Relations between exhaled nitric oxide and measures of disease activity among children with mild-to-moderate asthma

Association of Sputum Eosinophilia With Easily Measured Type-2 Inflammatory Biomarkers in Untreated Mild Persistent Asthma

BACKGROUND

A multicenter clinical trial in patients with mild persistent asthma indicated that response to inhaled corticosteroids (ICS) is limited to those with sputum eosinophilia. However, testing for sputum eosinophilia is impractical in most clinical settings.

OBJECTIVE

We examined associations between sputum eosinophilia and type 2 inflammatory biomarkers in untreated mild persistent asthma.

METHODS

Induced sputum, blood eosinophil count (BEC), fractional exhaled nitric oxide (FeNO), and serum periostin were obtained twice during the 6-week run-in period in a clinical trial that enrolled patients 12 years and older with symptomatic, mild persistent asthma without controller therapy. The optimal threshold for each biomarker was based on achieving 80% or greater sensitivity. Performance of biomarkers (area under the receiver operating characteristics curve [AUC], range 0.0-1.0) in predicting sputum eosinophilia 2% or greater was determined; AUCs of 0.8 to 0.9 and more than 0.9 define excellent and outstanding discrimination, respectively.

RESULTS

Of 564 participants, 27% were sputum eosinophilic, 83% were atopic, 70% had BEC of 200/uL or higher or FeNO of 25 ppb or greater; 64% of participants without sputum eosinophilia had elevated BEC or FeNO. The AUCs for BEC, FeNO, and both together in predicting sputum eosinophilia were all below the threshold for excellent discrimination (AUC 0.75, 0.78, and 0.79, respectively). Periostin (in adults) had poor discrimination (AUC 0.59; P = .02).

CONCLUSIONS

In untreated mild persistent asthma, there is substantial discordance between sputum eosinophilia, BEC, and FeNO. Until prospective trials test the ability of alternative biomarkers to predict ICS response, BEC or FeNO phenotyping may be an option to consider ICS through a shared decision-making process with consideration of other clinical features.

Assessment of Fraction of Exhaled Nitric Oxide and Soluble Receptor for Advanced Glycation End Products Biomarkers for Jordanian Asthmatic Children

PURPOSE

Fraction of exhaled nitric oxide (FeNO) and soluble advanced glycation end-product receptor (sRAGE) are proposed as biomarkers of asthma, therefore we sought to assess their use in asthmatic children of Jordan.

PATIENTS AND METHODS

We conducted a case-control study at The University of Jordan Hospital. A total of 141 asthmatic children followed by respiratory pediatricians and 118 healthy children aged 4-18 years were recruited. FeNO was measured by NObreath device and serum sRAGE by ELISA that detect endogenously soluble isoform (esRAGE) and total soluble RAGE (sRAGE).

RESULTS

sRAGE in asthmatic was half of the control (p <0.001). In addition, ratio of esRAGE/sRAGE was two-fold higher in asthmatic (p = <0.001). Neither FeNO nor esRAGE levels were significantly different between groups. FeNO and asthma control test (ACT) score were negatively correlated corrected for age and body mass index (BMI), (r = -0.180, p= 0.034). For the uncontrolled asthma group, esRAGE/sRAGE negatively correlated with ACT score (r = -.329, p = 0.038). Receiver operating curve (ROC) analysis revealed significant predictive value (PV) for sRAGE and esRAGE/sRAGE in asthma detection with area under the curve (AUC) of (0.751 ± 0.031) and (0.711±.033), consequently. However, no biomarker had a significant PV for lack of control.

CONCLUSION

The current study supports utilizing sRAGE as a marker for asthma and present a potential therapeutic target. However, our results indicate that both FeNO and sRAGE have a limited role in the management of asthmatic children or assessment of asthma control.

Advances in the pathogenesis and personalised treatment of paediatric asthma

The diversity of pathology of severe paediatric asthma demonstrates that the one-size-fits-all approach characterising many guidelines is inappropriate. The term "asthma" is best used to describe a clinical syndrome of wheeze, chest tightness, breathlessness, and sometimes cough, making no assumptions about underlying pathology. Before personalising treatment, it is essential to make the diagnosis correctly and optimise basic management. Clinicians must determine exactly what type of asthma each child has. We are moving from describing symptom patterns in preschool wheeze to describing multiple underlying phenotypes with implications for targeting treatment. Many new treatment options are available for school age asthma, including biological medicines targeting type 2 inflammation, but a paucity of options are available for non-type 2 disease. The traditional reliever treatment, shortacting β2 agonists, is being replaced by combination inhalers containing inhaled corticosteroids and fast, longacting β2 agonists to treat the underlying inflammation in even mild asthma and reduce the risk of asthma attacks. However, much decision making is still based on adult data extrapolated to children. Better inclusion of children in future research studies is essential, if children are to benefit from these new advances in asthma treatment.

