Anti-inflammatory treatment of atopic asthma guided by exhaled nitric oxide: a randomized, controlled trial

Higher Prevalence and Severity of Eosinophilic Otitis Media in Patients with Asthma-COPD Overlap Compared with Asthma Alone

INTRODUCTION

Eosinophilic otitis media (EOM) is well-known to frequently co-exist with adult-onset asthma. Both diseases are similar type 2 inflammation and are considered to have a "one airway, one disease" relationship. Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO), characterized by airway obstruction caused by airway wall thickening (AWT), is a severe condition with a higher incidence of mortality compared to asthma alone or COPD alone. Based on the "one airway, one disease" concept, we hypothesized that the inflammatory pathophysiology of EOM differs depending on its comorbidity with ACO or with asthma alone.

METHODS

A total of 77 chronic rhinosinusitis (CRS) patients with asthma were enrolled in this study. The subjects were divided into 2 groups: a group with comorbid asthma alone (asthma group; 46 patients), and a group with comorbid ACO (ACO group; 31 patients). The 2 groups were compared and assessed with regard to various factors, including the patients' clinical characteristics, prevalence rate of EOM, EOM severity, EOMs relationships with smoking and AWT, and the eosinophil and neutrophil cell counts in the middle ear effusion (MEE).

RESULTS

The ACO group included significantly more males (p < 0.05), was significantly older (p < 0.05), and showed significantly lower lung function values (FEV1 [L], FEV1 [%pred]) (p < 0.01) compared with the asthma group. The ACO group also had a significant history of smoking as shown by the Brinkman index (p < 0.01) and greater AWT as assessed by high-resolution computed tomography (p < 0.05). The EOM prevalence rate was significantly higher in the ACO group (p < 0.05), especially with increased ACO severity (p < 0.05). The EOM severity was also significantly higher in the ACO group (p < 0.05) and also correlated with the ACO severity (p < 0.05). The pretreatment ear clinical characteristics score and the average air conduction hearing level were significantly higher in the ACO group (p < 0.05). The eosinophil percentage in the MEE/otorrhea was significantly lower in the ACO group (25.3%) than in the asthma group (54.7%) (p < 0.05). Conversely, the neutrophil percentage was significantly higher in the ACO group (75.7% vs. 41.9%) (p < 0.05).

CONCLUSIONS

Our findings suggest that, in CRS patients with asthma, comorbidity with ACO may be a clinical factor leading to increased EOM prevalence and severity, as well as a higher neutrophil infiltration percentage in the middle ear. Cessation of smoking and early therapeutic intervention for ACO may mitigate progression of bronchial remodeling (i.e., reduce AWT) and help reduce the prevalence and severity of EOM.

Effectiveness of FeNO-guided treatment in adult asthma patients: A systematic review and meta-analysis

OBJECTIVE

Asthma control is generally monitored by assessing symptoms and lung function. However, optimal treatment is also dependent on the type and extent of airway inflammation. Fraction of exhaled Nitric Oxide (FeNO) is a noninvasive biomarker of type 2 airway inflammation, but its effectiveness in guiding asthma treatment remains disputed. We performed a systematic review and meta-analysis to obtain summary estimates of the effectiveness of FeNO-guided asthma treatment.

DESIGN

We updated a Cochrane systematic review from 2016. Cochrane Risk of Bias tool was used to assess risk of bias. Inverse-variance random-effects meta-analysis was performed. Certainty of evidence was assessed using GRADE. Subgroup analyses were performed based on asthma severity, asthma control, allergy/atopy, pregnancy and obesity.

DATA SOURCES

The Cochrane Airways Group Trials Register was searched on 9 May 2023.

ELIGIBILITY CRITERIA

We included randomized controlled trials (RCTs) comparing the effectiveness of a FeNO-guided treatment versus usual (symptom-guided) treatment in adult asthma patients.

RESULTS

We included 12 RCTs (2,116 patients), all showing high or unclear risk of bias in at least one domain. Five RCTs reported support from a FeNO manufacturer. FeNO-guided treatment probably reduces the number of patients having ≥1 exacerbation (OR = 0.61; 95%CI 0.44 to 0.83; six RCTs; GRADE moderate certainty) and exacerbation rate (RR = 0.67; 95%CI 0.54 to 0.82; six RCTs; moderate certainty), and may slightly improve Asthma Control Questionnaire score (MD = -0.10; 95%CI -0.18 to -0.02, six RCTs; low certainty), however, this change is unlikely to be clinically important. An effect on severe exacerbations, quality of life, FEV1, treatment dosage and FeNO values could not be demonstrated. There were no indications that effectiveness is different in subgroups of patients, although evidence for subgroup analysis was limited.

CONCLUSIONS

FeNO-guided asthma treatment probably results in fewer exacerbations but may not have clinically important effects on other asthma outcomes.

1-Year Prospective Study of the Relationship of Serial Exhaled Nitric Oxide Level and Asthma Control

Background and Objective

Previous studies found that the fractional nitric oxide concentration in exhaled breath (FeNO) levels in healthy Chinese adults was higher than in White adults. More understanding of serial changes of FeNO levels with asthma control in a real-life clinical setting would be important to explore the utility of this biomarker in routine asthma management. This study assessed the FeNO levels of Chinese asthma subjects with different levels of asthma control and the serial changes with respect to the changes in asthma control over 1 year.

Methods

A 12-month prospective study (subjects recruited between November 2019 and January 2021) with serial measurement of FeNO levels at baseline, 4, 8 and 12 months. Asthma control was assessed by the Global Initiative for Asthma classification, Asthma Control Test (ACT) and Asthma Control Questionnaire (ACQ).

Results

Altogether, 136 subjects (mean age 51.51±15.09 years, 46[33.8%] male) had successful baseline FeNO measurements. At baseline, the FeNO levels did not show a statistically significant difference for controlled, partly controlled and uncontrolled asthma according to GINA classification, ACT and ACQ. FeNO levels decreased with improving asthma control and stayed at similar levels with unchanged or worsening asthma control for all subjects. For subjects with baseline blood eosinophil levels ≥300 cells/µL(n=59), FeNO levels decreased with improving asthma control, stayed similar without change for asthma control and increased with worsening asthma control. Receiver operating characteristic (ROC) analysis with the highest area under curve (AUC) for changes in FeNO levels for improving asthma control was between ≤ -10 to -25 ppb at various time points in the 12-month study.

Conclusion

Changes in FeNO levels over time were associated with changes in clinical asthma control, particularly in those with higher blood eosinophil count and are likely more useful than a single time point measurement in managing asthma.

Economic Evaluation of the Use of FeNO for the Diagnosis and Management of Asthma Patients in Primary Care in Sweden

OBJECTIVE

To determine the economic impact of the fraction of exhaled nitric oxide (FeNO) in asthma diagnosis and management in primary care in Sweden.

METHODS

An economic model has been developed to determine the economic impact of the fraction of exhaled nitric oxide (FeNO) in asthma diagnosis and management in primary care in Sweden. The model includes the use and cost of commonly used tests, the associated outcomes and diagnostic accuracy. We compared FeNO with spirometry and reversibility testing, methacholine challenge test, allergy testing, and blood eosinophil count. One-way sensitivity analyses were performed to confirm the robustness of results.

RESULTS

Adding FeNO measurement in asthma diagnosis resulted in cost savings of SEK 672 per patient by the fourth year. The use of FeNO testing in asthma management proved to be a dominant strategy when compared with each other test except methacholine challenge test. Sensitivity analyses confirmed the robustness of the results.

CONCLUSION

Introducing FeNO testing in clinical practice for the diagnosis and management of asthma in primary care in Sweden is less costly than standard methods while providing similar health benefits.

