Exhaled nitric oxide levels correlate with measures of disease control in asthma

The change of FeNO is correlated with asthma control and lung function

Objective

To investigate the changes in fractional exhaled nitric oxide (FeNO) after treatment and the association between FeNO changes and the prognosis and lung function of children with asthma.

Methods

A total of 144 children newly enrolled with non-standardized treatment of asthma were recruited between September 2020 and December 2021. The children were divided into two groups according to the initial FeNO (0 day), and the changes in FeNO after Budesonide/Formoterol Inhalation Powder Mist (B/FIPM) treatment were observed in different subgroups in correlation with future outcomes after 1 year (well controlled or partly controlled) and lung function.

Results

The study showed that B/FIPM therapy significantly reduced FeNO levels and eosinophils (EOS) counts, improving pulmonary function (P < 0.01). FeNO levels significantly decreased in the well controlled group after 1 week treatment but not after 2 weeks. The partly controlled group showed sustained benefits after 2 weeks treatment (P < 0.01). Besides, among the patients with initial FeNO ≤35 ppb, the proportion of well controlled outcome was significantly higher in the group of ΔFeNO >0 (72.73 %) than that in the ΔFeNO ≤0 group (53.85 %) (P = 0.042).

Conclusion

B/FIPM is effective in reducing FeNO levels and EOS counts and restoring lung function in children with asthma. In addition, post-treatment changes in FeNO were predictive of prognosis and correlated with post-treatment lung function.

High fractional exhaled nitric oxide levels in asthma patients: Does size matter?

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is a biomarker for eosinophilic inflammation used for diagnosis and monitoring of asthma. High FeNO indicates significant airway eosinophilia and steroid-responsive airway inflammation. Some children with asthma have extremely high FeNO levels, but whether these levels represent a different asthma phenotype compared with those with mildly elevated FeNO is unclear. The objective of this study is to investigate whether the extent of high FeNO levels correlates with clinical phenotype, asthma control, comorbidity, and pulmonary function test (PFT) findings in children with asthma.

METHODS

Anthropometric data, daytime and nighttime symptoms, controller treatment, comorbidity, and PFT findings were retrieved from the Pediatric Pulmonology Unit database (2014-2020) and correlated with FeNO levels in pediatric asthma patients with high FeNO levels.

RESULTS

Two-hundred children and adolescents with high FeNO levels (range 36-227 ppb) were included. Within this range, higher FeNO levels positively correlated with increased daytime and nighttime symptoms (p = .013 and p = .01, respectively) and poorly controlled asthma (p = .034). A FeNO level of ≥80 ppb was the cutoff for significantly more severe daytime and nighttime symptoms and very poorly controlled asthma compared with levels <80 ppb (p = .004, p = .005, and p = .036, respectively). No correlation was found between FeNO and controller treatment, comorbidity, and PFT performance.

CONCLUSION

In pediatric asthma patients, high FeNO levels correlate with increased symptom severity and poor asthma control. A FeNO level of ≥80 ppb may serve as an objective indicator for severe asthma.

Bronchodilator response and lung function decline: Associations with exhaled nitric oxide with regard to sex and smoking status

Background

Fractional exhaled nitric oxide (FeNO) is a marker of type-2 inflammation used both to support diagnosis of asthma and follow up asthma patients. The associations of FeNO with lung function decline and bronchodilator (BD) response have been studied only scarcely in large populations.

Objectives

To study the association between FeNO and a) retrospective lung function decline over 20 years, and b) lung function response to BD among asthmatic subjects compared with non-asthmatic subjects and with regards to current smoking and sex.

Methods

Longitudinal analyses of previous lung function decline and FeNO level at follow-up and cross-sectional analyses of BD response and FeNO levels in 4257 participants (651 asthmatics) from the European Community Respiratory Health Survey.

Results

Among asthmatic subjects, higher percentage declines of FEV₁ and FEV₁/FVC were associated with higher FeNO levels (p = 0.001 for both) at follow-up. These correlations were found mainly among non-smoking individuals (p = 0.001) and females (p = 0.001) in stratified analyses.

Percentage increase in FEV₁ after BD was positively associated with FeNO levels in non-asthmatic subjects. Further, after stratified for sex and smoking separately, a positive association was seen between FEV₁ and FeNO levels in non-smokers and women, regardless of asthma status.

Conclusions

We found a relationship between elevated FeNO and larger FEV₁ decline over 20 years among subjects with asthma who were non-smokers or women. The association between elevated FeNO levels and larger BD response was found in both non-asthmatic and asthmatic subjects, mainly in women and non-smoking subjects.

Correlations between exhaled nitric oxide, rs28364072 polymorphism of FCER2 gene, asthma control, and inhaled corticosteroid responsiveness in children with asthma

In children with asthma, the responsiveness of inhaled corticosteroids (ICS) is depended on asthma endotype and phenotype. This study aimed to describe the clinical and biological characteristics, and its correlation with polymorphism of rs28364072 in FCER2 of asthmatic children. This work aimed to study the correlation between fractional concentration of exhaled nitric oxide (FE_NO) level and rs28364072 polymorphism of FCER2 gene with ICS responsiveness and disease control in children with asthma. This study was a prospective and descriptive study. All clinical characteristics, FE_NO, blood eosinophil counts (BEC), skin prick test (SPT), total IgE, asthma control test, and FCER2 gene polymorphism were performed for each patient. One hundred and seven asthmatic children who were over 5 years old (9.2 ± 2.6), were included. Patients with FE_NO > 20 ppb had higher percentage of positive SPT, total IgE level, and BEC (89.2 vs 80.0%, 851.1 vs 656.9 UI ml^-1, and 785 ± 576 G L^-1 vs 425 ± 364 G L^-1; respectively). Among them, there were 54.2% of homozygous TT, 36.4% of heterozygous TC, and 9.4% of homozygous CC of rs28364072 polymorphism in FCER2. The percentage of patients with controlled asthma was increasing after 1 month and 3 months (47.1% and 58.8%; respectively). During the study, the ICS was decreasing as indicated by asthma control (348 ± 118 mcg at 1st month vs 329 ± 119 mcg at 3rd month; p < 0.05). CC genotype had the lowest level of increasing FEV1 compared to that in genotype TC and TT (8.4% vs 8.7% and 27.1%; p > 0.05 and p < 0.05; respectively). The percentage of polymorphism in rs28364072 of FCER2 was significant higher in patients with controlled asthma compared to uncontrolled asthma. Asthmatic children with high FE_NO and rs28364072 polymorphism in FCER2 gene are good responders to ICS; however, asthmatic children with homozygous variant CC of rs28364072 are poorly responsive to ICS.

The beneficial role of FeNO in association with GINA guidelines for titration of inhaled corticosteroids in adult asthma: A randomized study

PURPOSE

This study aimed to demonstrate the role of fractional concentration of exhaled nitric oxide (FeNO) in association with Global Initiative for Asthma (GINA) guidelines for treatment of adult patients with asthma.

METHODS

It was a prospective and randomized study. The symptomatic asthmatic patients were randomly divided into two groups: GINA group (followed GINA guidelines; N = 86) or GINA + FeNO group (followed GINA guidelines + FeNO for titration of inhaled corticosteroids - ICS; N = 90). They were followed-up for 9 months.

RESULTS

In GINA group, 37.2% patients had no treatment and 62.8% patients discontinued treatment vs. 40.0% and 60.0% in GINA + FeNO, respectively. After 3, 6 and 9 months of treatment, the percentage of mild, moderate and severe asthma showed no significant difference between the two groups. At 9th month, Δ moderate asthma (reduction) in GINA + FeNO group was significantly higher than in the GINA group (-22.0% vs. -11.6%; P = 0.018). The improvement of asthma control test (ACT) score was not different between the groups at 9th month (12 ± 6 vs. 10 ± 5; P > 0.05); the level of FeNO reduction in GINA + FeNO group was significantly higher than that in GINA group (-42 ± 11 vs. -35 ± 9; P = 0.022). The daily dose of ICS in GINA + FeNO group was significantly lower than that in GINA group (397 ± 171 vs. 482 ± 240 mcg and 375 ± 203 vs. 424 ± 221 mcg; respectively) at the end of 6 and 9 months.

CONCLUSION

The use of FeNO in association with GINA guidelines has a beneficial role for accurate daily dose of ICS in adult patients with asthma.