Knockdown of miR‑205‑5p alleviates the inflammatory response in allergic rhinitis by targeting B‑cell lymphoma 6

Allergic rhinitis (AR) is an IgE-mediated upper airway disease with a high worldwide prevalence. MicroRNA (miR)-205-5p upregulation has been observed in AR; however, its role is poorly understood. The aim of the present study was to investigate the effect of miR-205-5p on AR-associated inflammation. To establish an AR model, BALB/c mice were sensitized using an intraperitoneal injection of ovalbumin (OVA) on days 0, 7 and 14, followed by intranasal challenge with OVA on days 21–27. A lentiviral sponge for miR-205-5p was used to downregulate miR-205-5p in vivo via intranasal administration on days 20–26. Reverse transcription-quantitative PCR revealed that miR-205-5p was upregulated in AR mice. Notably, miR-205-5p knockdown reduced the frequency of nose-rubbing and sneezing, and attenuated pathological alterations in the nasal mucosa. The levels of total and OVA-specific IgE, cytokines IL-4, IL-5 and IL-13, and inflammatory cells, were decreased by miR-205-5p knockdown in AR mice. In addition, miR-205-5p knockdown inhibited nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation by reducing the expression levels of NLRP3, apoptosisassociated specklike protein containing a CARD, cleaved caspase-1 and IL-1β by western blot analysis. B-cell lymphoma 6 (BCL6) was confirmed as a target of miR-205-5p by luciferase reporter assay. In conclusion, the present findings suggested that miR-205-5p knockdown may attenuate the inflammatory response in AR by targeting BCL6, which may be a potential therapeutic target for AR.

"Poor Effort" Does Not Account for Reduced Forced Vital Capacity in Asthmatic Children

Purpose: Poor forced vital capacity (FVC) effort has been considered to be the main reason for FVC reduction by the ATS/ERS guideline; however, this has rarely been mentioned in previous studies. The present study aims to determine whether reduced FVC in asthmatic children is correlated to poor FVC effort. Methods: A total of 209 asthmatic children within 5-13 years old were included and divided into reduced FVC ("restricted," n = 66) and typical obstruction group ("obstructed," n = 143). Forced expiratory flows before and after bronchodilation were recorded in asthmatic children. The differences in clinical characteristics, spirometric results, FVC effort, and bronchodilator response were compared between two groups. Exhalation time (ET) was divided into effective ET (ETe) and plateau ET (ETp) by the start point of exhalation plateau on the time-volume curve. FVC effort was assessed by ET, ETp, and back extrapolated volume (EV)/FVC (%). Results: Asthmatic children in the restricted group had significantly higher slow vital capacity (SVC)/FVC (%), higher EV/FVC (%), shorter ET, shorter ETe, and longer ETp, when compared with those with obstructed. In the obstructed group, ET (r = 0.201, P = 0.016) and ETe (r = 0.496, P < 0.001) positively correlated with FVC, and ETp (r = -0.224, P = 0.007) negatively correlated with FVC. In the restricted group, FVC positively correlated with ETe (r = 0.350, P = 0.004) but not ET and ETp. FVC z-score significantly correlated with total IgE (n = 51, r = -0.349, P = 0.012) and with FEF_25-75% z-score (n = 66, r = 0.531, P < 0.001) in the restricted group. The further logistic regression revealed that the risk of restricted increased by 1.12 (95% CI, 1.04-1.22, P = 0.005) with every 1% increase in %ΔFVC. In subjects with restricted and bronchodilation tests, %ΔFVC was significantly associated with FeNO (n = 29, r = 0.386, P = 0.039), FEF_25-75% z-score (n = 29, r = -0.472, P = 0.010), and SVC/FVC (%) (n = 19, r = 0.477, P = 0.039) but not with EV/FVC (%), ET, ETe, or ETp (P > 0.05). Conclusion: These findings suggested that "poor FVC effort" does not account for the FVC reduction in asthmatic children. Short ET and high SVC/FVC (%) are characteristics of reduced FVC.

Evaluation of Fractional Exhaled Nitric Oxide in Pediatric Asthma and Allergic Rhinitis

Fractional exhaled nitric oxide (FeNO) is a non-invasive test for evaluating the degree of airway inflammation and for the diagnosis, evaluation, and treatment of asthma. We attempted to measure FeNO levels in Korean children with asthma and determine its cutoff value for diagnosing asthma. We enrolled 176 children and adolescents between the ages of 5 and 18 years, who visited for the evaluation of chronic cough, shortness of breath, and wheezing. Among them, 138 patients who underwent skin prick tests or inhalation Immuno CAP (UniCAP; Pharmacia, Uppsala, Sweden) tests for allergy testing together with a pulmonary function test were included. FeNO was measured using a NIOX MINO (Aerocrine AB, Solna, Sweden) instrument according to the American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines. There were 29 patients with asthma, 43 with rhinitis, and 38 with asthma and allergic rhinitis. In the asthma group, FeNO levels significantly correlated with total immunoglobulin E (r = 0.572, p < 0.001), but did not show significant correlation with pulmonary function test parameters (forced vital capacity—FVC, forced expiratory volume in one second—FEV1, FEV1/FVC) or PC20 (provocative concentration of methacholine causing a 20% fall in FEV1). The FeNO cutoff values obtained in the asthma and asthma rhinitis groups were 16.5 ppb and 18.5 ppb, respectively. Hence, we provide a FeNO cutoff value according to the presence or absence of rhinitis in pediatric patients with asthma.

Usefulness of extended nitric oxide analysis in children with allergic rhinitis

OBJECTIVE

Evaluation of airway inflammation and dysfunction is important in management of allergic rhinitis (AR) since AR is a risk factor for developing asthma. Theoretical nonlinear modeling of exhaled nitric oxide (NO) has revealed extended flow-independent NO parameters that could explain where or how NO metabolism was altered. We aimed to evaluate the association between extended NO parameters and bronchial hyperresponsiveness (BHR) in children with AR.

