and airway reactivity. Recent studies have indicated that patients with severe asthma and irreversible airflow obstruction had longer disease duration, a greater inflammatory process and more airway abnormalities, assessed by high-resolution computed tomography, suggestive of airway remodeling. Other studies have shown that high-resolution computed tomography lung density correlates with airflow limitation and lung volume (but not with lung transfer factor), and also correlates with patient age and severity of asthma. More recently, two publications demonstrated the effect of treatment on airway wall thickness and lung density assessed by computed tomography in patients with asthma.

SUMMARY

High-resolution computed tomography is one of the most useful tools for imaging airways and parenchyma. Computed tomography scanning may be useful in determining which patients might benefit from more or less treatment. With additional advances in technology, it is likely that quantitative assessment by computed tomography will ultimately be a valuable tool for the study and treatment of chronic airway diseases.

Are psychiatric disorders associated with worse asthma control and quality of life in asthma patients?

BACKGROUND

Achieving good asthma control has become the major goal of asthma treatment. Studies have reported a high rate of psychiatric disorders among asthma patients, though the impact of these disorders on asthma control and quality of life remains unexplored. This study evaluated the prevalence of psychiatric disorders in 406 adult asthma patients, and associations between psychiatric status, levels of asthma control, and asthma-related quality of life.

METHODS

Consecutive asthma patients presenting to the asthma clinic underwent a brief, structured psychiatric interview, completed the Asthma Control Questionnaire (ACQ) and Asthma Quality of Life Questionnaire (AQLQ), and reported the frequency of bronchodilator use in the past week. All patients underwent standard pulmonary function testing.

RESULTS

A total of 34% (n=136) of patients had one or more psychiatric diagnosis, including major depression (15%), minor depression (5%), dysthymia (4%), panic disorder (12%), generalized anxiety disorder (5%), and social phobia (4%). Though there were no differences in pulmonary function, patients with versus without psychiatric disorders had worse ACQ and AQLQ scores and reported greater bronchodilator use, independent age, sex and asthma severity.

CONCLUSIONS

Results suggest that psychiatric disorders are prevalent among asthmatics and are associated with worse asthma control and quality of life. Physicians should be aware of the potential risk of poorer asthma control and functional impairment in this population.

Overlap of asthma and chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Asthma and chronic obstructive pulmonary disease (COPD) are both defined by the presence of airflow obstruction, but they present distinguishing differences in terms of both risk factors and clinical phenotypes. Yet it is quite common in the clinical setting to observe patients with asthma showing COPD-like phenotypes, and vice versa, making it a priority to search for optimal prevention, treatment, and management strategies for these cases of coexisting lung obstructive diseases.

RECENT FINDINGS

Recent studies have provided further evidence of strong epidemiologic and clinical links between asthma and COPD. Adult subjects with active asthma are as much as 12 times more likely to acquire COPD over time than subjects with no active asthma. Signs identifying patients with asthma predisposed to developing COPD may already be present at the early stages of the disease, a finding with potential implications for prevention of COPD. In addition to spirometry and other pulmonary function tests (such as measurements of residual volume and diffusing capacity of the lung for carbon monoxide), recent evidence suggests that the assessment of type and degree of airway remodeling and the evaluation of inflammatory markers might prove useful in the future to characterize phenotypically patients with coexisting asthma and COPD.

SUMMARY

The nature of the association between asthma and COPD remains unclear and open to discussion. Further research is required to develop effective management algorithms for patients with multiple obstructive lung diseases, determine to what extent early treatment and optimal management of asthma may protect against progression into COPD, and identify genetic markers of individual susceptibility to specific lung disease phenotypes and pharmacologic treatments.