Study of the role of exhaled nitric oxide (NO) in predicting controlled or uncontrolled asthma in asthmatic children

Background

Exhaled nitric oxide (NO), especially fractional concentration of exhaled NO (FE_NO) has been used to predict the responsiveness to inhaled corticosteroid (ICS) in children with asthma. However, the use of exhaled NO for predicting asthma control in children is still controversial.

Methods

This was a perspective observational study. Asthmatic children who were naïve to inhaled corticosteroid (ICS) were included in the present study. The measurements of FE_NO and CA_NO (concentration of NO in the gas phase of the alveolar), spirometry, blood eosinophil counts (BEC), and total IgE levels were done for each asthmatic child. All study subjects started proper asthma treatment after the enrollment.

Results

Ninety three asthmatic children (9±3 years) with moderate (63.4%) to severe (36.6%) asthma were included and finished the 3-month study. The levels of FE_NO and CA_NO at inclusion were 37±11 ppb and 5.8±1.4 ppb, respectively; the mean of BEC was 617±258 cells/μL; the level of total IgE was 1563±576 UI/mL; 89% of subjects were positive for at least one respiratory allergen. The percentage of severe asthma was reduced significantly after 3 months (P<0.001). Well controlled asthma subjects at 3 months had higher levels of FE_NO and lower levels of CA_NO at inclusion (P<0.05 and P<0.05). FE_NO<20 ppb or CA_NO>5ppb had a risk of uncontrolled asthma at 3 months (OR: 1.7, CI 95% [(0.8) - (3.3)], P<0.05; OR: 1.9, CI 95% [(0.9) - (2.7)], P<0.05; respectively). FE_NO>35 ppb at inclusion had a positive predictive value for asthma control at 3 months (OR: 3.5, CI 95% [2.2-5.9], P<0.01).

Conclusions

Exhaled NO is a biomarker of asthma which may have a potential role to predict the control of asthma in short-term follow up in asthmatic children.

Clinical Utility Of The Exhaled Nitric Oxide (NO) Measurement With Portable Devices In The Management Of Allergic Airway Inflammation And Asthma

Nitric oxide (NO) is a potential bioactive gas produced continuously and constantly in the airways of healthy subjects. In allergic airway inflammation, the level of exhaled NO is usually increased and mediated by inducible nitric oxide synthase (iNOS) enzyme presenting in the epithelium and different inflammatory cells. The measurement of NO concentration in the airway is possible with portable devices which use an electroluminescence technique. In subjects with upper airway with allergic inflammation such as in allergic rhinitis, the measurement of nasal NO (nNO) may help to diagnose and manage the disease. In the lower airway, increased fractional exhaled NO (FENO) reflects directly the inflammatory process that occurs in the airways that are typically seen in asthma. It has been shown that there is a strong correlation between FENO levels and increased activity of airway inflammation mediated by immuno-allergic cells and mediators. Thus, FENO has higher specificity and sensitivity than other methods in diagnosing the severity of inflammation in asthmatic patients. Moreover, the correlation between increased FENO levels and a high risk of bronchial hyperresponsiveness has also been demonstrated. FENO is also a relevant biomarker to evaluate asthma status due to the change of its values occurring earlier than clinical manifestations and spirometry parameters. In addition, the measurement of FENO with portable devices helps to support the diagnosis of asthma, to follow-up the control of asthma and to personalize asthmatic patients for target treatment with biologic therapy. Therefore, measuring FENO with portable devices in the diagnosis and treatment of allergic airway inflammation, especially in asthma, is one of the most essential applications of NO biomarkers in exhaled breath.

Acute Severe Asthma in Adolescent and Adult Patients: Current Perspectives on Assessment and Management

Asthma is a chronic airway inflammatory disease that is associated with variable expiratory flow, variable respiratory symptoms, and exacerbations which sometimes require hospitalization or may be fatal. It is not only patients with severe and poorly controlled asthma that are at risk for an acute severe exacerbation, but this has also been observed in patients with otherwise mild or moderate asthma. This review discusses current aspects on the pathogenesis and pathophysiology of acute severe asthma exacerbations and provides the current perspectives on the management of acute severe asthma attacks in the emergency department and the intensive care unit.

Biomarkers related to respiratory symptoms and lung function in adults with asthma

BACKGROUND

There is a need for easily measurable biomarkers that are able to identify different levels of asthma severity.

AIM

To assess the association between peripheral blood cell counts, fractional nitric oxide in exhaled air (FeNO), urinary biomarkers of oxidative stress (8-hydroxy-2'-deoxyguanosine and 8-isoprostane), and asthma severity in adult patients from the general population.

METHODS

In the Gene Environment Interactions in Respiratory Diseases study, 287 subjects with asthma (aged 20-64) were identified from the general population in Verona (Italy) (2008-2010). Self-reported asthma attacks, asthma-like symptoms and the use of hospital services in the past year were synthesized in a score of respiratory symptoms (SRS). The association of biomarkers with SRS and lung function measures (pre-bronchodilator FEV₁% predicted and FEV₁/FVC) was assessed using quasi-Poisson and Gaussian regression models, respectively.

RESULTS

Eosinophils (ratio of expected scores: RES[95%CI] = 1.19[1.09,1.30]), basophils (RES[95%CI] = 1.24[1.10,1.40]), lymphocytes (RES[95%CI] = 1.27[1.12,1.45]) and FeNO (RES[95%CI] = 1.18[1.02,1.37]) were positively associated with SRS. However, only eosinophils (RES[95%CI] = 1.15[1.02,1.30]) and lymphocytes (RES[95%CI] = 1.25[1.06,1.47]) showed an independent association. Furthermore, eosinophils (change in the expected outcome for 1-SD increase: CEO[95%CI] = -1.18[-2.09, -0.27]%), basophils (CEO[95%CI] = -1.24[-2.16, -0.33]%) and lymphocytes (CEO[95%CI] = -1.07[-1.99, -0.14]%) were individually, but not independently, associated with FEV₁/FVC. Finally, neutrophils were negatively associated with FEV₁% predicted (CEO[95%CI] = -2.22[-4.00, -0.44]%).

CONCLUSIONS

We identified a pattern of association between a set of biomarkers and asthma endotypes in adult patients from the general population, which could improve understanding of the heterogeneity and severity of the disease and could be useful in defining targeted therapeutic approaches.

Severe bronchial asthma in children: a review of novel biomarkers used as predictors of the disease

Severe asthma or therapy-resistant asthma in children is a heterogeneous disease that affects all age-groups. Given its heterogeneity, precision in diagnosis and treatment has become imperative, in order to achieve better outcomes. If one is thus able to identify specific patient phenotypes and endotypes using the appropriate biomarkers, it will assist in providing the patient with more personalized and appropriate treatment. However, there appears to be a huge diagnostic gap in severe asthma, as there is no single test yet that accurately determines disease phenotype. In this paper, we review the published literature on some of these biomarkers and their possible role in bridging this diagnostic gap. We also highlight the cellular and molecular mechanisms involved in severe asthma, in order to show the basis for the novel biomarkers. Some markers useful for monitoring therapy and assessing airway remodeling in the disease are also discussed. A review of the literature was conducted with PubMed to gather baseline data on the subject. The literature search extended to articles published within the last 40 years. Although biomarkers specific to different severe asthma phenotypes have been identified, progress in their utility remains slow, because of several disease mechanisms, the variation of biomarkers at different levels of inflammation, changes in relying on one test over time (eg, from sputum eosinophilia to blood eosinophilia), and the degree of invasive tests required to collect biomarkers, which limits their applicability in clinical settings. In conclusion, several biomarkers remain useful in recognizing various asthma phenotypes. However, due to disease heterogeneity, identification and utilization of ideal and defined biomarkers in severe asthma are still inconclusive. The development of novel serum/sputum-based biomarker panels with enhanced sensitivity and specificity may lead to prompt diagnosis of the disease in the future.