METHODS

Exhaled NO was measured in 74 children with AR on the same day they underwent the provocholine challenge test (PCT). Extended NO was measured in three different exhaled flow rates (30, 100, 200 mL/s) and calculated using the Högman-Meriläinen model. We compared the extended NO parameters including bronchial NO (JawNO), airway tissue NO (CawNO), alveolar tissue NO (CaNO), and diffusing capacity of NO (DawNO) between AR with and without BHR groups, and analyzed the correlation between extended NO parameters and the response-dose ratio (RDR) of the PCT. We additionally evaluated 49 respiratory healthy controls.

RESULTS

Among the 74 children with AR, nine showed BHR. JawNO increased more in children with AR than the control group. In children with AR, JawNO was higher in the AR with BHR than without BHR group, and was correlated positively with log RDR (r = 0.373, p = .001).

CONCLUSIONS

Extended NO analysis including JawNO can be a useful tool for assessing BHR in AR.

Change in capnogram waveform is associated with bronchodilator response and asthma control in children

BACKGROUND

Airway hyper-reactivity, inflammation and remodeling contribute to inhomogeneity of ventilation-perfusion ratio VA·/Q· in asthma. Short-term variations in V.A/Q· can cause changes in expired capnographic indices.

OBJECTIVES

To measure acute changes in the phase 3 slope of the volumetric capnogram after β2-agonist inhalation (ΔSIII), for comparison with airway response based on FEV1 (ΔFEV1), and asthma control.

SUBJECTS AND METHODS

After ethical approval and informed consent, 72 children aged 6-18 y, followed up for asthma underwent spirometry and capnography before and after β-agonist inhalation through a spacer, using a side-stream rapid infrared analyzer. Asthma control was assessed using the GINA questionnaire.

RESULTS

Children with positive reversibility tests (defined as ΔFEV1>12%) had a significantly higher ΔSIII (m ± SE: 87.4 ± 41.4) versus those with negative tests (31.3 ± 14.0%, P = 0.001). Uncontrolled asthma was associated with a significantly larger ΔSIII (103.4 ± 64.0%, n = 7) compared to partly controlled (52.0 ± 26.1, n = 24; P = 0.009) and controlled asthma (30.8 ± 16.3, n = 41; P = 0.003). Neither Bohr dead space nor ΔFEV1 were different between asthma control groups.

CONCLUSIONS

ΔSIII was significantly larger in children with positive response to β2-agonist, and in uncontrolled asthmatics. To our knowledge these are the first data on exhaled CO₂ phase III volumetric slope change and asthma control. The observed ΔSIII could be due to an increased ventilation of inhomogeneous peripheral lung units, and merits further evaluation as a potential phenotypic biomarker in asthma.

Measuring Airway Inflammation in Asthmatic Children

Asthma is the most common chronic respiratory disease in children characterized by airways inflammation, bronchial hyperresponsiveness, recurrent reversible airways obstruction, and respiratory symptoms. The diagnosis of the disease is based on clinical history, airways obstruction at spirometry, and bronchial reversibility. Asthma treatment is aimed to disease control, through the use of controller treatment and monitoring lung function. However, lung function and symptoms not always reflect the underlying airways inflammation and response to the therapy. Objective parameters of asthma inflammation could be important for the clinician in the management of patients with asthma. In the last years, some studies were focused on biomarkers to identify phenotype, inflammation, and pathobiological pathways to help the clinician in the diagnosis and in personalizing the management. Accordingly, clinically feasible tests are represented by the collection of exhaled breath condensate (EBC) and measurement of exhaled nitric oxide (FeNO). Other-methods such as the evaluation of volatile organic compound (VOCs), that reflect airways inflammation and treatment efficacy, are currently used for research purposes For some of these methods, The lack of standardization in pre-collection, collection, post-collection of samples, and interpretation of the results may a problem in clinical practice. Improved these limitations, several biomarkers will be useful to distinguish patients with a different disease condition to personalize the treatment.

Severe Asthma in Children

PURPOSE OF REVIEW

The aim of this study is to characterize, diagnose, evaluate, and treat severe childhood asthma.

RECENT FINDINGS

Understanding the occurrence of the physiologic and clinical presentations of childhood severe asthma, the treatment and response may be predicted by biomarkers, but the patient's response is highly variable. The onset of severe asthma occurs early and is primarily predicted by severity of viral infection and coexistence of the atopic state.

Biomarkers for the Phenotyping and Monitoring of Asthma in Children

An important issue in relation to the utility and reliability of biomarkers for asthma monitoring is how asthma is defined and characterized. What kind of asthma, or at what stage of the disease is a particular biomarker supposed to add information? Often, the purpose, or usefulness of a biomarker is not made clear. Diagnosis, severity evaluation, and monitoring are all different clinical uses for a biomarker, and confusion may arise when a biomarker is suitable for one of these but not another. When the utility of available biomarkers are discussed, these different roles need to be clarified. Our opinion is that there are four aspects of relevance to asthma, for which biomarkers are required: to diagnose allergies, to evaluate inflammation in the airways, to evaluate hyper-responsiveness, and for certain measures of lung function, such as lung clearance index. These types of biomarkers are needed for the phenotyping and monitoring of asthma. Another important role for biomarkers is, as mentioned above, to monitor asthma in order to follow treatment effects on inflammation and hyper-responsiveness as objective adjuncts to the patients' own symptom reports and lung function. This review will mainly focus on biomarkers that reflect airway inflammation. In spite of the numerous studies that have been conducted, we still have to remember that the value of biomarkers available for routine use, such as eosinophil counts in blood and sputum and exhaled nitric oxide, have to be interpreted in relation to reported symptoms and lung function. Measures of bronchial hyper-responsiveness, performed either by direct (methacholine challenge) or indirect (exercise or mannitol challenge) methods, could be considered biomarkers but will not be included in this review. On the other hand, diagnosing allergy is not usually useful for monitoring asthma although it is of fundamental importance for the interpretation of most biomarkers that are suitable for monitoring. We have therefore included the different approaches for diagnosing and evaluating allergic sensitization in this review.