Managing Asthma in Adolescents and Adults: 2020 Asthma Guideline Update From the National Asthma Education and Prevention Program

IMPORTANCE

Asthma is a major public health problem worldwide and is associated with excess morbidity, mortality, and economic costs associated with lost productivity. The National Asthma Education and Prevention Program has released the 2020 Asthma Guideline Update with updated evidence-based recommendations for treatment of patients with asthma.

OBJECTIVE

To report updated recommendations for 6 topics for clinical management of adolescents and adults with asthma: (1) intermittent inhaled corticosteroids (ICSs); (2) add-on long-acting muscarinic antagonists; (3) fractional exhaled nitric oxide; (4) indoor allergen mitigation; (5) immunotherapy; and (6) bronchial thermoplasty.

EVIDENCE REVIEW

The National Heart, Lung, and Blood Advisory Council chose 6 topics to update the 2007 asthma guidelines based on results from a 2014 needs assessment. The Agency for Healthcare Research and Quality conducted systematic reviews of these 6 topics based on literature searches up to March-April 2017. Reviews were updated through October 2018 and used by an expert panel (n = 19) that included asthma content experts, primary care clinicians, dissemination and implementation experts, and health policy experts to develop 19 new recommendations using the GRADE method. The 17 recommendations for individuals aged 12 years or older are reported in this Special Communication.

FINDINGS

From 20 572 identified references, 475 were included in the 6 systematic reviews to form the evidence basis for these recommendations. Compared with the 2007 guideline, there was no recommended change in step 1 (intermittent asthma) therapy (as-needed short-acting β2-agonists [SABAs] for rescue therapy). In step 2 (mild persistent asthma), either daily low-dose ICS plus as-needed SABA therapy or as-needed concomitant ICS and SABA therapy are recommended. Formoterol in combination with an ICS in a single inhaler (single maintenance and reliever therapy) is recommended as the preferred therapy for moderate persistent asthma in step 3 (low-dose ICS-formoterol therapy) and step 4 (medium-dose ICS-formoterol therapy) for both daily and as-needed therapy. A short-term increase in the ICS dose alone for worsening of asthma symptoms is not recommended. Add-on long-acting muscarinic antagonists are recommended in individuals whose asthma is not controlled by ICS-formoterol therapy for step 5 (moderate-severe persistent asthma). Fractional exhaled nitric oxide testing is recommended to assist in diagnosis and monitoring of symptoms, but not alone to diagnose or monitor asthma. Allergen mitigation is recommended only in individuals with exposure and relevant sensitivity or symptoms. When used, allergen mitigation should be allergen specific and include multiple allergen-specific mitigation strategies. Subcutaneous immunotherapy is recommended as an adjunct to standard pharmacotherapy for individuals with symptoms and sensitization to specific allergens. Sublingual immunotherapy is not recommended specifically for asthma. Bronchial thermoplasty is not recommended as part of standard care; if used, it should be part of an ongoing research effort.

CONCLUSIONS AND RELEVANCE

Asthma is a common disease with substantial human and economic costs globally. Although there is no cure or established means of prevention, effective treatment is available. Use of the recommendations in the 2020 Asthma Guideline Update should improve the health of individuals with asthma.

2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group

The 2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group was coordinated and supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. It is designed to improve patient care and support informed decision making about asthma management in the clinical setting. This update addresses six priority topic areas as determined by the state of the science at the time of a needs assessment, and input from multiple stakeholders:A rigorous process was undertaken to develop these evidence-based guidelines. The Agency for Healthcare Research and Quality's (AHRQ) Evidence-Based Practice Centers conducted systematic reviews on these topics, which were used by the Expert Panel Working Group as a basis for developing recommendations and guidance. The Expert Panel used GRADE (Grading of Recommendations, Assessment, Development and Evaluation), an internationally accepted framework, in consultation with an experienced methodology team for determining the certainty of evidence and the direction and strength of recommendations based on the evidence. Practical implementation guidance for each recommendation incorporates findings from NHLBI-led patient, caregiver, and clinician focus groups. To assist clincians in implementing these recommendations into patient care, the new recommendations have been integrated into the existing Expert Panel Report-3 (EPR-3) asthma management step diagram format.

Reference Ranges and Determinant Factors for Fractional Exhaled Nitric Oxide in a Healthy Saudi Adult Population

BACKGROUND Fractional exhaled nitric oxide (FENO) has emerged as a promising marker in respiratory research. The aim of this study was to determine the reference range values of FENO for healthy Saudi adults and the factors associated with FENO levels. MATERIAL AND METHODS This cross-sectional study was conducted at the Department of Physiology, King Saud University, Riyadh, Saudi Arabia, from January 2016 to August 2017. A total of 429 healthy Saudi adults were initially recruited. The final selection included 412 participants, consisting of 307 men and 105 women. FENO measurements were performed according to the current recommendations of the American Thoracic Society. RESULTS We observed that the FENO levels of women were significantly lower than those of men (18.6 vs. 21.3, P=0.009). In women, the measured FENO ranged from 5.7 ppb to 42 ppb, and in men from 5.0 ppb to 55.0 ppb. The mean FENO level in the entire study population was 20.6, with a range of 5.0 ppb to 55.0 ppb. The difference became non-significant when we calculated the FENO after adjusting for body surface area by different percentile distributions. Multiple linear regression analysis showed that body surface area and weight were significant predictors of FENO levels. CONCLUSIONS In this study, FENO levels were significantly affected by demographic variables. Therefore, it is important to consider the factors influencing FENO values to make a valid clinical interpretation.

Study of the beneficial role of exhaled nitric oxide in combination with GINA guidelines for titration of inhaled corticosteroids in children with asthma

BACKGROUND

The use of FE_NO in association with current guidelines in the treatment of asthma has not been studied thoroughly. This study aimed to evaluate the beneficial role of FE_NO in combination with GINA (Global Initiative for Asthma) guidelines for titration of inhaled corticosteroids (ICS) in asthmatic children.

METHODS

It was a prospective and descriptive study. Uncontrolled asthmatic children were randomized to two groups: group 1 (followed GINA guidelines) or group 2 (followed GINA guidelines + FE_NO modification for ICS titration). The two groups were followed-up for 12 months.

RESULTS

The mean age of the patients in the study was 10 ± 4 years for group 1 (n = 116) and 11 ± 5 years for group 2 (n = 108). There were 87.9% patients in group 1 and 82.4% in group 2 that had a familial allergic history. There were 58.6% of moderate asthma and 41.4% of severe asthma in group 1, versus 56.4% and 43.6% in group 2, respectively. The percentage of moderate and severe asthma was also significantly modified after 6th and 12th month versus at inclusion (43.1% and 35.3% versus 58.6%, P < 0.01 and P < 0.005; 23.2% and 12.9% versus 41.4%, P < 0.005 and P < 0.001, respectively). The total daily dose of ICS in group 2 at 12th months was significantly lower than that in group 1 (3515 ± 1175 versus 4785 ± 1235 mcg; P < 0.005). The daily cost of ICS treatment in group 2 was also lower than that of group 1 (18 ± 4 versus 27 ± 3 USD; P < 0.05).

CONCLUSION

The use of FE_NO in combination with GINA guidelines for ICS titration is useful in reducing the daily ICS dose and treatment cost.

Bronchoscopy in severe childhood asthma: Irresponsible or irreplaceable?

For children with severe asthma, guideline-based management focuses on the escalation of anti-inflammatory and bronchodilatory medications while addressing comorbid conditions. Bronchoscopy, in this context, has been relegated to ruling out asthma mimickers. More recently, however, there have been questions surrounding the clinical utility of bronchoscopy in severe childhood asthma. In this solicited lecture summary, we discuss the past, present, and potential future applications of bronchoscopy in severe childhood asthma.

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.