Asthma biomarkers in the age of biologics

The heterogeneous nature of asthma has been understood for decades, but the precise categorization of asthma has taken on new clinical importance in the era of specific biologic therapy. The simple categories of allergic and non-allergic asthma have given way to more precise phenotypes that hint at underlying biologic mechanisms of variable airflow limitation and airways inflammation. Understanding these mechanisms is of particular importance for the approximately 10% of patients with severe asthma. Biomarkers that aid in phenotyping allow physicians to "personalize" treatment with targeted biologic agents. Unfortunately, testing for these biomarkers is not routine in patients whose asthma is refractory to standard therapy. Scientific advances in the recognition of sensitive and specific biomarkers are steadily outpacing the clinical availability of reliable and non-invasive assessment methods designed for the prompt and specific diagnosis, classification, treatment, and monitoring of severe asthma patients. This article provides a practical overview of current biomarkers and testing methods for prompt, effective management of patients with severe asthma that is refractory to standard therapy.

Fractional Exhaled Nitric Oxide for Identification of Uncontrolled Asthma in Children

OBJECTIVE

To determine the utility of Fractional Exhaled Nitric Oxide (FENO) in the identification of uncontrolled asthma in children on therapy, and to identify its cut-off value for determining asthma control.

METHODS

207 children (age 5-15 y) with physician-diagnosed asthma on therapy with at least 12 months follow up were enrolled. Spirometry and FENO measurements were performed. Asthma control was assessed as per GINA guidelines. Sensitivity and specificity of various cut-off values of FENO (15 ppb, 20 ppb, 25 ppb, 30 ppb) for identification of status of control of asthma were calculated.

RESULTS

156 (75%) children had uncontrolled or partly controlled asthma and 51 children were assessed to have controlled asthma. Median (IQR) FENO in children with controlled and uncontrolled asthma was 16 (11-23) ppb and 13 (11-25) ppb, respectively (P=0.26). No FENO cut-off had a reasonable combination of sensitivity and specificity to discriminate between controlled and uncontrolled asthma.

CONCLUSIONS

FENO, in itself, does not have good discriminatory value in assessment of controlled and uncontrolled asthma in children on asthma therapy.

Endothelial nitric oxide synthase gene polymorphisms are associated with sensitization to seasonal aeroallergens in asthmatic children

BACKGROUND

Childhood asthma phenotype is the consequence of interaction between environment and genetic factors. Nitric oxide (NO) formation is affected by polymorphisms in nitric oxide synthase (NOS) enzymes, which play a significant role as inflammatory factors in the airways. This study was undertaken to estimate the correlation of -786C>T and 894G>T polymorphisms of the eNOS gene with the sensitization of asthmatic children to common aeroallergens.

METHODS

A total of 193 asthmatic children and 96 healthy controls, who were of Mediterranean origin, living in the same geographical area, were enrolled in the study. 894G>T and -786T/C polymorphisms of the eNOS gene were analyzed using a PCR-RFLP method.

RESULTS

The 894GG genotype was more frequent (68.6%) in children with asthma sensitized to Oleaeuropaea than in those with asthma non-sensitized (43.0%) (P=0.004). Likewise, -786TT genotype frequency was higher in children with asthma sensitized to Oleaeuropaea (51.0%) than in those with asthma nonsensitized (31.7%) to this allergen (P=0.035). For the aeroallergens Parietariajudaica and mixed grass, the frequency of -786C allele carriage was associated with protection from sensitization to Parietariajudaica and mixed grass in asthmatic children (P=0.021 and P=0.017, respectively). In the healthy control group, the genotype frequencies for these polymorphisms were similar to genotype frequencies of children with asthma non-sensitized to these three specific aeroallergens.

CONCLUSION

In children with asthma, 894G>T and -786T/C polymorphisms of the eNOS gene were correlated with sensitization to common seasonal aeroallergens.

Personalized Medicine in Allergy

Allergic disease is among the most common pathologies worldwide and its prevalence has constantly increased up to the present days, even if according to the most recent data it seems to be slightly slowing down. Allergic disease has not only a high rate of misdiagnosis and therapeutic inefficacy, but represents an enormous, resource-absorbing black hole in respiratory and general medicine. The aim of this paper is to summarize principal therapeutic innovations in atopic disease management befallen in the recent years in terms of personalized/precision medicine.

Clinical Utility of Fractional exhaled Nitric Oxide (FeNO) as a Biomarker to Predict Severity of Disease and Response to Inhaled Corticosteroid (ICS) in Asthma Patients

INTRODUCTION

Bronchial asthma is a common chronic inflammatory airway disease diagnosed and is based on symptomatic history and Pulmonary Function Tests (PFT). Fractional exhaled Nitric Oxide (FeNO) is exclusively a non-invasive biomarker of on-going eosinophilic airway inflammation which remains unpredictable only with PFTs. FeNO measurement is recommended in predicting asthma severity and Inhaled Corticosteroid (ICS) response but further research is required to understand its clinical utility and agreement with current recommendations in a specific population.

AIM

To estimate FeNO levels in Tamilian patients with mild-to-moderate persistent asthma and to correlate with disease severity and ICS response.

MATERIALS AND METHODS

The study was a prospective cohort with a single group of 102 persistent asthma patients under standard ICS regimen for 8 weeks (follow-up period). PFT and FeNO were measured using portable spirometry and chemiluminescence based exhaled breath analyser, at baseline and during follow-up visits. Based on PFT and FeNO parameters, the study population was sub-grouped with respect to asthma severity (as mild, moderate and moderately severe), FeNO cut-off (> or < 50ppb) and ICS response classification (good vs poor ICS responders).

RESULTS

Significant decrease in mean FeNO levels were found in mild, moderate and moderately severe asthmatic groups following ICS treatment (90.15±27.36, 75.74±31.98 and 77.18±32.79 ppb) compared to similar baseline FeNO levels (103.03±34.08, 91.38±37.60 and 97.90±43.84 ppb) in all the above groups. Similarly, significant decrease in mean FeNO levels was found - FeNO>50ppb, good and poor ICS responders groups, in post- ICS treatment (89.63±24.04, 77.90±31.12 and 86.49±32.57 ppb) compared to baseline levels (110.183±1.23, 97.12±42.04 and 99.68±34.71 ppb).

CONCLUSION

The observed baseline FeNO values in all groups as stated above did not show significant difference to differentiate asthma severity or ICS responders groups. The present study results do not support the predictive association of baseline FeNO levels with asthma severity and future ICS response, but the decrements in FeNO levels on ICS treatment, supports its clinical utility in monitoring of ongoing airway inflammation and understanding treatment response rate.

Exhaled nitric oxide in a middle-aged Icelandic population cohort

The prevalence of atopy and asthma is relatively low in Iceland. The purpose of this study was to describe exhaled nitric oxide (FeNO) levels in the general population in correlation with demographic characteristics, smoking status, asthma, rhinitis, atopic status and lung function tests. Altogether 403 subjects, from the European Community Respiratory Health Survey (ECRHS) III who answered the main questionnaire and were checked by FeNO measurements, lung function testing, skin prick testing and measurement of total IgE and specific IgE were included. The geometric mean (95% CI) of FeNO was 16.2 ppb (15.2-17.1) and the prevalence of higher FeNO (⩾25 ppb) was 19.5% in the random sample. Subjects with higher FeNO levels were less likely to be current smokers and more likely to have asthma and rhinitis. Having higher FeNO values was also associated with higher total IgE, having specific IgE to at least one allergen and being skin prick test positive. Current smokers had significantly lower levels of FeNO, geometric mean (95% CI) 9.6 ppb (8.4-11.0), than ex-smokers 18.2 ppb (16.6-20.0) and never smokers 17.3 ppb (16.1-18.5). In multivariable models, having asthma (OR (95% CI) 2.10 (1.20-3.67)), having a specific IgE (OR 2.30 (1.25-4.23)) and being skin prick test positive (OR 2.06 (1.18-3.60)) were independently positively associated with a higher FeNO (⩾25) whereas current smoking was independently negatively associated with a higher FeNO (OR 0.19 (0.06-0.63)). Higher levels of FeNO (⩾25 ppb) were found in one out of five Icelanders; FeNO was positively associated with asthma and allergy and negatively with smoking.

The path to personalized medicine in asthma

INTRODUCTION

Asthma is a common respiratory disorder, since about 10% of the population suffer from this disease, and up to 10% have a severe form. Recent findings have allowed a greater and deeper understanding of the pathophysiological mechanisms, distinguishing two groups of patients according to the prevalent cellular population that drives the inflammatory process, and consequentially, to intervene on different cellular targets.