[Research progress in relationship between fractional exhaled nitric oxide and asthma in children]

Bronchial asthma is a heterogeneous disease that is characterized by airway hyperresponsiveness and chronic inflammation. It is often accompanied by reversible airflow obstruction. Current laboratory testing methods for the diagnosis of asthma in children mainly include lung ventilation function test. Due to the non-cooperation of children, it is very challenging to conduct lung ventilation function test for preschoolers. Lung function testing is an instantaneous indicator, which is influenced by the children's understanding ability and mental factors. In addition, it could not assess the severity of airway inflammation. Fractional exhaled nitric oxide (FeNO) is a noninvasive, simple, and objective indicator of airway inflammation and has gradually gained increased use in children in recent years. This review article introduces the source of FeNO, the reference value of FeNO in laboratory testing, and the progress in the application of FeNO in the diagnosis, prediction, and treatment of asthma in children of various ages.

Monitoring asthma in childhood: lung function, bronchial responsiveness and inflammation

This review focuses on the methods available for measuring reversible airways obstruction, bronchial hyperresponsiveness (BHR) and inflammation as hallmarks of asthma, and their role in monitoring children with asthma. Persistent bronchial obstruction may occur in asymptomatic children and is considered a risk factor for severe asthma episodes and is associated with poor asthma outcome. Annual measurement of forced expiratory volume in 1 s using office based spirometry is considered useful. Other lung function measurements including the assessment of BHR may be reserved for children with possible exercise limitations, poor symptom perception and those not responding to their current treatment or with atypical asthma symptoms, and performed on a higher specialty level. To date, for most methods of measuring lung function there are no proper randomised controlled or large longitudinal studies available to establish their role in asthma management in children. Noninvasive biomarkers for monitoring inflammation in children are available, for example the measurement of exhaled nitric oxide fraction, and the assessment of induced sputum cytology or inflammatory mediators in the exhaled breath condensate. However, their role and usefulness in routine clinical practice to monitor and guide therapy remains unclear, and therefore, their use should be reserved for selected cases.

A systematic review of fractional exhaled nitric oxide in the routine management of childhood asthma

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of eosinophilic inflammation which may be used to guide the management of asthma in childhood.

OBJECTIVES

To synthesise the available evidence on the efficacy of FeNO-guided management of childhood asthma.

METHODS

Databases including MEDLINE and the Cochrane Library were searched, and randomised controlled trials (RCTs) comparing FeNO-guided management with any other monitoring strategy were included. Study quality was assessed using the Cochrane risk of bias tool for RCTs, and a number of outcomes were examined, including: exacerbations, medication use, quality of life, adverse events, and other markers of asthma control. Meta-analyses were planned if multiple studies with suitable heterogeneity were available. However, due to wide variations in study characteristics, meta-analysis was not possible.

RESULTS

Seven RCTs were identified. There was some evidence that FeNO-guided monitoring results in improved asthma control during the first year of management, although few results attained statistical significance. The impact on severe exacerbations was unclear. Similarly, the impact on use of anti-asthmatic drugs was unclear, and appears to depend on the step up/down protocols, and the clinical characteristics of patients.

CONCLUSIONS

The potential benefit of FeNO monitoring is equivocal. Trends toward reduced exacerbation and increased medication use were seen, but typically failed to reach statistical significance. There are a number of issues that complicate data interpretation, including differences in the likely severity of included cohorts and variations in treatment algorithms. Further work is needed to systematically explore the impact of these parameters.

Bronchodilator response as a marker of poor asthma control

BACKGROUND

Asthma guidelines emphasise the importance of monitoring disease control in managing asthma.

OBJECTIVE

The aim of this study was to evaluate the relationship between lung function, including bronchodilator response in terms of improving in FEV1 after administration of salbutamol, and asthma control.

METHODS

246 patients with known asthma and in regular chronic treatment according to international guidelines were consecutively enrolled in a 12 month-period. All patients were evaluated by asthma control test (ACT), spirometry and bronchodilator test with salbutamol 400 mcg.

RESULTS

Mean ACT value was 18.8. Patients with significant bronchial reversibility had lower ACT mean values. This finding was confirmed in both patients with airway obstruction and in those with normal spirometry. There was a significant correlation between ACT values and bronchodilator response.

CONCLUSIONS

The persistence of a significant degree of bronchodilator response despite regular treatment according to guidelines was a marker of worse asthma control.

CLINICAL IMPLICATIONS

Bronchodilator response, correlating with worse asthma control even in patients with normal spirometry, should be test at every visit as it may add information on asthma control.

Serum periostin levels correlate with airway hyper-responsiveness to methacholine and mannitol in children with asthma

BACKGROUND

Periostin is a matricellular protein, and its synthesis in airway epithelial cells and lung fibroblasts is induced by interleukin (IL)-4 and IL-13. The significance of periostin as a biomarker of TH 2-induced airway inflammation, and (importantly) as a measure of the response to TH 2-targeted therapy, has recently been emphasized. We explored the relationship between periostin and airway hyperresponsiveness (AHR) in asthmatic children.