Measuring lung function in airways diseases: current and emerging techniques

Chronic airways diseases, including asthma, COPD and cystic fibrosis, cause significant morbidity and mortality and are associated with high healthcare expenditure, in the UK and worldwide. For patients with these conditions, improvements in clinical outcomes are likely to depend on the application of precision medicine, that is, the matching of the right treatment to the right patient at the right time. In this context, the identification and targeting of 'treatable traits' is an important priority in airways disease, both to ensure the appropriate use of existing treatments and to facilitate the development of new disease-modifying therapy. This requires not only better understanding of airway pathophysiology but also an enhanced ability to make physiological measurements of disease activity and lung function and, if we are to impact on the natural history of these diseases, reliable measures in early disease. In this article, we outline some of the key challenges faced by the respiratory community in the management of airways diseases, including early diagnosis, disease stratification and monitoring of therapeutic response. In this context, we review the advantages and limitations of routine physiological measurements of respiratory function including spirometry, body plethysmography and diffusing capacity and discuss less widely used methods such as forced oscillometry, inert gas washout and the multiple inert gas elimination technique. Finally, we highlight emerging technologies including imaging methods such as quantitative CT and hyperpolarised gas MRI as well as quantification of lung inhomogeneity using precise in-airway gas analysis and mathematical modelling. These emerging techniques have the potential to enhance existing measures in the assessment of airways diseases, may be particularly valuable in early disease, and should facilitate the efforts to deliver precision respiratory medicine.

Fractional Exhaled Nitric Oxide-Assisted Management of Uncontrolled Persistent Asthma: A Real-World Prospective Observational Study

CONTEXT

The utility of fractional exhaled nitric oxide (FeNO) measurement in real-world asthma management requires investigation.

OBJECTIVE

To determine whether FeNO-assisted care added to standard asthma management improves asthma control in a managed care organization.

DESIGN

Prospective observational study in patients aged 12 years and older with uncontrolled persistent asthma identified during a scheduled visit to an Allergy Department that routinely used FeNO (FeNO-assisted care, n = 426) vs visits to 4 Allergy Departments that did not, but followed routine guideline-based care (standard care, n = 925). The FeNO-assisted care was based on FeNO level, asthma control status, and step-care level.

MAIN OUTCOME MEASURES

Composite primary outcome was 1 or more asthma exacerbations or 7 or more dispensed canisters containing short-acting β2-agonists in the follow-up year. Inverse probability of treatment weighting propensity scoring balanced covariates, and multivariable regression analyses compared outcomes between groups.

RESULTS

Compared with standard care, FeNO-assisted care was not associated with reducing the primary composite outcome (adjusted risk ratio = 0.94, 95% confidence interval = 0.69-1.29, p = 0.71), nor with a reduction in asthma exacerbations or dispensing of 7 or more short-acting β2-agonist canisters as separate outcomes. In an atopic subgroup with aeroallergen sensitization, the composite outcome was similar between groups, but the rate of asthma exacerbations was lower with FeNO-assisted treatment (adjusted rate ratio = 0.67, 95% confidence interval = 0.49-0.91, p = 0.01).

CONCLUSION

These findings suggest future studies of FeNO-assisted care should be directed at the atopic phenotype.

Measurement of FeNO with a portable, electrochemical analyzer using a 6-second exhalation time in 7-10-year-old children with asthma: comparison to a 10-second exhalation

Objective: Fractional exhaled nitric oxide (FeNO) is a valuable tool for assessing Th2 inflammation in children with asthma. Exhalation times of 6 and 10 s meet the current recommendations for assessing FeNO. The 6-s exhalation provides an alternative for 7-10 year olds not able to complete the 10-s exhalation. Methods: We performed a sub-analysis on data from 7-10-year-old children who participated in a previous study which evaluated the agreement of the 6 and 10-s exhalation times in 6-10 year olds with asthma. Agreement between observed FeNO results obtained by both modes was assessed by weighted Deming regression analysis and Bland-Altman plots. Repeatability was also assessed. Results: Repeatability and agreement of the 6 and 10-s exhalations was demonstrated in 7-10 year olds with two measurements in each mode. Mean observed FeNO measurements were 33.59 ppb (SD = 25.804) for 6 s and 32.46 ppb (SD = 25.302) for 10-s exhalation. Paired differences were centered close to 0 ppb (median = 0.50). Conclusions: Children aged 7-10 years can successfully perform FeNO measurements using a portable, electrochemical FeNO analyzer. Measurements from the 6 and 10-s exhalations were repeatable and consistent with a high degree of agreement between one another. Thus, in young children successful FeNO measurements can be obtained in either the 6-s or 10-s mode, providing physicians valuable information on airway inflammation to aid in the diagnosis and treatment of asthma.

Tailoring asthma treatment on eosinophilic markers (exhaled nitric oxide or sputum eosinophils): a systematic review and meta-analysis

BACKGROUND

Asthma guidelines guide health practitioners to adjust treatments to the minimum level required for asthma control. As many people with asthma have an eosinophilic endotype, tailoring asthma medications based on airway eosinophilic levels (sputum eosinophils or exhaled nitric oxide, FeNO) may improve asthma outcomes.

OBJECTIVE

To synthesise the evidence from our updated Cochrane systematic reviews, for tailoring asthma medication based on eosinophilic inflammatory markers (sputum analysis and FeNO) for improving asthma-related outcomes in children and adults.

DATA SOURCES

Cochrane reviews with standardised searches up to February 2017.

STUDY SELECTION

The Cochrane reviews included randomised controlled comparisons of tailoring asthma medications based on sputum analysis or FeNO compared with controls (primarily clinical symptoms and/or spirometry/peak flow).

RESULTS

The 16 included studies of FeNO-based management (seven in adults) and 6 of sputum-based management (five in adults) were clinically heterogeneous. On follow-up, participants randomised to the sputum eosinophils strategy (compared with controls) were significantly less likely to have exacerbations (62 vs 82/100 participants with ≥1 exacerbation; OR 0.36, 95% CI 0.21 to 0.62). For the FeNO strategy, the respective numbers were adults OR 0.60 (95% CI 0.43 to 0.84) and children 0.58 (95% CI 0.45 to 0.75). However, there were no significant group differences for either strategy on daily inhaled corticosteroids dose (at end of study), asthma control or lung function.

CONCLUSION

Adjusting treatment based on airway eosinophilic markers reduced the likelihood of asthma exacerbations but had no significant impact on asthma control or lung function.

Exhaled nitric oxide as a guiding tool for bronchial asthma: A randomised controlled trial

Background

Evidence regarding the role of non-invasive marker of airway inflammation, fractional exhaled nitric oxide (FeNO) to guide asthma treatment is equivocal. We aimed to evaluate if the use of FeNO to adjust inhaled corticosteroid treatment resulted in reduced daily corticosteroid use and lesser exacerbations.

Methods

100 patients of bronchial asthma in the age group of 12-70 years were randomised to receive inhaled corticosteroids based on either FeNO measurements (n = 50) or as per Global Initiative for Asthma (GINA) guidelines. Follow up was done every 2 months for period of 12 months. Results were compared in terms of mean daily inhaled corticosteroid use and number of exacerbations.

Results

After the follow up period of 12 months, mean daily dose of ICS (SD) required in FeNO group was 267.5 μg (126.29), as opposed to control group in which mean daily dose of steroid was 320.00 μg (138.69). However this observed difference in steroid dose was statistically insignificant (p value = 0.061). The estimated mean (SD) rate of asthma exacerbation experienced in follow up period of 12 months in FeNO group was 0.3 episodes (0.54) per patient per year (95% confidence interval, 0.145-455) and 0.4 episodes (0.61) per patient per year in control group (95% confidence interval, 0.228-572). However this difference in rate of exacerbations between the two study groups was not statistically significant (p = 0.387).

Conclusion

FeNO guided management strategy for asthma did not result in statistically significant reduction in dose of inhaled corticosteroids or number of asthma exacerbations.