AREAS COVERED

Currently, several biological drugs directly interfering with these pathophysiological mechanisms (namely IgE, IL-4, IL-5, IL-13, and IL-17) are under investigation. Expert commentary: With the elucidation of mechanisms, new-targeted drugs have been developed. Asthma therapy is changing from a 'one size fits all' therapy to a 'precision medicine' model, where we may prescribe the most appropriate treatment for each patient. Moreover, in the near future, the possibility to act a 'sequential bio-combination therapy' can be envisaged, using different biological drugs in the same patient to act on different pathophysiological mechanisms.

Gastroesophageal dysmotility is associated with the impairment of cough-specific quality of life in patients with cough variant asthma

BACKGROUND

Gastroesophageal reflux disease (GERD) is known as a common comorbidity of asthma and chronic cough. The impact of GERD symptoms on cough-specific quality of life (QoL) in patients with asthmatic cough is poorly understood. The aim of this study is to determine the association of GERD symptoms with cough-specific quality of life in patients with cough variant asthma (CVA) using the Leicester Cough Questionnaire (LCQ).

METHODS

A total of 172 consecutive patients (121 females) with mean cough duration of 45.1 months (range 2-480 months) completed the Japanese version of the LCQ. The Frequency Scale for the Symptoms of Gastroesophageal reflux was administered to assess symptoms of acid-reflux and dysmotility. A range of clinical variables that may determine cough-specific QoL (LCQ) were estimated.

RESULTS

The mean LCQ scores was 12.9 (SD 3.5), consistent with severe impairment in QoL. Female gender, symptoms of gastroesophageal dysmotility, sensitization to allergens (house dust and Japanese cedar pollen) and the number of sensitized allergens were associated with lower LCQ scores (i.e. impaired cough-specific QoL) in univariate regression analysis. Acid-reflux symptoms, airway hyperresponsiveness, fractional exhaled nitric oxide, and sensitization to molds were unrelated to the LCQ score. After adjustment for gender, symptoms of gastroesophageal dysmotility was the only significant determinant of impaired cough-specific QoL accounting for 23% of the variance.

CONCLUSIONS

Cough-specific QoL is severely impaired in patients with CVA. Symptoms of gastroesophageal dysmotility are an independent predictor of cough-specific QoL of patients with CVA.

Is ventilation heterogeneity related to asthma control?

In asthma patients, magnetic resonance imaging (MRI) and the lung clearance index (LCI) have revealed persistent ventilation heterogeneity, although its relationship to asthma control is not well understood. Therefore, our goal was to explore the relationship of MRI ventilation defects and the LCI with asthma control and quality of life in patients with severe, poorly controlled asthma.

18 patients with severe, poorly controlled asthma (mean±sd 46±12 years, six males/12 females) provided written informed consent to an ethics board approved protocol, and underwent spirometry, LCI and 3He MRI during a single 2-h visit. Asthma control and quality of life were evaluated using the Asthma Control Questionnaire (ACQ) and Asthma Quality of Life Questionnaire (AQLQ). Ventilation heterogeneity was quantified using the LCI and 3He MRI ventilation defect percent (VDP).

All participants reported poorly controlled disease (mean±sd ACQ score=2.3±0.9) and highly heterogeneous ventilation (mean±sd VDP=12±11% and LCI=10.5±3.0). While VDP and LCI were strongly correlated (r=0.86, p<0.0001), in a multivariate model that included forced expiratory volume in 1 s, VDP and LCI, VDP was the only independent predictor of asthma control (R2=0.38, p=0.01). There was also a significantly worse VDP, but not LCI in asthma patients with an ACQ score >2 (p=0.04) and AQLQ score <5 (p=0.04), and a trend towards worse VDP (p=0.053), but not LCI in asthma patients reporting ≥1 exacerbation in the past 6 months.

In patients with poorly controlled, severe asthma MRI ventilation, but not LCI was significantly worse in those with worse ACQ and AQLQ.

Diagnosis and investigation in the severe asthma clinic

Severe asthma is recognised as an important and emerging area of unmet need in asthma. The assessment of severe asthma should include three steps; (1) determining the diagnosis of asthma, including verification that the disease is severe asthma, (2) assessing comorbidities and contributing factors that will impact on clinical severity, as well as (3) assessing asthma phenotypes. These steps recognize the importance of heterogeneity in asthma as a key factor that determines the disease course and increasingly the choice of successful therapy. This assessment should be undertaken systematically and is best done by an expert multidisciplinary team. Here, we will outline the important aspects that should be included in the clinical assessment of the patient in the severe asthma clinic, including diagnosis, clinical history, the assessment of important comorbidities and the key investigations needed to support them.

Exhaled nitric oxide monitoring does not reduce exacerbation frequency or inhaled corticosteroid dose in paediatric asthma: a randomised controlled trial

INTRODUCTION

Inhaled corticosteroid therapy (ICS) for asthma is currently modified according to symptoms and lung function. Fractional exhaled nitric oxide (FENO) has been demonstrated to be a non-invasive marker of eosinophilic inflammation. Studies of FENO-driven asthma management show variable success. Objectives: This study aimed to evaluate whether monitoring FENO can improve outpatient management of children with moderate to severe asthma using a pragmatic design.

METHODS

Children aged 6–17 years with moderate to severe asthma were recruited. Their asthma was stabilised before randomisation to FENO-driven therapy or to a standard management group where therapy was driven by conventional markers of asthma control. ICS or long-acting bronchodilator therapies were altered according to FENO levels in combination with reported symptoms in the FENO group. Participants were assessed 2 monthly for 12 months. ICS dose and exacerbation frequency change were compared between groups in an intention to treat analysis.

RESULTS

Ninety children were randomised. No difference was found between the two groups in either change in corticosteroid dose or exacerbation frequency. Results were similar in a planned secondary analysis of atopic asthmatics.

CONCLUSION

FENO-guided ICS titration does not appear to reduce corticosteroid usage or exacerbation frequency in paediatric outpatients with moderate to severe asthma. This may reflect limitations in FENO-driven management algorithms, as there are now concerns that FENO levels relate to atopy as much as they relate to asthma control.

Bronchial hyperresponsiveness to mannitol, airway inflammation and Asthma Control Test in atopic asthmatic children

INTRODUCTION

The aim of this study was to evaluate the relationship between airway hyperresponsiveness (AHR) to mannitol and bronchial inflammation measured as exhaled nitric oxide (FeNO) and to assess whether asthma control correlates with AHR to mannitol and FeNO in atopic asthmatic children.

MATERIAL AND METHODS

Allergy evaluation, the mannitol challenge test, FeNO levels and the Asthma Control Test (ACT) questionnaire were assessed in 40 children with intermittent and mild persistent allergic asthma.

RESULTS

All the subjects showed positive AHR to mannitol. Pearson's correlation test revealed a significant inverse correlation between AHR (mannitol PD15) and FeNO (p = 0.020). There was also a significant positive correlation between ACT and PD15 (p = 0.020) and a significant negative correlation between ACT and FeNO levels (p = 0.003). The study population was divided into two groups according to FeNO levels (group A ≥ 16 ppb vs. group B < 16 ppb). In group A mannitol PD15 was significantly lower (p = 0.040) and ACT score values were significantly lower (p = 0.001) compared to group B. In group A, the ACT showed that 13.3% of subjects had well-controlled asthma, 80% had partially controlled asthma and 6.7% had uncontrolled asthma. In group B, the ACT showed that 72% of subjects had well-controlled asthma and 28% had partially controlled asthma.

CONCLUSIONS

Our findings indicate that the degree of AHR to mannitol correlates with the degree of airway inflammation in asthmatic atopic children; moreover, better control of asthma correlates with a lower degree of AHR to both mannitol and FeNO.

Biomarkers and severe asthma: a critical appraisal

Severe asthma (SA) is a clinically and etiologically heterogeneous respiratory disease which affects among 5–10 % of asthmatic patients. Despite high-dose therapy, a large patients percentage is not fully controlled and has a poor quality of life. In this review, we describe the biomarkers actually known in scientific literature and used in clinical practice for SA assessment and management: neutrophils, eosinophils, periostin, fractional exhaled nitric oxide, exhaled breath condensate and galectins. Moreover, we give an overview on clinical and biological features characterizing severe asthma, paying special attention to the potential use of these ones as reliable markers. We finally underline the need to define different biomarkers panels to select patients affected by severe asthma for specific and personalized therapeutic approach.