METHODS

The study included 83 children aged 6-15 years in an asthmatic group (n = 54) and healthy controls (n = 29). We measured the periostin levels in serum and performed methacholine and mannitol provocation challenges. The responses to mannitol were expressed as the provocative dose causing a 15% fall in the FEV1 (the PD15 dose).

RESULTS

Of the 54 subjects with asthma, all had positive methacholine bronchial provocation test (BPT) results and 38 had positive mannitol BPT results. Children with asthma had significantly higher periostin levels than controls [76.0 (65.0-91.8) vs 71.0 (57.5-80.0) ng/mL; P = 0.017]. Periostin levels were significantly correlated with both the methacholine PC20 and mannitol PD15 values.

CONCLUSION

Serum levels of periostin, a new biomarker induced by IL-13, were higher in asthmatic children, and were associated with AHR to methacholine and mannitol.

Inhaled corticosteroids in children with persistent asthma: dose-response effects on growth

BACKGROUND

Inhaled corticosteroids (ICS) are the first-line treatment for children with persistent asthma. Their potential for growth suppression remains a matter of concern for parents and physicians.

OBJECTIVES

To assess whether increasing the dose of ICS is associated with slower linear growth, weight gain and skeletal maturation in children with asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov website up to March 2014.

SELECTION CRITERIA

Studies were eligible if they were parallel-group randomised trials evaluating the impact of different doses of the same ICS using the same device in both groups for a minimum of three months in children one to 17 years of age with persistent asthma.

DATA COLLECTION AND ANALYSIS

Two review authors ascertained methodological quality independently using the Cochrane Risk of bias tool. The primary outcome was linear growth velocity. Secondary outcomes included change over time in growth velocity, height, weight, body mass index and skeletal maturation.

MAIN RESULTS

Among 22 eligible trials, 17 group comparisons were derived from 10 trials (3394 children with mild to moderate asthma), measured growth and contributed data to the meta-analysis. Trials used ICS (beclomethasone, budesonide, ciclesonide, fluticasone or mometasone) as monotherapy or as combination therapy with a long-acting beta2 -agonist and generally compared low (50 to 100 μg) versus low to medium (200 μg) doses of hydrofluoroalkane (HFA)-beclomethasone equivalent over 12 to 52 weeks. In the four comparisons reporting linear growth over 12 months, a significant group difference was observed, clearly indicating lower growth velocity in the higher ICS dose group of 5.74 cm/y compared with 5.94 cm/y on lower-dose ICS (N = 728 school-aged children; mean difference (MD)0.20 cm/y, 95% confidence interval (CI) 0.02 to 0.39; high-quality evidence): No statistically significant heterogeneity was noted between trials contributing data. The ICS molecules (ciclesonide, fluticasone, mometasone) used in these four comparisons did not significantly influence the magnitude of effect (X(2) = 2.19 (2 df), P value 0.33). Subgroup analyses on age, baseline severity of airway obstruction, ICS dose and concomitant use of non-steroidal antiasthmatic drugs were not performed because of similarity across trials or inadequate reporting. A statistically significant group difference was noted in unadjusted change in height from zero to three months (nine comparisons; N = 944 children; MD 0.15, 95% CI -0.28 to -0.02; moderate-quality evidence) in favour of a higher ICS dose. No statistically significant group differences in change in height were observed at other time points, nor were such differences in weight, bone mass index and skeletal maturation reported with low quality of evidence due to imprecision.

AUTHORS' CONCLUSIONS

In prepubescent school-aged children with mild to moderate persistent asthma, a small but statistically significant group difference in growth velocity was observed between low doses of ICS and low to medium doses of HFA-beclomethasone equivalent, favouring the use of low-dose ICS. No apparent difference in the magnitude of effect was associated with three molecules reporting one-year growth velocity, namely, mometasone, ciclesonide and fluticasone. In view of prevailing parents' and physicians' concerns about the growth suppressive effect of ICS, lack of or incomplete reporting of growth velocity in more than 86% (19/22) of eligible paediatric trials, including those using beclomethasone and budesonide, is a matter of concern. All future paediatric trials comparing different doses of ICS with or without placebo should systematically document growth. Findings support use of the minimal effective ICS dose in children with asthma.

PLAIN LANGUAGE SUMMARY

Does altering the dose of inhaled corticosteroids make a difference in growth among children with asthma?

BACKGROUND

Asthma guidelines recommend inhaled corticosteroids (ICS) as the first choice of treatment for children with persistent asthma that is not well controlled when only a reliever inhaler is used to treat symptoms. Steroids work by reducing inflammation in the lungs and are known to control underlying symptoms of asthma. However, parents and physicians remain concerned about the potential negative effect of ICS on growth.

REVIEW QUESTION

Does altering the dose of inhaled corticosteroids make a difference in the growth of children with asthma? WHAT EVIDENCE DID WE FIND?: We studied whether a difference could be seen in the growth of children with persistent asthma who were using different doses of the same ICS molecule and the same delivery device. We found 22 eligible trials, but only 10 of them measured growth or other measures of interest. Overall, 3394 children included in the review combined 17 group comparisons (i.e. 17 groups of children with mild to moderate asthma using a particular dose and type of steroid in 10 trials). Trials used different ICS molecules (beclomethasone, budesonide, ciclesonide, fluticasone or mometasone) either on their own or in combination with a long-acting beta2 -agonist (a drug used to open up the airways) and generally compared low doses of corticosteroids (50 to 100 μg) with low to medium (200 μg) doses of corticosteroids (converted in μg HFA-beclomethasone equivalent) over 12 to 52 weeks.