A composite of exhaled LTB4 , LXA4 , FeNO, and FEV1 as an "asthma classification ratio" characterizes childhood asthma

BACKGROUND

Aberrant generation of eicosanoids is associated with asthma, but the evidence remains incomplete and its potential utility as biomarkers is unclear. Major eicosanoids in exhaled breath condensates (EBCs) were assessed as candidate markers for childhood asthma.

METHODS

Ten exhaled eicosanoid species was evaluated using ELISA in the discovery phase, followed by prediction model-building and validation phases.

RESULTS

Exhaled LTB₄ , LTE₄ , PGE_2, and LXA₄ showed significant difference between asthmatics (N = 60) and controls (N = 20). For validation, an expanded study population consisting of 626 subjects with asthma and 161 healthy controls was partitioned into a training subset to establish a prediction model and a test sample subset for validation. Receiver operating characteristic (ROC) analyses of the training subset revealed the level of exhaled LTB₄ to be the most discriminative among all parameters, including FeNO, and a composite of exhaled LTB₄ , LXA₄ , together with FeNO and FEV₁ , distinguishing asthma with high sensitivity and specificity. Further, the Youden index (J) indicated the cut point value of 0.598 for this composite of markers as having the strongest discriminatory ability (sensitivity = 85.2% and specificity = 83.6%). The predictive algorithm as "asthma classification ratio" was further validated in an independent test sample with sensitivity and specificity being 84.4% and 84.8%, respectively.

CONCLUSIONS

In a pediatric study population in Taiwan, the levels of exhaled LTB₄ , LTE₄ , LXA_4, and PGE₂ in asthmatic children were significantly different from those of healthy controls, and the combination of exhaled LTB₄ and LXA₄ , together with FeNO and FEV₁ , best characterized childhood asthma.

Race and ethnicity have significant influence on fractional exhaled nitric oxide

BACKGROUND

Race and ethnicity have been shown to influence fractional exhaled nitric oxide (FeNO). There is a need to investigate cutoff points for different races and ethnicities to improve clinical application.

OBJECTIVE

To investigate cutoff points for different races and ethnicities by analyzing the FeNO data collected by the National Health and Nutrition Examination Survey from 2007 to 2012.

METHODS

This study included 23,433 participants. After excluding participants with confounding factors, 11,084 participants were eligible for data analysis. Based on age and the probability of having allergic airway inflammation, participants were divided into 4 groups. The geometric mean and 5th, 50th, and 95th percentiles of FeNO in Hispanic, white, black, and other races were analyzed in all groups.

RESULTS

Compared with white participants, the geometric mean for FeNO in black participants was 36% to 41% higher in children and 5% to 8% higher in adults. Hispanic children had significantly higher FeNO values (14% to 19%) compared with non-Hispanic white children; however, those differences were not significant in adults. Other races had significantly higher FeNO values in children (24-54%) and adults (9-29%) compared with white participants. Further, for normal healthy black children, the 95th percentile was 40.2 parts per billion (ppb), which is significantly higher than the cutoff point recommended by current guidelines.

CONCLUSION

Although there are significant differences in FeNO values among races and ethnicities, the current cutoff point at 50 ppb is sufficient to separate healthy from asthmatic populations in adults. However, for black children, we suggest increasing the cutoff point from 35 to 40 ppb to avoid unnecessary diagnosis and treatment.

The use of fractional exhaled nitric oxide is valuable in select asthmatic patients

PURPOSE OF REVIEW

Clinical management of asthma is challenging and measuring fractional exhaled nitric oxide (FeNO) can be another tool to assist in meeting this challenge.

RECENT FINDINGS

Asthma is a heterogeneous condition. There are many different phenotypes. FeNO can help the physician identify which patients have eosinophilic inflammation and would potentially respond to corticosteroid therapy.

SUMMARY

FeNO is a complement to standard asthma care. FeNO can be used in the initial diagnosis of asthma and aid in stratification of which patients would be steroid responsive but also for assessment of disease severity, response to treatment, and compliance.

Optimal control of asthma improved eosinophilic otitis media

Background

Eosinophilic otitis media (EOM) is often associated with comorbid asthma. The middle ear cavity is part of the upper airway. Therefore, EOM and asthma can be considered to be a crucial part of the “one airway, one disease” phenomenon. Based on the concept of one airway, one disease in the context of allergic rhinitis and asthma, optimal level of inhalation therapy for better asthma control leads to improvement in allergic rhinitis.

Objective

We conducted a pilot study to determine whether appropriate strengthening of inhalation therapy for asthma is effective for EOM.

Methods

Fifteen patients with EOM and comorbid asthma were enrolled in this study. Eight patients were randomly selected and administered appropriately strengthened inhalation therapy for asthma (strengthened group). The effect of the therapy on EOM was assessed by comparing a questionnaire for ear symptoms, clinical characteristic score, pure tone audiometry, blood tests and temporal bone computed tomography (CT) examination before and after the therapy. Seven other EOM + asthma patients without the above mentioned therapy were included as controls.

Results

In the strengthened group, the score of ear symptoms, clinical characteristics score, peripheral blood eosinophil count, CT score, and air conduction hearing level improved significantly after strengthening the inhalation therapy, but not in the control group. The lung function tests (forced vital capacity [%predicted], forced expiratory volume in 1 second [FEV₁] [L], and FEV₁ [%predicted]) significantly increased in the strengthened group after the therapy, but not in the control group.

Conclusion

In this study we demonstrated that EOM improved along with improved lung function when appropriately optimal inhalation therapy was implemented in patients with EOM and asthma. Administration of optimizing therapy for asthma might be effective for concomitant EOM.

Associations between self-rated health, sickness behaviour and inflammatory markers in primary care patients with allergic asthma: a longitudinal study

Allergic asthma is a chronic inflammatory disorder associated with elevated levels of immunoglobulin E (IgE), serum eosinophilic cationic protein (S-ECP), plasma eosinophil-derived neurotoxin (P-EDN) and fraction of exhaled nitric oxide (FENO). Poor self-rated health and sickness behaviour has repeatedly been associated with inflammatory markers, but the nature of this relationship in chronic inflammatory disease is not known. Likewise, such findings largely rely on cross-sectional investigations. Self-rated health (How would you rate your general state of health?), sickness behaviour (mean rating of satisfaction with energy, sleep, fitness, appetite and memory), IgE, S-ECP, P-EDN, and FENO were assessed in 181 non-smoking primary care patients with asthma in a 1-year longitudinal study. Associations between repeated measurements were calculated using mixed regression models and Spearman's correlations for change scores. Poor self-rated health was associated with high levels of seasonal IgE (p = 0.05) and food IgE (p = 0.04), but not total IgE or inflammatory markers. An increase over 1 year in perennial IgE was associated with a worsening of self-rated health (ρ = 0.16, p = 0.04). Poor self-rated health was associated with more pronounced sickness behaviour (p < 0.001), and a worsening in sickness behaviour was associated with a worsening of self-rated health over time (ρ = 0.21, p = 0.007). The study corroborates the importance of sickness behaviour as a determinant of self-rated health by showing that these factors co-vary over a 1-year period in a group of patients with allergic asthma. The importance of specific IgE for perceived health in primary care patients with mild to moderate asthma needs further investigation.

Longitudinal co-variations between inflammatory cytokines, lung function and patient reported outcomes in patients with asthma

Background

Asthma is a chronic inflammatory respiratory disorder associated with reduced lung function and poor quality of life. The condition is also associated with poor self-rated health, a major predictor of objective health trajectories. Of biological correlates to self-rated health, evidence suggests a role for inflammatory cytokines and related sickness behaviours. However, this is mainly based on cross-sectional data, and the relation has not been investigated in patients with chronic inflammatory conditions.

Objective

To investigate inflammatory cytokines, lung function, sickness behaviour and asthma-related quality of life as determinants of self-rated health in patients with asthma, and to investigate if these variables co-vary over time.