Exhaled NO: Determinants and Clinical Application in Children With Allergic Airway Disease

Nitric oxide (NO) is endogenously released in the airways, and the fractional concentration of NO in exhaled breath (FeNO) is now recognized as a surrogate marker of eosinophilic airway inflammation that can be measured using a noninvasive technique suitable for young children. Although FeNO levels are affected by several factors, the most important clinical determinants of increased FeNO levels are atopy, asthma, and allergic rhinitis. In addition, air pollution is an environmental determinant of FeNO that may contribute to the high prevalence of allergic disease. In this review, we discuss the mechanism for airway NO production, methods for measuring FeNO, and determinants of FeNO in children, including host and environmental factors such as air pollution. We also discuss the clinical utility of FeNO in children with asthma and allergic rhinitis and further useful directions using FeNO measurement.

Does aspirin-induced oxidative stress cause asthma exacerbation?

Aspirin-induced asthma (AIA) is a distinct clinical syndrome characterized by severe asthma exacerbations after ingestion of aspirin or other non-steroidal anti-inflammatory drugs. The exact pathomechanism of AIA remains unknown, though ongoing research has shed some light. Recently, more and more attention has been focused on the role of aspirin in the induction of oxidative stress, especially in cancer cell systems. However, it has not excluded the similar action of aspirin in other inflammatory disorders such as asthma. Moreover, increased levels of 8-isoprostanes, reliable biomarkers of oxidative stress in expired breath condensate in steroid-naïve patients with AIA compared to AIA patients treated with steroids and healthy volunteers, has been observed. This review is an attempt to cover aspirin-induced oxidative stress action in AIA and to suggest a possible related pathomechanism.

Fractional exhaled nitric oxide (FeNo) in different asthma phenotypes

Fractioned exhaled nitric oxide (FeNO) is a noninvasive marker of inflammation in asthmatic patients. FeNO can be used to monitor airway inflammation, but individual responses make tailored interventions based on FeNO difficult. The correlation between the asthma control test (ACT), FEV1, and FeNO was evaluated in this study to ascertain the correct usage of FeNO with different asthma phenotypes regarding their control, allergy, comorbidity, obesity, age, smoking status, and severity. ACT, pulmonary function, and FeNO in 416 asthmatic patients on combined therapy were retrospective evaluated. Correlations between these parameters and the FeNO levels in different asthma phenotypes were calculated. In the study population, FeNO was 31.8 ± 28.5 parts per billion (ppb), FEV1 was 83.4 ± 19% and ACT was 19 ± 5.2. ACT scores were negatively correlated with FeNO (r = -0.31; p = 0.002). FeNO was different in patients with positive and negative skin-prick test (p < 0.05), with and without allergic rhinitis (p < 0.01), and with and without allergic conjunctivitis (p < 0.01). Significantly higher FeNO levels were found with logistic regression analysis only in patients with a history of emergency room visits (ERVs) (p = 0.024). The rate of the ERV of the patients with an ACT score more than or equal to 20 and with a FeNO value of more than 35 ppb was 22.9%, but with a FeNO value of less than 35 ppb was 6.5% (p = 0.004). Allergy and allergic comorbidities may lead to an increase in FeNO levels. Patients with a history of ERV have markedly higher FeNO levels, although they have an ACT score more than or equal to 20.

Pathophysiological characteristics of asthma in the elderly: a comprehensive study

BACKGROUND

Comprehensive studies of the pathophysiologic characteristics of elderly asthma, including predominant site of disease, airway inflammation profiles, and airway hyperresponsiveness, are scarce despite their clinical importance.

OBJECTIVE

To clarify the pathophysiologic characteristics of elderly patients with asthma.

METHODS

Patients older than 65 years (elderly; n = 45) vs those no older than 65 years (nonelderly; n = 67) were retrospectively analyzed by spirometry, computed tomographic indices of large airway wall thickness and small airway involvement (air trapping), impulse oscillation measurements, exhaled nitric oxide levels, blood and induced sputum cell differentials, methacholine airway responsiveness, and total and specific serum IgE levels.

RESULTS

Elderly patients with asthma had significantly lower values for forced expiration volume in 1 second, mid-forced expiratory flow (percentage predicted), and ratio of forced expiration volume in 1 second to forced vital capacity than nonelderly patients with asthma (median 81.2% vs 88.8%, P = .02; 50.9% vs 78.6%, P = .03; 0.72 vs 0.78, P = .001, respectively). In computed tomographic measurements, elderly patients with asthma had significantly greater airway wall thickening and air trapping than nonelderly patients. Impulse oscillation measurements indicated that elderly patients with asthma showed significantly greater resistance at 5 Hz (used as an index of total airway resistance), greater decrease in resistance from 5 to 20 Hz, a higher ratio of decrease in resistance from 5 to 20 Hz to resistance at 5 Hz, higher integrated area between 5 Hz and frequency of resonance, greater frequency of resonance, and lower reactance at a frequency of 5 Hz (potential markers of small airway disease) than nonelderly patients. There were no significant differences in blood or sputum cell differentials, exhaled nitric oxide, or methacholine airway responsiveness between the 2 groups. Total serum IgE levels and positive rates of specific IgE antibodies against several allergens were significantly lower in elderly than in nonelderly patients with asthma.

CONCLUSION

Based on spirometric, computed tomographic, and impulse oscillation analyses, elderly patients with asthma have greater involvement of small and large airways than nonelderly patients with asthma.

Longitudinal assessment of high versus low levels of fractional exhaled nitric oxide among children with asthma and atopy

PURPOSE

Fractional exhaled nitric oxide (FeNO) has emerged as an important biomarker in asthma. Increasing evidence points to atopy as a confounding factor in the interpretation of elevated FeNO. We conducted a longitudinal study to understand the clinical significance of FeNO as an inflammatory biomarker.

METHODS

We identified 19 children aged 13-15 years at baseline with a significant elevation in FeNO ≥ 80 parts per billion (ppb) and randomly selected a group of children of similar age with a moderate elevation (40-79 ppb) and normal-to-low FeNO (<40 ppb). Between November 2010 and July 2011, three additional study visits were conducted.

RESULTS

Ninety-three children participated in the study. There were 16, 24, and 53 participants in the high, mid, and low FeNO groups. During 1.5 years of follow-up, mean FeNO levels were 82.6 ppb (standard deviation [SD] = 65.9) for atopic asthmatics, 50.6 ppb (SD = 42.6) for nonasthmatic atopics, 17.0 ppb (SD = 10.8) for nonatopic asthmatics, and 17.8 ppb (SD = 13.9) for nonatopic nonasthmatics (p < 0.001). FeNO levels remained stable: 63 % of the high FeNO group had a FeNO ≥ 80 across all 4 measurements and 87 % of the normal-to-low FeNO group had a FeNO of <40 across all 4 measurements. The high FeNO group also was found to have an elevation in IL-5 (p = 0.04), IL-6 (p = 0.003), IL-10 (p = 0.002), and total serum IgE (p < 0.001), after adjustment by age, sex, height, body mass index, and atopy and asthma status.

CONCLUSIONS

An elevation of FeNO appears to indicate an atopic phenotype regardless of an asthma diagnosis, clinical symptoms, or corticosteroid use. An elevation of FeNO also is associated with a systemic elevation in inflammatory cytokines.

Clinical utility of asthma biomarkers: from bench to bedside

Asthma is a chronic disease characterized by airway inflammation, bronchial hyperresponsiveness, and recurrent episodes of reversible airway obstruction. The disease is very heterogeneous in onset, course, and response to treatment, and seems to encompass a broad collection of heterogeneous disease subtypes with different underlying pathophysiological mechanisms. There is a strong need for easily interpreted clinical biomarkers to assess the nature and severity of the disease. Currently available biomarkers for clinical practice - for example markers in bronchial lavage, bronchial biopsies, sputum, or fraction of exhaled nitric oxide (FeNO) - are limited due to invasiveness or lack of specificity. The assessment of markers in peripheral blood might be a good alternative to study airway inflammation more specifically, compared to FeNO, and in a less invasive manner, compared to bronchoalveolar lavage, biopsies, or sputum induction. In addition, promising novel biomarkers are discovered in the field of breath metabolomics (eg, volatile organic compounds) and (pharmaco)genomics. Biomarker research in asthma is increasingly shifting from the assessment of the value of single biomarkers to multidimensional approaches in which the clinical value of a combination of various markers is studied. This could eventually lead to the development of a clinically applicable algorithm composed of various markers and clinical features to phenotype asthma and improve diagnosis and asthma management.