RESULTS

We found a small but statistically significant group difference in growth over 12 months between these different doses clearly favouring the lower dose of ICS. The type of corticosteroid among newer molecules (ciclesonide, fluticasone, mometasone) did not seem to influence the impact on growth over one year. Differences in corticosteroid doses did not seem to affect the change in height, the gain in weight, the gain in bone mass index and the maturation of bones. QUALITY OF THE EVIDENCE: This review is based on a small number of trials that reported data and were conducted on children with mild to moderate asthma. Only 10 of 22 studies measured the few outcomes of interest for this review, and only four comparisons reported growth over 12 months. Our confidence in the quality of evidence is high for this outcome, however it is low to moderate for several other outcomes, depending on the number of trials reporting these outcomes. Moreover, a few outcomes were reported only by a single trial; as these findings have not been confirmed by other trials, we downgraded the evidence for these outcomes to low quality. An insufficient number of trials have compared the effect of a larger difference in dose, for example, between a high dose and a low dose of ICS and of other popular molecules such as budesonide and beclomethasone over a year or longer of treatment.

CONCLUSIONS

We report an evidence-based ICS dose-dependent reduction in growth velocity in prepubescent school-aged children with mild to moderate persistent asthma. The choice of ICS molecule (mometasone, ciclesonide or fluticasone) was not found to affect the level of growth velocity response over a year. The effect of corticosteroids on growth was not consistently reported: among 22 eligible trials, only four comparisons reported the effects of corticosteroids on growth over one year. In view of parents' and clinicians' concerns, lack of or incomplete reporting of growth is a matter of concern given the importance of the topic. We recommend that growth be systematically reported in all trials involving children taking ICS for three months or longer. Until further data comparing low versus high ICS dose and trials of longer duration are available, we recommend that the minimal effective ICS dose be used in all children with asthma.

Inhaled corticosteroids in children with persistent asthma: effects on growth

BACKGROUND

Treatment guidelines for asthma recommend inhaled corticosteroids (ICS) as first-line therapy for children with persistent asthma. Although ICS treatment is generally considered safe in children, the potential systemic adverse effects related to regular use of these drugs have been and continue to be a matter of concern, especially the effects on linear growth.

OBJECTIVES

To assess the impact of ICS on the linear growth of children with persistent asthma and to explore potential effect modifiers such as characteristics of available treatments (molecule, dose, length of exposure, inhalation device) and of treated children (age, disease severity, compliance with treatment).

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR), which is derived from systematic searches of bibliographic databases including CENTRAL, MEDLINE, EMBASE, CINAHL, AMED and PsycINFO; we handsearched respiratory journals and meeting abstracts. We also conducted a search of ClinicalTrials.gov and manufacturers' clinical trial databases to look for potential relevant unpublished studies. The literature search was conducted in January 2014.

SELECTION CRITERIA

Parallel-group randomised controlled trials comparing daily use of ICS, delivered by any type of inhalation device for at least three months, versus placebo or non-steroidal drugs in children up to 18 years of age with persistent asthma.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction and assessment of risk of bias in included studies. We conducted meta-analyses using the Cochrane statistical package RevMan 5.2 and Stata version 11.0. We used the random-effects model for meta-analyses. We used mean differences (MDs) and 95% CIs as the metrics for treatment effects. A negative value for MD indicates that ICS have suppressive effects on linear growth compared with controls. We performed a priori planned subgroup analyses to explore potential effect modifiers, such as ICS molecule, daily dose, inhalation device and age of the treated child.

MAIN RESULTS

We included 25 trials involving 8471 (5128 ICS-treated and 3343 control) children with mild to moderate persistent asthma. Six molecules (beclomethasone dipropionate, budesonide, ciclesonide, flunisolide, fluticasone propionate and mometasone furoate) given at low or medium daily doses were used during a period of three months to four to six years. Most trials were blinded and over half of the trials had drop out rates of over 20%. Compared with placebo or non-steroidal drugs, ICS produced a statistically significant reduction in linear growth velocity (14 trials with 5717 participants, MD -0.48 cm/y, 95% CI -0.65 to -0.30, moderate quality evidence) and in the change from baseline in height (15 trials with 3275 participants; MD -0.61 cm/y, 95% CI -0.83 to -0.38, moderate quality evidence) during a one-year treatment period. Subgroup analysis showed a statistically significant group difference between six molecules in the mean reduction of linear growth velocity during one-year treatment (Chi(2) = 26.1, degrees of freedom (df) = 5, P value < 0.0001). The group difference persisted even when analysis was restricted to the trials using doses equivalent to 200 μg/d hydrofluoroalkane (HFA)-beclomethasone. Subgroup analyses did not show a statistically significant impact of daily dose (low vs medium), inhalation device or participant age on the magnitude of ICS-induced suppression of linear growth velocity during a one-year treatment period. However, head-to-head comparisons are needed to assess the effects of different drug molecules, dose, inhalation device or patient age. No statistically significant difference in linear growth velocity was found between participants treated with ICS and controls during the second year of treatment (five trials with 3174 participants; MD -0.19 cm/y, 95% CI -0.48 to 0.11, P value 0.22). Of two trials that reported linear growth velocity in the third year of treatment, one trial involving 667 participants showed similar growth velocity between the budesonide and placebo groups (5.34 cm/y vs 5.34 cm/y), and another trial involving 1974 participants showed lower growth velocity in the budesonide group compared with the placebo group (MD -0.33 cm/y, 95% CI -0.52 to -0.14, P value 0.0005). Among four trials reporting data on linear growth after treatment cessation, three did not describe statistically significant catch-up growth in the ICS group two to four months after treatment cessation. One trial showed accelerated linear growth velocity in the fluticasone group at 12 months after treatment cessation, but there remained a statistically significant difference of 0.7 cm in height between the fluticasone and placebo groups at the end of the three-year trial. One trial with follow-up into adulthood showed that participants of prepubertal age treated with budesonide 400 μg/d for a mean duration of 4.3 years had a mean reduction of 1.20 cm (95% CI -1.90 to -0.50) in adult height compared with those treated with placebo.