Methods

Plasma cytokines (IL-5, IL-6), lung function (FEV1), sickness behaviour, asthma-related quality of life and self-rated health were assessed in 181 patients with allergic asthma aged 18–64 years in a one-year longitudinal study. Mixed effect regression models and Spearman’s correlation were performed to analyse the associations between repeated measurements.

Results

More sickness behaviour and poorer asthma-related quality of life were associated with poorer self-rated health (p’s<0.001). In men, both low and high levels of interleukin (IL)-6 and poorer lung function were related with poorer self-rated health (p’s<0.05). Over the year, improved asthma-related quality of life was associated with better self-rated health (Spearman’s rho = -0.34 women,-0.36 men, p’s<0.01). Further, if sickness behaviour decreased, self-rated health improved, but only in women (Rho = -0.21, p<0.05). Increased FEV1 in men was associated with an increase in IL-6 (Rho = 0.24, p<0.05) as well as improved self-rated health (Rho = -0.21, p<0.05) and asthma-related quality of life (Rho = 0.29, p<0.01) over the year.

Conclusion

The study highlights the importance of subjectively perceived sickness behaviour and asthma-related quality of life together with lung function as determinants of self-rated health in asthmatic patients. The importance of inflammatory activation for patient reported outcomes in chronic inflammatory conditions need further investigation.

A new approach to the classification and management of airways diseases: identification of treatable traits

This review outlines a new, personalized approach for the classification and management of airway diseases. The current approach to airways disease is, we believe, no longer fit for purpose. It is impractical, overgeneralizes complex and heterogeneous conditions and results in management that is imprecise and outcomes that are worse than they could be. Importantly, the assumptions we make when applying a diagnostic label have impeded new drug discovery and will continue to do so unless we change our approach. This review suggests a new mechanism-based approach where the emphasis is on identification of key causal mechanisms and targeted intervention with treatment based on possession of the relevant mechanism rather than an arbitrary label. We highlight several treatable traits and suggest how they can be identified and managed in different healthcare settings.

High fractional exhaled nitric oxide and sputum eosinophils are associated with an increased risk of future virus-induced exacerbations: A prospective cohort study

BACKGROUND

The major trigger of asthma exacerbations is infection with a respiratory virus, most commonly rhinovirus. Type 2 inflammation is known to be associated with an increased risk of exacerbations in general. Whether type 2 inflammation at baseline increases the risk of future virus-induced exacerbations is unknown.

OBJECTIVE

To assess whether type 2 inflammation is associated with an increased risk of virus-induced exacerbations of asthma.

METHODS

Stable asthmatics had spirometry, skin prick test, measurement of FeNO and sputum induced for differential cell counts. Patients were followed up for 18 months, during which they were assessed at the research unit when they had symptoms of an exacerbation. Nasal swabs collected at these assessments underwent viral detection by PCR.

RESULTS

A total of 81 asthma patients were recruited, of which 22 (27%) experienced an exacerbation during the follow-up period. Of these, 15 (68%) had a respiratory virus detected at exacerbation. Sputum eosinophils >1% at baseline increased the risk of having a subsequent virus-induced exacerbation (HR 7.6 95% CI: 1.6-35.2, P=.010) as did having FeNO >25 ppb (HR 3.4 95% CI: 1.1-10.4, P=.033).

CONCLUSION AND CLINICAL RELEVANCE

Established type 2 inflammation during stable disease is a risk factor for virus-induced exacerbations in a real-life setting. Measures of type 2 inflammation, such as sputum eosinophils and FeNO, could be included in the risk assessment of patients with asthma in future studies.

Role of Eosinophil Granulocytes in Allergic Airway Inflammation Endotypes

Eosinophil granulocytes are intriguing members of the innate immunity system that have been considered important defenders during parasitic diseases as well as culprits during allergy-associated inflammatory diseases. Novel studies have, however, found new homoeostasis-maintaining roles for the cell. Recent clinical trials blocking different Th2 cytokines have uncovered that asthma is heterogeneous entity and forms different characteristic endotypes. Although eosinophils are present in allergic asthma with early onset, the cells may not be essential for the pathology. The cells are, however, likely disease causing in asthma with a late onset, which is often associated with chronic rhinosinusitis. Assessment of eosinophilia, fraction exhaled nitric oxide (FeNO) and periostin are markers that have emerged useful in assessing and monitoring asthma severity and endotype. Current scientific knowledge suggests that eosinophils are recruited by the inflammatory environment, activated by the innate interleukin (IL)-33 and prevented from apoptosis by both lymphocytes and innate immune cells such as type two innate immune cells. Eosinophils contain four specific granule proteins that exhibit an array of toxic and immune-modulatory activates. The granule proteins can be released by different mechanisms. Additionally, eosinophils contain a number of inflammatory cytokines and lipid mediators as well as radical oxygen species that might contribute to the disease both by the recruitment of other cells and the direct damage to supporting cells, leading to exacerbations and tissue fibrosis. This review aimed to outline current knowledge how eosinophils are recruited, activated and mediate damage to tissues and therapies used to control the cells.

Exhaled nitric oxide levels to guide treatment for children with asthma

BACKGROUND

Asthma guidelines aim to guide health practitioners to optimise treatment for patients to minimise symptoms, improve or maintain good lung function, and prevent acute exacerbations. The principle of asthma guidelines is based on a step-up or step-down regimen of asthma medications to maximise health using minimum doses. Fractional exhaled nitric oxide (FeNO) is a marker of eosinophilic inflammation and tailoring asthma medications in accordance to airway eosinophilic levels may improve asthma outcomes such as indices of control or reduce exacerbations, or both.

OBJECTIVES

To evaluate the efficacy of tailoring asthma interventions based on fractional exhaled nitric oxide (FeNO), in comparison to not using FeNO, that is, management based on clinical symptoms (with or without spirometry/peak flow) or asthma guidelines (or both), for asthma-related outcomes in children.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and reference lists of articles. The last searches were in June 2016.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing adjustment of asthma medications based on FeNO levels compared to those not using FeNO, that is, management based on clinical symptoms or asthma guidelines (or both) involving children.

DATA COLLECTION AND ANALYSIS

We reviewed results of searches against predetermined criteria for inclusion. Two review authors independently selected relevant studies, assessed trial quality and extracted data. We contacted study authors for further information with responses provided from three.

MAIN RESULTS

The review included nine studies; these studies differed in a variety of ways including definition of asthma exacerbations, FeNO cut-off levels used (12 parts per billion (ppb) to 30 ppb), the way in which FeNO was used to adjust therapy and duration of study (6 to 12 months). Of 1426 children randomised, 1329 completed the studies. The inclusion criteria for the participants in each study varied but all had a diagnosis of asthma. There was a significant difference in the number of children having one or more asthma exacerbations over the study period, they were significantly lower in the FeNO group in comparison to the control group (odds ratio (OR) 0.58, 95% confidence interval (CI) 0.45 to 0.75; 1279 participants; 8 studies). The number needed to treat for an additional beneficial outcome (NNTB) over 52 weeks was 9 (95% CI 6 to 15). There was no difference between the groups when comparing exacerbation rates (mean difference (MD) -0.37, 95% CI -0.8 to 0.06; 736 participants; 4 studies; I² = 67%). The number of children in the FeNO group requiring oral corticosteroid courses was lower in comparison to the children in the control group (OR 0.63, 95% CI 0.48 to 0.83; 1169 participants; 7 studies; I² = 0%). There was no statistically significant difference between the groups for exacerbations requiring hospitalisation (OR 0.75, 95% CI 0.41 to 1.36; 1110 participants; 6 studies; I² = 0%). There were no significant differences between the groups for any of the secondary outcomes (forced expiratory volume in one second (FEV₁), FeNO levels, symptom scores or inhaled corticosteroid doses at final visit). The included studies recorded no adverse events.Three studies had inadequate blinding and were thus considered to have a high risk of bias. However, when these studies were removed in subgroup analysis, the difference between the groups for the primary outcome (exacerbations) remained statistically significant. The GRADE quality of the evidence ranged from moderate (for the outcome 'Number of participants who had one or more exacerbations over the study period') to very low (for the outcome 'Exacerbation rates'), based on lack of blinding, statistical heterogeneity and imprecision.