Respiratory system reactance is an independent determinant of asthma control

The mechanisms underlying not well-controlled (NWC) asthma remain poorly understood, but accumulating evidence points to peripheral airway dysfunction as a key contributor. The present study tests whether our recently described respiratory system reactance (Xrs) assessment of peripheral airway dysfunction reveals insight into poor asthma control. The aim of this study was to investigate the contribution of Xrs to asthma control. In 22 subjects with asthma, we measured Xrs (forced oscillation technique), spirometry, lung volumes, and ventilation heterogeneity (inert-gas washout), before and after bronchodilator administration. The relationship between Xrs and lung volume during a deflation maneuver yielded two parameters: the volume at which Xrs abruptly decreased (closing volume) and Xrs at this volume (Xrscrit). Lowered (more negative) Xrscrit reflects reduced apparent lung compliance at high lung volumes due, for example, to heterogeneous airway narrowing and unresolved airway closure or near closure above the critical lung volume. Asthma control was assessed via the 6-point Asthma Control Questionnaire (ACQ6). NWC asthma was defined as ACQ6 > 1.0. In 10 NWC and 12 well-controlled subjects, ACQ6 was strongly associated with postbronchodilator (post-BD) Xrscrit (R(2) = 0.43, P < 0.001), independent of all measured variables, and was a strong predictor of NWC asthma (receiver operator characteristic area = 0.94, P < 0.001). By contrast, Xrs measures at lower lung volumes were not associated with ACQ6. Xrscrit itself was significantly associated with measures of gas trapping and ventilation heterogeneity, thus confirming the link between Xrs and airway closure and heterogeneity. Residual airway dysfunction at high lung volumes assessed via Xrscrit is an independent contributor to asthma control.

Fractional exhaled nitric oxide in healthy non-asthmatic 7-year olds and prenatal exposure to polycyclic aromatic hydrocarbons: nested regression analysis

The main goal of the study was to assess possible association between transplacental exposure to genotoxic PAH compounds assessed by the cord blood PAH-DNA adducts and fractional exhaled nitric oxide (FeNO) measured in healthy non-asthmatic children at the age of 7 years. The subjects included the subsample of 89 children who took part in the ongoing population based birth cohort study in Krakow and attended FeNO testing. The effect of transplacental PAH exposure was adjusted for potential confounders, such as maternal allergy and children's specific atopy to common domestic allergens.

RESULTS

FeNO values were significantly elevated in children with higher prenatal PAH exposure (gmean = 7.7 ppb; 95% CI: 5.8-10.2 ppb) compared with those at low exposure level (gmean = 3.8 ppb; 95% CI: 2.3-6.3) (P = 0.011). Children with maternal allergy had also significantly higher mean FeNO values (gmean = 13.7 ppb, 95% CI: 8.8-21.4 ppb) compared with the subjects whose mothers denied allergy (gmean = 5.6 ppb, 95% CI: 4.3-7.3 ppb) (P = 0.012). Similarly, FeNO values in atopic children were higher (gmean = 11.2 ppb; 95% CI: 3.8-32.8 ppb) than in non-atopic individuals (gmean = 6.0 ppb; 95% CI: 4.7-7.7 ppb, P = 0.079). The results of the nested multivariable linear regression analysis showed that both maternal allergy and sensitization of children to domestic aeroallergens jointly explained 10.4% of FeNO variance, however, the additional 10.9% was determined by prenatal PAH exposure.

CONCLUSION

FeNO is more than a marker useful for screening atopy or symptomatic bronchial inflammation and may also be a proxy for cytokine deregulation and "allergic response" phenotype possibly established in fetal period due to transplacental PAH exposure. Preliminary results of our study should encourage more studies on intrauterine PAH exposure and later respiratory symptoms.

Four of a kind: asthma control, FEV1, FeNO, and psychosocial problems in adolescents

BACKGROUND

Many adolescents have poor asthma control and are at high risk for psychosocial problems. However, structured assessment of asthma control or psychosocial problems is still not implemented in routine asthma care. Pediatricians typically rely on their clinical view and physiological measurements. To date, it is unknown whether clinical and patient reported outcomes are interrelated. Furthermore, there is no consensus on who should be the informant; the adolescent or his caregiver. STUDY AIM(S): This study aimed to assess the relationship between patient and caregiver reported outcomes [Asthma Control Questionnaire and Strengths and Difficulties Questionnaire (SDQ)] and physiological parameters (FEV1 and Fractional exhaled Nitric Oxide) in adolescents (aged 11-16) with asthma.

METHODS

A multicenter observational study was performed in four Dutch pediatric outpatient departments. Association between asthma control, physiological parameters, and results of psychosocial questionnaires completed by both adolescent and caregiver was analyzed.

RESULTS

Forty-eight adolescents and their caregivers participated in this study. Asthma was uncontrolled in about 30%. Asthma control was not associated with age, gender, FEV1, FeNO, or psychosocial problems. Agreement between adolescents and caregivers about how well asthma was controlled was moderate (κ = 0.577, P < 0.01).

DISCUSSION

Asthma control, physiological parameters, and psychosocial problems are different domains of health status. It could be suggested to use validated patient and caregiver reported outcomes in routine adolescent asthma care.

CONCLUSION

Patient and caregiver reported outcomes on asthma control and the presence of psychosocial problems add valuable, unique information to physiological parameters in adolescent asthma management.

Comparison of orally exhaled nitric oxide in allergic versus nonallergic rhinitis

BACKGROUND

Fractional exhaled nitric oxide (FeNO), a well-known marker of airway inflammation, is rarely evaluated in rhinitis of different etiology. We aimed to compare the eNO levels in allergic rhinitis (AR) and nonallergic rhinitis (NAR) with/without asthma, as well as the contributing factors that interfere with elevated FeNO.

METHODS

Patients were enrolled based on chronic nasal symptoms. Orally exhaled NO was measured with the single exhalation method at 50 mL/s. All subjects underwent a panel of tests: skin-prick tests, asthma control test, blood sampling, spirometry, and health-related quality-of-life questionnaires.

RESULTS

The study group consisted of mainly women (130 women/41 men), with a mean age of 32.6 ± 13.2 years. AR was diagnosed in 122 (78.2%), NAR in 34 (21.8%), and 15 subjects were healthy controls. FeNO was insignificantly higher in patients with AR compared with patients with NAR and controls (32.2 parts per billion [ppb] versus 27 and 19.4 ppb), with no difference between genders. NAR + asthma had higher FeNO than those without asthma (40.5 ppb versus 14.9 ppb; p < 0.03), whereas accompanying asthma did not affect FeNO levels in the AR group. AR ± asthma had significantly higher FeNO levels than the NAR-only group (p < 0.01). Among AR + asthma, perennial sensitization caused higher FeNO levels than did seasonal allergens (48.5 ± 33.9 and 19.5 ± 13.6' p = 0.003), whereas FeNO was significantly higher during the allergen season. Nasally inhaled corticosteroids insignificantly reduced FeNO levels in all groups. Severity and seasonality of rhinitis, asthma, and ocular symptoms, but not gender, age, body mass index, Total IgE, forced expiratory volume in 1 second, and smoking, were associated with FeNO.

CONCLUSION

Rhinitis and comorbid asthma are responsible for increased FeNO, irrespective of atopy. However, NAR without asthma may not be considered as a strong risk factor for airway inflammation.

Clinical applications of lung function tests: a revisit

The development and clinical application of lung function tests have a long history, and the various components of lung function tests provide very important tools for the clinical evaluation of respiratory health and disease. Spirometry, measurement of the diffusion factor, bronchial provocation tests and forced oscillation techniques have found diverse clinical applications in the diagnosis and monitoring of respiratory diseases, such as chronic obstructive pulmonary disease, interstitial lung diseases and asthma. However, there are some practical issues to be resolved, including the establishment of reference values for individual test parameters and the roles of these tests in preoperative risk assessment and pulmonary rehabilitation. Novel measurements, including negative expiratory pressure, the fraction of exhaled nitric oxide and analysis of exhaled breath condensate, may provide new insights into physiological abnormalities or airway inflammation in respiratory diseases, but their clinical applications need to be further evaluated. The clinical application of lung function tests continues to face challenges, which may be overcome by further improvement of conventional techniques for lung function testing and further specification of new testing techniques.