AUTHORS' CONCLUSIONS

Regular use of ICS at low or medium daily doses is associated with a mean reduction of 0.48 cm/y in linear growth velocity and a 0.61-cm change from baseline in height during a one-year treatment period in children with mild to moderate persistent asthma. The effect size of ICS on linear growth velocity appears to be associated more strongly with the ICS molecule than with the device or dose (low to medium dose range). ICS-induced growth suppression seems to be maximal during the first year of therapy and less pronounced in subsequent years of treatment. However, additional studies are needed to better characterise the molecule dependency of growth suppression, particularly with newer molecules (mometasone, ciclesonide), to specify the respective role of molecule, daily dose, inhalation device and patient age on the effect size of ICS, and to define the growth suppression effect of ICS treatment over a period of several years in children with persistent asthma.

PLAIN LANGUAGE SUMMARY

Do inhaled corticosteroids reduce growth in children with persistent asthma? Review question: We reviewed the evidence on whether inhaled corticosteroids (ICS) could affect growth in children with persistent asthma, that is, a more severe asthma that requires regular use of medications for control of symptoms.

BACKGROUND

Treatment guidelines for asthma recommend ICS as first-line therapy for children with persistent asthma. Although ICS treatment is generally considered safe in children, parents and physicians always remain concerned about the potential negative effect of ICS on growth. Search date: We searched trials published until January 2014. Study characteristics: We included in this review trials comparing daily use of corticosteroids, delivered by any type of inhalation device for at least three months, versus placebo or non-steroidal drugs in children up to 18 years of age with persistent asthma.

KEY RESULTS

Twenty-five trials involving 8471 children with mild to moderate persistent asthma (5128 treated with ICS and 3343 treated with placebo or non-steroidal drugs) were included in this review. Eighty percent of these trials were conducted in more than two different centres and were called multi-centre studies; five were international multi-centre studies conducted in high-income and low-income countries across Africa, Asia-Pacifica, Europe and the Americas. Sixty-eight percent were financially supported by pharmaceutical companies. Meta-analysis (a statistical technique that combines the results of several studies and provides a high level of evidence) suggests that children treated daily with ICS may grow approximately half a centimeter per year less than those not treated with these medications during the first year of treatment. The magnitude of ICS-related growth reduction may depend on the type of drug. Growth reduction seems to be maximal during the first year of therapy and less pronounced in subsequent years of treatment. Evidence provided by this review allows us to conclude that daily use of ICS can cause a small reduction in height in children up to 18 years of age with persistent asthma; this effect seems minor compared with the known benefit of these medications for asthma control.

QUALITY OF EVIDENCE

Eleven of 25 trials did not report how they guaranteed that participants had an equal chance of receiving ICS or placebo or non-steroidal drugs. All but six trials did not report how researchers were kept unaware of the treatment assignment list. However, this methodological limitation may not significantly affect the quality of evidence because the results remained almost unchanged when we excluded these trials from the analysis.

The bronchodilator response as a predictor of inhaled corticosteroid responsiveness in asthmatic children with normal baseline spirometry

RATIONALE

Although inhaled corticosteroids (ICS) are considered first line controller therapy in children with persistent asthma, heterogeneity of the ICS response can be an important clinical problem. The purpose of this study is to determine the value of the bronchodilator response (BDR) in identifying the ICS responder and establish the optimal BDR cut-point that could be particularly useful in the clinic setting when baseline spirometry is normal.

METHODS

Mexican American asthmatic children, 5-18 years, with normal baseline spirometry who required low dose (step 2), or medium dose (step 3) ICS therapy were evaluated by skin prick test for atopy, and pre- and post-bronchodilator spirometry. ICS responders were defined by a ≥7.5% improvement in the FEV1 following 4-6 weeks of therapy. The optimal cut-point was determined by Receiver Operator Characteristic (ROC) curves as the best balance between sensitivity and specificity.

RESULTS

There were 34.8% of the 132 study patients who were ICS responders. ROC curves showed the BDR ≥10% to be an optimal cut-point with sensitivity 46%, specificity 76%, positive predictive value (PPV) 50%, and negative predictive value (NPV) 72%. Atopic females with a BDR ≥10% had a PPV of 73%.

CONCLUSIONS

The composite phenotype of female gender, atopic, and the BDR of ≥10% identified 73% as ICS responders compared to 50% in our overall population with a BDR of ≥10% alone, with minimal false positives. We suggest that the BDR in conjunction with gender and atopic status be considered as potentially useful predictors of the ICS responder, particularly when baseline spirometry is normal.