AUTHORS' CONCLUSIONS

In this updated review with five new included studies, tailoring asthma medications based on FeNO levels (in comparison with primarily guideline management) significantly decreased the number of children who had one or more exacerbations over the study period but did not impact on the day-to-day clinical symptoms or inhaled corticosteroid doses. Therefore, the use of FeNO to guide asthma therapy in children may be beneficial in a subset of children, it cannot be universally recommended for all children with asthma.Further RCTs need to be conducted and these should encompass different asthma severities, different settings including primary care and less affluent settings, and consider different FeNO cut-offs.

Simultaneously elevated exhaled nitric oxide and serum-eosinophil cationic protein relate to recent asthma events in asthmatics in a cross-sectional population-based study

BACKGROUND

We have reported that increased fraction of exhaled nitric oxide (FeNO), a measure of TH₂ -driven airway inflammation, and blood eosinophil count, a marker of systemic eosinophil inflammation, correlated with asthma attacks in a population-based study.

OBJECTIVE

To investigate the relation between simultaneously elevated FeNO and serum eosinophil cationic protein (S-ECP) levels and asthma events among asthmatics.

METHODS

Measurements of FeNO (elevated ≥ 25 ppb) and S-ECP (elevated ≥ 20 ng/mL) were performed in 339 adult asthmatics. Asthma events (attacks and symptoms) were self-reported.

RESULTS

Simultaneously normal S-ECP and FeNO levels were found in 48% of the subjects. Subjects with simultaneously elevated S-ECP and FeNO (13% of the population) had a higher prevalence of asthma attacks in the preceding 3 months than subjects with normal S-ECP and FeNO (51% vs. 25%, P = 0.001). This was not found for subjects with singly elevated S-ECP (P = 0.14) or FeNO (P = 0.34) levels. Elevated S-ECP and FeNO levels were independently associated with asthma attacks in the preceding 3 months after adjusting for potential confounders (OR (95% CI) 4.2 (2.0-8.8).

CONCLUSIONS

Simultaneously elevated FeNO and S-ECP levels were related to a higher likelihood of asthma attacks in the preceding 3 months. This indicates that there is a value in measuring both FeNO and systemic eosinophilic inflammation in patients with asthma to identify individuals at high risk of exacerbations.

CLINICAL RELEVANCE

FeNO and S-ECP are markers for inflammation in asthma, but are dependent on different inflammatory pathways and weakly correlated. Simultaneous measurements of both offer better risk characterization of adult asthmatics.

Exhaled nitric oxide levels to guide treatment for adults with asthma

BACKGROUND

Asthma guidelines aim to guide health practitioners to optimise treatment for patients so as to minimise symptoms, improve or maintain good lung function, and prevent acute exacerbations or flare-ups. The principle of asthma guidelines is based on a step-up or step-down regimen of asthma medications to maximise good health outcomes using minimum medications. Asthma maintenance therapies reduce airway inflammation that is usually eosinophilic. Tailoring asthma medications in accordance with airway eosinophilic levels may improve asthma outcomes such as indices of control or reduce exacerbations or both. Fractional exhaled nitric oxide (FeNO) is a marker of eosinophilic inflammation, and as it is easy to measure, has an advantage over other measurements of eosinophilic inflammation (for example sputum eosinophils).

OBJECTIVES

To evaluate the efficacy of tailoring asthma interventions based on exhaled nitric oxide (FeNO), in comparison to not using FeNO, that is management based on clinical symptoms (with or without spirometry/peak flow) or asthma guidelines or both, for asthma-related outcomes in adults.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and reference lists of articles. The last searches were undertaken in June 2016.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing adjustment of asthma medications based on exhaled nitric oxide levels compared to not using FeNO, that is management based on clinical symptoms (with or without spirometry/peak flow) or asthma guidelines or both.

DATA COLLECTION AND ANALYSIS

We reviewed results of searches against predetermined criteria for inclusion. We independently selected relevant studies in duplicate. Two review authors independently assessed trial quality and extracted data. We contacted study authors for further information, receiving responses from four.

MAIN RESULTS

We included seven adult studies; these studies differed in a variety of ways including definition of asthma exacerbations, FeNO cutoff levels used (15 to 35 ppb), the way in which FeNO was used to adjust therapy, and duration of study (4 to 12 months). Of 1700 randomised participants, 1546 completed the trials. The mean ages of the participants ranged from 28 to 54 years old. The inclusion criteria for the participants in each study varied, but all had a diagnosis of asthma and required asthma medications. In the meta-analysis, there was a significant difference in the primary outcome of asthma exacerbations between the groups, favouring the FeNO group. The number of people having one or more asthma exacerbations was significantly lower in the FeNO group compared to the control group (odds ratio (OR) 0.60, 95% confidence interval (CI) 0.43 to 0.84). The number needed to treat to benefit (NNTB) over 52 weeks was 12 (95% CI 8 to 32). Those in the FeNO group were also significantly more likely to have a lower exacerbation rate than the controls (rate ratio 0.59, 95% CI 0.45 to 0.77). However, we did not find a difference between the groups for exacerbations requiring hospitalisation (OR 0.14, 95% CI 0.01 to 2.67) or rescue oral corticosteroids (OR 0.86, 95% CI 0.50 to 1.48). There was also no significant difference between groups for any of the secondary outcomes (FEV1, FeNO levels, symptoms scores, or inhaled corticosteroid doses at final visit).We considered three included studies that had inadequate blinding to have a high risk of bias. However, when these studies were excluded from the meta-analysis, the difference between the groups for the primary outcomes (exacerbations) remained statistically significant. The GRADE quality of the evidence ranged from moderate (for the outcome 'exacerbations') to very low (for the outcome 'inhaled corticosteroid dose at final visit') based on the lack of blinding and statistical heterogeneity. Six of the seven studies were industry supported, but the company had no role in the study design or data analyses.

AUTHORS' CONCLUSIONS

With new studies included since the last version of this review, which included adults and children, this updated meta-analysis in adults with asthma showed that tailoring asthma medications based on FeNO levels (compared with primarily on clinical symptoms) decreased the frequency of asthma exacerbations but did not impact on day-to-day clinical symptoms, end-of-study FeNO levels, or inhaled corticosteroid dose. Thus, the universal use of FeNO to help guide therapy in adults with asthma cannot be advocated. As the main benefit shown in the studies in this review was a reduction in asthma exacerbations, the intervention may be most useful in adults who have frequent exacerbations. Further RCTs encompassing different asthma severity, ethnic groups in less affluent settings, and taking into account different FeNO cutoffs are required.

Measurement of exhaled nitric oxide concentration in asthma: a systematic review and economic evaluation of NIOX MINO, NIOX VERO and NObreath

BACKGROUND

High fractions of exhaled nitric oxide (FeNO) in the breath of patients with symptoms of asthma are correlated with high levels of eosinophils and indicate that a patient is likely to respond to inhaled corticosteroids. This may have a role in the diagnosis and management of asthma.

OBJECTIVE

To assess the diagnostic accuracy, clinical effectiveness and cost-effectiveness of the hand-held electrochemical devices NIOX MINO(®) (Aerocrine, Solna, Sweden), NIOX VERO(®) (Aerocrine) and NObreath(®) (Bedfont Scientific, Maidstone, UK) for the diagnosis and management of asthma.

DATA SOURCES

Systematic searches were carried out between March 2013 and April 2013 from database inception. Databases searched included MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, Science Citation Index Expanded and Conference Proceedings Citation Index - Science. Trial registers such as ClinicalTrials.gov and the metaRegister of Controlled Trials were also searched in March 2013. All searches were updated in September 2013.