Lung function and biomarkers of airway inflammation during and after hospitalization for acute exacerbations of childhood asthma associated with viral respiratory symptoms

BACKGROUND

There are limited data assessing relationships between biomarkers of inflammation and lung function after hospitalization for asthma exacerbations in children.

OBJECTIVE

To assess the associations in asthmatic children among changes in lung function, fraction of exhaled nitric oxide (FENO), and cysteinyl leukotrienes (CysLTs) in exhaled breath condensate (EBC) after hospitalization for acute asthma.

METHODS

Spirometry and FENO were measured and EBC collected for CysLT measurement from 40 children during and 1, 2, and 4 weeks after hospitalization for an asthma exacerbation and during a single-study visit for 40 healthy children.

RESULTS

Enrollment FENO and EBC CysLT concentrations were higher in the children with asthma than in healthy individuals (mean FENO, 31.6 vs 7 ppb; P < .0001; mean EBC CysLT, 7.9 vs 4.9 ppb; P = .03). Among children with asthma, improvement in lung function reached a plateau within 2 weeks after hospital discharge. The EBC CysLT concentrations were not associated with changes in lung function, use of albuterol, or use of inhaled corticosteroids (ICSs). Among asthmatic children enrollment FENO was not associated with changes in lung function during follow-up. However, among children who had an elevated enrollment FENO (≥25 ppb), patients who did not use ICSs after hospital discharge had lower end-of-study lung function than those who used ICSs. At 2 and 4 weeks after hospital discharge, FENO was higher among patients who reported albuterol use more than twice weekly and among patients who reported no ICS use.

CONCLUSION

FENO measured at hospital discharge among children hospitalized with acute asthma may be useful in identifying patients who will respond to ICS therapy.

Does asthma control as assessed by the asthma control test reflect airway inflammation?

BACKGROUND AND AIMS

The treatment of asthmatic patients is particularly focused on the control of symptoms as well as functional and inflammatory parameters. In our study, we investigated the relationship between the asthma control test (ACT) which evaluates symptoms and airway inflammation and functional parameters.

MATERIALS AND METHODS

Stable asthmatic patients admitted to our pulmonary outpatient clinic were enrolled in the study consecutively and underwent the ACT, pulmonary function tests and methacholine bronchial provocation test (MBPT). Additionally, fractional exhaled nitric oxide level (FeNO) and induced sputum cell distribution were assessed. All these parameters were re-evaluated at the third month after adjusting medications of the patients according to baseline ACT scores.

RESULTS

Of the 101 patients screened, we analyzed 83 who proceeded to the follow up visit. At the baseline visit, 8 were totally controlled, 36 partially controlled and 39 uncontrolled according to ACT. At the follow up visit, 10 were totally controlled, 39 partially controlled and 34 uncontrolled. Comparison of the two visits in terms of all parameters revealed significant reductions only in the percentages of patients with MBPT positivity (p = 0.029) and FeNO levels > 20 ppb (p = 0.025) at follow up. The percentages of patients with FeNO > 20 ppb, MBPT positivity, induced sputum eosinophilia or induced sputum neutrophilia did not show significant differences between totally controlled, partially controlled and uncontrolled groups at both baseline and follow up visits.

CONCLUSION

Although the ACT scores did not show significant correlations with the airway inflammation parameters tested in this study, a marked reduction in the percentage of patients with MBPT positivity and FeNO > 20 ppb at follow up may suggest the importance of the control concept in the management of asthma.

The role of measuring airway hyperresponsiveness and inflammatory biomarkers in asthma

Asthma is characterized by inflammation and airway hyperresponsiveness, which results in episodic airflow obstruction. It is diagnosed once a compatible clinical history plus objective evidence of diurnal variability in peak expiratory flow or significant reversibility to inhaled bronchodilator is documented. In accordance with current guidelines, measures of airway calibre and symptoms allow patients and clinicians to assess the degree of asthma control and titrate pharmacotherapy. However, these parameters fail to reflect the extent of underlying endobronchial inflammation and airway hyperresponsiveness, which in turn suggests that additional measures of asthma control may be of benefit. This evidence-based review highlights ways by which inflammation and airway hyperresponsiveness can be assessed and how they may provide additional useful information in the diagnosis and management of asthmatic patients.

Subjects in a Population Study with High Levels of FENO Have Associated Eosinophil Airway Inflammation

Background. Measurement of fraction of exhaled nitric oxide (FENO) is a promising tool to increase validity in epidemiological studies of asthma. The association between airway inflammation and FENO has, however, only been examined in clinical settings and may be biased by selection of patients with asthma. Methods. In a population study with FENO registrations on 370 individuals, we identified nine subjects out of thirty subjects with high levels of FENO (>85th percentile, 30.3 ppb), irrespective of presence of respiratory symptoms, and 21 control subjects with FENO at median levels (11.1–16.4 ppb) willing to undergo bronchoscopy and bronchoalveolar lavage (BAL), all nonsmokers. FENO was measured in accordance with ATS criteria, and the examination also included spirometry, methacholine challenge test, and sampling of exhaled breath condensate (EBC). Results. Subjects with high FENO levels had significantly higher median the percentage of eosinophils in BAL than controls (2.1 versus 0.6, P < .006), and there was a significant association between FENO and the percentage of eosinophils in BAL (ρ=0.6, P < .002) and ECP in BAL (ρ=0.65, P < .05) examining the whole group, but no association with gender, FEV1, or degree of metacholine sensitivity or any of the biomarkers in EBC. All subjects with high FENO had respiratory symptoms, but only three had diagnosed asthma. There were a significant association between hydrogen peroxide in EBC and the percentage of neutrophils in bronchial wash. Conclusion. High FENO levels signal asthmatic or allergic respiratory disease in a population-based study. FENO levels are associated with degree of eosinophil airway inflammation as measured by the percentage of eosinophils and ECP in BAL.

Actual control state of intermittent asthma classified on the basis of subjective symptoms

BACKGROUND

Many primary care physicians begin treatment of asthma patients on the basis of their subjective symptoms. We hypothesized that patients diagnosed as having intermittent asthma on the basis of subjective symptoms by a primary care physician may have their asthma severity underestimated.

METHODS

We investigated 293 patients who were in their 20s and diagnosed as having asthma. Two hundred and fifteen patients with intermittent asthma diagnosed on the basis of subjective symptoms were chosen. We evaluated their asthma severity using FEV(1) (% predicted), airway hyperresponsiveness to histamine dihydrochloride, and exhaled nitric oxide level as factors that determine asthma severity.

RESULTS

Among these patients, 27.8% were determined to have moderate or severe asthma by the pulmonary function test. History of childhood asthma was the only significant risk factor for a low pulmonary function. Among the patients, 60.9% showed moderate or severe airway hyperresponsiveness. History of childhood asthma was the only significant risk factor for the increase in airway hyperresponsiveness. Moreover, 53.8% showed a high exhaled nitric oxide level. History of childhood asthma was associated with an increased risk of a high eNO level as determined by univariate analysis, but no significant difference was observed in the comparison by multiple logistic regression analysis. The percentage of subjects classified into the mild group by all of the results of the three tests was only 20.6%.

CONCLUSION

We showed that asthma severity classified on the basis of only subjective symptoms may be underestimated in young adults. We showed that the diagnosis of mild intermittent asthma needs to be determined carefully.

Forced expiratory flow between 25% and 75% of vital capacity and FEV1/forced vital capacity ratio in relation to clinical and physiological parameters in asthmatic children with normal FEV1 values

BACKGROUND

The assumption that the assessment of forced expiratory flow between 25% and 75% of vital capacity (FEF(25-75)) does not provide additional information in asthmatic children with normal FEV(1) percent predicted has not been adequately tested.

OBJECTIVE

We sought to determine whether the measurement of FEF(25-75) percent predicted offers advantages over FEV(1) percent predicted and FEV(1)/forced vital capacity (FVC) percent predicted for the evaluation of childhood asthma.

METHODS

This is a secondary analysis of data from the Pediatric Asthma Controller Trial and the Characterizing the Response to a Leukotriene Receptor Antagonist and Inhaled Corticosteroid trials. Pearson correlation coefficients, Pearson partial correlation coefficients, canonical correlations, and receiver operating characteristic (ROC) curves were constructed.