REVIEW METHODS

A rapid review was conducted to assess the equivalence of hand-held and chemiluminescent FeNO monitors. Systematic reviews of diagnostic accuracy and management efficacy were conducted. A systematic review of economic analyses was also conducted and two de novo health economic models were developed. All three reviews were undertaken according to robust high-quality methodology.

RESULTS

The rapid review (27 studies) found varying levels of agreement between monitors (Bland-Altman 95% limits of agreement up to ±10 parts per billion), with better agreement at lower FeNO values. Correlation was good (generally r > 0.9). The diagnostic accuracy review identified 22 studies in adults (all ages) and four in children. No studies used NObreath or NIOX VERO and seven used NIOX MINO. Estimates of diagnostic accuracy varied widely. FeNO used in combination with another test altered diagnostic accuracy only slightly. High levels of heterogeneity precluded meta-analysis. Limited observations included that FeNO may be more reliable and useful as a rule-in than as a rule-out test; lower cut-off values in children and in smokers may be appropriate; and FeNO may be less reliable in the elderly. The management review identified five randomised controlled trials in adults, one in pregnant asthmatics and seven in children. Despite clinical heterogeneity, exacerbation rates were lower in all studies but not generally statistically significantly so. Effects on inhaled corticosteroid (ICS) use were inconsistent, possibly because of differences in management protocols, differential effectiveness in adults and children and differences in population severity. One UK diagnostic model and one management model were identified. Aerocrine also submitted diagnostic and management models. All had significant limitations including short time horizons and the selective use of efficacy evidence. The de novo diagnostic model suggested that the expected difference in quality-adjusted life-year (QALY) gains between diagnostic options is likely to be very small. Airway hyper-responsiveness by methacholine challenge test is expected to produce the greatest QALY gain but with an expected incremental cost-effectiveness ratio (ICER) compared with FeNO (NObreath) in combination with bronchodilator reversibility of £1.125M per QALY gained. All remaining options are expected to be dominated. The de novo management model indicates that the ICER of guidelines plus FeNO monitoring using NObreath compared with guidelines alone in children is expected to be approximately £45,200 per QALY gained. Within the adult subgroup, FeNO monitoring using NObreath compared with guidelines alone is expected to have an ICER of approximately £2100 per QALY gained. The results are particularly sensitive to assumptions regarding changes in ICS use over time, the number of nurse visits for FeNO monitoring and duration of effect.

CONCLUSIONS

Limitations of the evidence base impose considerable uncertainty on all analyses. Equivalence of devices was assumed but not assured. Evidence for diagnosis is difficult to interpret in the context of inserting FeNO monitoring into a diagnostic pathway. Evidence for management is also inconclusive, but largely consistent with FeNO monitoring resulting in fewer exacerbations, with a small or zero reduction in ICS use in adults and a possible increased ICS use in children or patients with more severe asthma. It is unclear which specific management protocol is likely to be most effective. The economic analysis indicates that FeNO monitoring could have value in diagnostic and management settings. The diagnostic model indicates that FeNO monitoring plus bronchodilator reversibility dominates many other diagnostic tests. FeNO-guided management has the potential to be cost-effective, although this is largely dependent on the duration of effect. The conclusions drawn from both models require strong technical value judgements with respect to several aspects of the decision problem in which little or no empirical evidence exists. There are many potential directions for further work, including investigations into which management protocol is best and long-term follow-up in both diagnosis and management studies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013004149.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Important non-disease-related determinants of exhaled nitric oxide levels in mild asthma - results from the Swedish GA(2) LEN study

BACKGROUND

Fractional exhaled nitric oxide (FeNO) has a potential clinical role in asthma management. Constitutive factors such as age, height and gender, as well as individual characteristics, such as IgE sensitization and smoking, affect the levels of FeNO in population-based studies. However, their effect on FeNO in subjects with asthma has been scarcely studied.

OBJECTIVE

To study the effects on FeNO of these commonly regarded determinants, as demonstrated in healthy subjects, as well as menarche age and parental smoking, in a population of asthmatics.

MATERIAL AND METHODS

Fractional exhaled nitric oxide was measured in 557 subjects with asthma from the Swedish GA(2) LEN study. Allergic sensitization was assessed by skin prick tests to most common aeroallergens. Upper airway comorbidities, smoking habits, smoking exposure during childhood and hormonal status (for women) were questionnaire-assessed.

RESULTS

Male gender (P < 0.001), greater height (P < 0.001) and sensitization to both perennial allergens and pollen (P < 0.001) are related to higher FeNO levels. Current smoking (P < 0.001) and having both parents smoking during childhood, vs. having neither (P < 0.001) or only one parent smoking (P = 0.002), are related to lower FeNO. Women with menarche between 9 and 11 years of age had lower FeNO than those with menarche between 12 and 14 years of age (P = 0.03) or 15 and 17 years of age (P = 0.003).

CONCLUSIONS AND CLINICAL RELEVANCE

Interpreting FeNO levels in clinical practice is complex, and constitutional determinants, as well as smoking and IgE sensitisation, are of importance in asthmatic subjects and should be accounted for when interpreting FeNO levels. Furthermore, menarche age and parental smoking during childhood and their effects on lowering FeNO deserve further studies.

Exhaled nitric oxide in relation to asthma control: A real-life survey

BACKGROUND

Asthma is characterised by chronic airway inflammation, a complex cascade of events, mostly sustained by eosinophil recruitment and activation. Fractional exhaled nitric oxide (FeNO) is a surrogate marker of airway inflammation closely associated with bronchial eosinophilia. FeNO is used to define asthma phenotype, to assess eosinophilic inflammatory severity and to predict corticosteroid responsiveness.

OBJECTIVE

The aim of this study was to investigate whether FeNO may be associated with some clinical and functional factors in asthmatics evaluated in a real life setting.

METHODS

Globally 363 patients (150 males, mean age 46.3 years) with asthma were consecutively evaluated. The following parameters were assessed: history, including comorbidities, physical examination, body mass index (BMI), lung function, asthma control grade, asthma control test (ACT), and FeNO.

RESULTS

FeNO values were significantly higher in patients with poorly controlled asthma (p<0.01), asthma symptoms (p=0.015), wheezing (p<0.001), rhinitis diagnosis, (p=0.049) and rhinitis symptoms (p=0.019), but lower in patients with GERD (p=0.024) and pneumonia history (p=0.048). FeNO values increased in patients with the lowest corticosteroid dose (p=0.031). FeNO values>25ppb were associated with poorly controlled asthma (OR 3.71), asthma signs (OR 3.5) and symptoms (OR 1.79). A FeNO value cut-off of 29.9ppb was fairly predictive of (AUC 0.7) poorly controlled asthma.

CONCLUSIONS

FeNO assessment in clinical practice may be a useful tool for monitoring asthmatics as it is associated with several clinical factors, including asthma control.

Parallel reductions of IgE and exhaled nitric oxide after optimized anti-inflammatory asthma treatment

Immunoglobulin E (IgE) is crucial for the development of airway inflammation in atopic asthma, and inhibition of IgE using monoclonal antibodies is now part of asthma therapy. However, the impact of ordinary anti-inflammatory treatment on IgE is unclear. The aim of this study was to investigate if optimization of treatment with inhaled corticosteroid (ICS) and leukotriene-receptor antagonist (LTRA) according to symptoms or exhaled nitric oxide (F_ENO) levels over a one-year period affects IgE concentrations. Altogether, 158 relatively well-controlled but multi-sensitized asthmatics (age 18-65 years), with ongoing ICS treatment at baseline, were included in this post hoc analysis of data from a randomized, controlled trial on F_ENO-guided asthma therapy. Asthma control and quality of life (Juniper ACQ and mAQLQ), F_ENO, and serum IgE were measured at baseline and after one year. Concentrations of IgE antibodies to six common perennial aeroallergens were summed up (perennial IgE). We found that perennial and total IgE decreased by 10.2% and 16.0% (P < .001 both comparisons). This was not related to allergen exposure, whereas the total use of ICS and LTRA during the year correlated with the reduction in perennial IgE (P = .030 and P = .013). The decrease in perennial and total IgE correlated significantly with the reduction in F_ENO (P < .003 and P < .001), and with improvements in ACQ and mAQLQ scores (P < 0.05, all comparisons). We conclude that one year of optimization of treatment with ICS and LTRA in patients with persistent atopic asthma resulted in significant decreases in total IgE and IgE antibodies; these decreases correlated with a reduction in F_ENO and improvements in asthma control and quality of life. Thus, IgE is reduced by ordinary asthma controller medications and the effect on IgE seems to be clinically important.