RESULTS

Among 437 children with normal FEV(1) percent predicted, FEF(25-75) percent predicted, and FEV(1)/FVC percent predicted were (1) positively correlated with log(2) methacholine PC(20), (2) positively correlated with morning and evening peak expiratory flow percent predicted, and (3) negatively correlated with log(10) fraction of exhaled nitric oxide and bronchodilator responsiveness. Pearson partial correlations and canonical correlations indicated that FEF(25-75) percent predicted was better correlated with bronchodilator responsiveness and log(2) methacholine PC(20) than were FEV(1) percent predicted or FEV(1)/FVC percent predicted. In the ROC curve analysis, FEF(25-75) at 65% of predicted value had a 90% sensitivity and a 67% specificity for detecting a 20% increase in FEV(1) after albuterol inhalation.

CONCLUSION

FEF(25-75) percent predicted was well correlated with bronchodilator responsiveness in asthmatic children with normal FEV(1). FEF(25-75) percent predicted should be evaluated in clinical studies of asthma in children and might be of use in predicting the presence of clinically relevant reversible airflow obstruction.

Influence of atopy and asthma on exhaled nitric oxide in an unselected birth cohort study

BACKGROUND

Asthma is considered to be associated with elevated levels of exhaled nitric oxide (FeNO). The nature of this relationship and how it is influenced by atopy are still not resolved.

METHODS

The Isle of Wight birth cohort (N=1456) was reassessed at 18 years of age. Participants able to attend the research centre were assessed by questionnaires, skin prick testing and FeNO in order to explore the interrelationship between asthma, atopy and FeNO.

RESULTS

Atopy was significantly associated with higher levels of FeNO. However, the level of FeNO for non-atopic asthmatic participants was no different to the non-atopic no-asthma group. The highest levels of FeNO were seen in subjects with both atopy and asthma. In addition, FeNO was positively associated with increasing atopic burden as evidenced by increasing FeNO with increasing skin prick testing positivity, and with increasing severity of atopic asthma as evidenced by the number of attacks of wheezing. FeNO and current inhaled corticosteroid use were not significantly associated.

CONCLUSIONS

FeNO behaves as a biomarker of atopy and the "allergic asthma" phenotype rather than asthma itself. This may explain why FeNO-guided asthma treatment outcomes have proved to be of limited success where atopic status has not been considered and accounted for.

Multicentre trial evaluating alveolar NO fraction as a marker of asthma control and severity

BACKGROUND

Exhaled NO can be partitioned in its bronchial and alveolar sources, and the latter may increase in the presence of recent asthmatic symptoms and in refractory asthma. The aim of this multicentre prospective study was to assess whether alveolar NO fraction and FE(NO) could be associated with the level of asthma control and severity both at the time of measurement and in the subsequent 3 months.

METHODS

Asthma patients older than 10 years, nonsmokers, without recent exacerbation and under regular treatment, underwent exhaled NO measurement at multiple constant flows allowing its partition in alveolar (with correction for back-diffusion) and bronchial origins based on a two-compartment model of NO exchange; exhaled NO fraction at 50 ml/s (FE(NO,0.05)) was also recorded. On inclusion, severity was assessed using the four Global initiative for asthma (GINA) classes and control using Asthma Control Questionnaire (ACQ). Participants were followed-up for 12 weeks, control being assessed by short-ACQ on 1st, 4th, 8th and 12th week.

RESULTS

Two-hundred patients [107 children and 93 adults, median age (25th; 75th percentile) 16 years (12; 38)], 165 receiving inhaled corticosteroid, were included in five centres. The two-compartment model was valid in 175/200 patients (87.5%). Alveolar NO and FE(NO,0.05) did not correlate to control on inclusion or follow-up (either with ACQ /short-ACQ values or their changes), nor was influenced by severity classes. Alveolar NO negatively correlated to MEF(25-75%) (rho = -0.22, P < 0.01).

CONCLUSION

Alveolar and exhaled NO fractions are not indexes of control or severity in asthmatic children and adults under treatment.

Utility of exhaled nitric oxide in the diagnosis and management of asthma

PURPOSE OF REVIEW

The fraction of nitric oxide in exhaled air (FeNO) is elevated in the presence of airway inflammation, and it may be a useful biomarker in asthma. The purpose of the present review is to highlight the current literature investigating the use of exhaled nitric oxide in the diagnosis and management of asthma.

RECENT FINDINGS

The measurement of exhaled nitric oxide has been studied in normal populations and in asthmatics. FeNO appears to be a useful screening tool for asthma, although nondisease factors may confound the interpretation of an elevated FeNO level. Clinical trials investigating the use of FeNO measurements in predicting asthma exacerbation and tailoring maintenance therapy have had varying success. Further studies incorporating individualized FeNO profiles into treatment algorithms are needed.

SUMMARY

FeNO shows promise as a tool in the diagnosis and treatment of asthma. However, further studies are needed to address outstanding questions about its exact role in guiding asthma management.

Changes in exhaled nitric oxide measured by two offline methods predict improvements in bronchial hyperresponsiveness after inhaled steroid therapy in Japanese adults with asthma

BACKGROUND

The fraction of exhaled nitric oxide (FeNO) is a useful marker of eosinophilic airway inflammation in asthmatics. No studies have examined the relationship between the change in FeNO levels measured offline and changes in bronchial hyperresponsiveness (BHR) in asthmatic patients treated with inhaled corticosteroids (ICS). The objective of this study was to investigate the relationship between the change in FeNO levels measured offline and the change in BHR to acetylcholine in asthmatic patients taking ICS.

METHODS

The study population comprised 41 ICS-treated asthmatics from our outpatient clinic. We measured FeNO levels by two methods -with a Sievers kit ("FeNOs") and with a kit from the Center for Environmental Information Science, Japan ("FeNOc") at baseline and after 1 year of regular treatment. We also used spirometry to test BHR to acetylcholine (PC(20Ach)).

RESULTS

The mean of duration of observation was 406 days. There were significant relationships between DeltalogPC(20Ach) and logPC(20Ach) (r = -0.877, P < 0.001), FeNOs (r = 0.465, P = 0.002), and FeNOc (r = 0.524, P = 0.004) at baseline, but not with age, the dose of ICS, FEV(1), or %FEV(1). Moreover, there was a significant relationship between DeltalogPC(20Ach) and DeltaFeNOs (r = -0.386, P = 0.013) and DeltaFeNOc (r = -0.473, P = 0.004), but not with DeltaFEV(1).

CONCLUSIONS

Changes in FeNOs and FeNOc correlated with improvements in BHR to acetylcholine in adult asthmatics after ICS therapy. Our findings suggest that offline monitoring of FeNO will facilitate the management of bronchial asthma in patients treated with ICS.

The diagnosis of asthma and exercise-induced bronchospasm in division I athletes

OBJECTIVE

To determine the accuracy of clinically diagnosed exercise-induced bronchospasm (EIB) and asthma among National Collegiate Athletic Association Division I student athletes.

DESIGN

Cohort study.

SETTING

Division I university athletic department and primary care sports medicine clinic/athletic training room.

PATIENTS

All varsity athletes were eligible for the study. Seventy-five participants entered the study; 74 completed all the study protocols.

INTERVENTIONS

Study participants underwent measurement of exhaled nitric oxide (eNO), followed by baseline spirometry. Eucapnic voluntary hyperventilation (EVH) was then performed, followed by spirometry every 3 minutes for a total of 21 minutes to measure change in forced expiratory volume in 1 second.

MAIN OUTCOME MEASURES

Exhaled nitric oxide levels, baseline spirometry, and response of forced expiratory volume in 1 second to EVH.

RESULTS

There were a total of 16 subjects with a positive EVH test. There were 16 (80%) individuals using a bronchodilator who had a negative EVH test versus 4 (20%) who had a positive test. Mean eNO values were different across subject groups defined by treatment status, although not statistically significant. The highest mean eNO value of 24.32 ppb was found in subjects only taking bronchodilators compared with the lowest mean value of 16.75 ppb in athletes who were not taking any medications.

CONCLUSIONS

The results from this study provide further evidence to support the need for objective testing to correctly diagnose EIB. These data suggest that measuring eNO may help to distinguish truly isolated EIB from asthma in athletes, but a larger study is needed to confirm these initial observations.