Fractional exhaled nitric oxide for the management of asthma in adults: a systematic review

The aim of this review was to evaluate the clinical effectiveness of fractional exhaled nitric oxide (FeNO) measured in a clinical setting for the management of asthma in adults.13 electronic databases were searched and studies were selected against predefined inclusion criteria. Quality assessment was conducted using QUADAS-2. Class effect meta-analyses were performed.Six studies were included. Despite high levels of heterogeneity in multiple study characteristics, exploratory class effect meta-analyses were conducted. Four studies reported a wider definition of exacerbation rates (major or severe exacerbation) with a pooled rate ratio of 0.80 (95% CI 0.63-1.02). Two studies reported rates of severe exacerbations (requiring oral corticosteroid use) with a pooled rate ratio of 0.89 (95% CI 0.43-1.72). Inhaled corticosteroid use was reported by four studies, with a pooled standardised mean difference of -0.24 (95% CI -0.56-0.07). No statistically significant differences for health-related quality of life or asthma control were found.FeNO guided management showed no statistically significant benefit in terms of severe exacerbations or inhaled corticosteroid use, but showed a statistically significant reduction in exacerbations of any severity. However, further research is warranted to clearly define which management protocols (including cut-off points) offer best efficacy and which patient groups would benefit the most.

A pathophysiological approach for FeNO: A biomarker for asthma

The present review is focused on literature concerning the relevance of fractional exhaled nitric oxide (FeNO) in clinical practice from a pathophysiological point of view. There is increasing evidence that asthma is a heterogeneous pathological condition characterised by different phenotypes/endotypes related to specific biomarkers, including FeNO, helpful to predict therapeutic response in selected asthmatic populations. Nowadays FeNO, a non-invasive biomarker, appears to be useful to foresee asthma developing, to recognise specific asthma phenotypes, like the eosinophilic, to ameliorate asthma diagnosis and management in selected populations and to predict standard corticosteroid and biologic therapy efficacy. In addition, FeNO assessment may also be useful in patients with allergic rhinitis in order to detect the potential involvement of eosinophilic bronchial inflammation in "case finding" subjects at risk of asthma diagnosis. Therefore, it is possible to hypothesise a future with an appropriate use of FeNO by physicians dealing with worrisome clinical issues in specific asthma phenotypes.

Impact of exhaled nitric oxide measurements on treatment decisions in an asthma specialty clinic

BACKGROUND

Asthma management in an outpatient setting is best accomplished by clinical evaluation coupled with spirometry and symptom evaluation, but these assessments do not provide information about airway inflammation. Exhaled nitric oxide (fraction of exhaled nitric oxide [FeNO]) measures T-helper cell type 2-mediated airway inflammation and may be a useful adjunct in asthma management.

OBJECTIVE

To determine whether the use of FeNO in the specialist management of asthma results in more effective and cost-effective treatment decisions.

METHODS

Fifty subjects 7 to 60 years old with established asthma participated in this observational study. Subjects were evaluated by clinical examination, spirometry, and symptom assessment using the Asthma Control Test, and clinicians estimated airway inflammation and made treatment decisions based on these assessments. Then, FeNO was measured, and changes in therapy based on FeNO levels were documented. The estimated cost impact of using FeNO was calculated presuming ongoing FeNO use in patient management.

RESULTS

Without FeNO, the clinician's assessment of airway inflammation was incorrectly classified in 50% of subjects. FeNO results substantially altered treatment decisions in more than one third of subjects, notably medication augmentation in 10 (20%) and medication decreases in 8 (16%). Use of FeNO in addition to standard of care was estimated to save $629 per subject per year.

CONCLUSION

Measurement of FeNO augments routine clinical assessment of asthma by measuring airway inflammation. Knowledge of FeNO affects medication treatment decisions to augment or decrease pharmacotherapy, which has important long-term asthma management implications, most notably the potential to lower the costs and morbidity associated with asthma exacerbation.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01729247.

Characterization of airway inflammation in patients with COPD using fractional exhaled nitric oxide levels: a pilot study

Objective

To characterize fractional exhaled nitric oxide (FeNO) levels that may be indicative of Th2-mediated airway inflammation in patients with chronic obstructive pulmonary disease (COPD).

Methods

This single-visit, outpatient study was conducted in 200 patients aged 40 years and older with COPD. All patients underwent spirometry and FeNO testing. COPD severity was classified according to the Global initiative for chronic Obstructive Lung Disease (GOLD) 2010 guidelines.

Results

Patients who participated in the study had a mean age of 63.9±11.3 years and a mean smoking history of 46±29 pack years. Patients had a mean forced expiratory volume in 1 second % predicted of 53.9%±22.1%. The percentage of patients classified with COPD severity Stage I, II, III, and IV was 13%, 40%, 39%, and 8%, respectively. In addition, according to current procedural terminology codes, 32% of patients were classified as mixed COPD/asthma, 26% as COPD/emphysema, and 42% as all other codes. The mean FeNO level for all patients was 15.3±17.2 parts per billion (ppb). Overall, 89% of patients had a FeNO <25 ppb, 8% had a FeNO 25–50 ppb, and 3% had a FeNO >50 ppb. The percentages of patients with FeNO in the intermediate or high ranges of FeNO were greatest among patients with mixed COPD/asthma (intermediate, 11.5%; high, 6.6%) compared with COPD/emphysema (intermediate, 8%; high, 0) and all other codes (intermediate, 6.3%; high, 1.3%).

Conclusion

Increases in FeNO were identified in a subset of patients with COPD, particularly in those previously diagnosed with both COPD and asthma. Since FeNO is useful for identifying patients with airway inflammation who will have a beneficial response to treatment with an inhaled corticosteroid, these data may have important implications for the management of COPD patients.

Current evidence and future research needs for FeNO measurement in respiratory diseases

Although not yet widely implemented, fraction of exhaled nitric oxide (FeNO) has emerged in recent years as a potentially useful biomarker for the assessment of airway inflammation both in undiagnosed patients with non-specific respiratory symptoms and in those with established airway disease. Research to date essentially suggests that FeNO measurement facilitates the identification of patients exhibiting T-helper cell type 2 (Th2)-mediated airway inflammation, and effectively those in whom anti-inflammatory therapy, particularly inhaled corticosteroids (ICS), is beneficial. In some studies, FeNO-guided management of patients with established airway disease is associated with lower exacerbation rates, improvements in adherence to anti-inflammatory therapy, and the ability to predict risk of future exacerbations or decline in lung function. Despite these data, concerns regarding the applicability and utility of FeNO in clinical practice still remain. This article reviews the current evidence, both supportive and critical of FeNO measurement, in the diagnosis and management of asthma and other inflammatory airway diseases. It additionally provides suggestions regarding the practical application of FeNO measurement: how it could be integrated into routine clinical practice, how its utility could be assessed and its true value to both clinicians and patients could be established. Although some unanswered questions remain, current evidence suggests that FeNO is potentially a valuable tool for improving the personalised management of inflammatory airway diseases.