Inhaled corticosteroids in children with persistent asthma: dose-response effects on growth

BACKGROUND

Inhaled corticosteroids (ICS) are the first-line treatment for children with persistent asthma. Their potential for growth suppression remains a matter of concern for parents and physicians.

OBJECTIVES

To assess whether increasing the dose of ICS is associated with slower linear growth, weight gain and skeletal maturation in children with asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov website up to March 2014.

SELECTION CRITERIA

Studies were eligible if they were parallel-group randomised trials evaluating the impact of different doses of the same ICS using the same device in both groups for a minimum of three months in children one to 17 years of age with persistent asthma.

DATA COLLECTION AND ANALYSIS

Two review authors ascertained methodological quality independently using the Cochrane Risk of bias tool. The primary outcome was linear growth velocity. Secondary outcomes included change over time in growth velocity, height, weight, body mass index and skeletal maturation.

MAIN RESULTS

Among 22 eligible trials, 17 group comparisons were derived from 10 trials (3394 children with mild to moderate asthma), measured growth and contributed data to the meta-analysis. Trials used ICS (beclomethasone, budesonide, ciclesonide, fluticasone or mometasone) as monotherapy or as combination therapy with a long-acting beta2-agonist and generally compared low (50 to 100 μg) versus low to medium (200 μg) doses of hydrofluoroalkane (HFA)-beclomethasone equivalent over 12 to 52 weeks. In the four comparisons reporting linear growth over 12 months, a significant group difference was observed, clearly indicating lower growth velocity in the higher ICS dose group of 5.74 cm/y compared with 5.94 cm/y on lower-dose ICS (N = 728 school-aged children; mean difference (MD)0.20 cm/y, 95% confidence interval (CI) 0.02 to 0.39; high-quality evidence): No statistically significant heterogeneity was noted between trials contributing data. The ICS molecules (ciclesonide, fluticasone, mometasone) used in these four comparisons did not significantly influence the magnitude of effect (X(2) = 2.19 (2 df), P value 0.33). Subgroup analyses on age, baseline severity of airway obstruction, ICS dose and concomitant use of non-steroidal antiasthmatic drugs were not performed because of similarity across trials or inadequate reporting. A statistically significant group difference was noted in unadjusted change in height from zero to three months (nine comparisons; N = 944 children; MD 0.15, 95% CI -0.28 to -0.02; moderate-quality evidence) in favour of a higher ICS dose. No statistically significant group differences in change in height were observed at other time points, nor were such differences in weight, bone mass index and skeletal maturation reported with low quality of evidence due to imprecision.

AUTHORS' CONCLUSIONS

In prepubescent school-aged children with mild to moderate persistent asthma, a small but statistically significant group difference in growth velocity was observed between low doses of ICS and low to medium doses of HFA-beclomethasone equivalent, favouring the use of low-dose ICS. No apparent difference in the magnitude of effect was associated with three molecules reporting one-year growth velocity, namely, mometasone, ciclesonide and fluticasone. In view of prevailing parents' and physicians' concerns about the growth suppressive effect of ICS, lack of or incomplete reporting of growth velocity in more than 86% (19/22) of eligible paediatric trials, including those using beclomethasone and budesonide, is a matter of concern. All future paediatric trials comparing different doses of ICS with or without placebo should systematically document growth. Findings support use of the minimal effective ICS dose in children with asthma.

Inhaled corticosteroids in children with persistent asthma: effects on growth

BACKGROUND

Treatment guidelines for asthma recommend inhaled corticosteroids (ICS) as first-line therapy for children with persistent asthma. Although ICS treatment is generally considered safe in children, the potential systemic adverse effects related to regular use of these drugs have been and continue to be a matter of concern, especially the effects on linear growth.

OBJECTIVES

To assess the impact of ICS on the linear growth of children with persistent asthma and to explore potential effect modifiers such as characteristics of available treatments (molecule, dose, length of exposure, inhalation device) and of treated children (age, disease severity, compliance with treatment).

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR), which is derived from systematic searches of bibliographic databases including CENTRAL, MEDLINE, EMBASE, CINAHL, AMED and PsycINFO; we handsearched respiratory journals and meeting abstracts. We also conducted a search of ClinicalTrials.gov and manufacturers' clinical trial databases to look for potential relevant unpublished studies. The literature search was conducted in January 2014.

SELECTION CRITERIA

Parallel-group randomised controlled trials comparing daily use of ICS, delivered by any type of inhalation device for at least three months, versus placebo or non-steroidal drugs in children up to 18 years of age with persistent asthma.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction and assessment of risk of bias in included studies. We conducted meta-analyses using the Cochrane statistical package RevMan 5.2 and Stata version 11.0. We used the random-effects model for meta-analyses. We used mean differences (MDs) and 95% CIs as the metrics for treatment effects. A negative value for MD indicates that ICS have suppressive effects on linear growth compared with controls. We performed a priori planned subgroup analyses to explore potential effect modifiers, such as ICS molecule, daily dose, inhalation device and age of the treated child.

MAIN RESULTS

We included 25 trials involving 8471 (5128 ICS-treated and 3343 control) children with mild to moderate persistent asthma. Six molecules (beclomethasone dipropionate, budesonide, ciclesonide, flunisolide, fluticasone propionate and mometasone furoate) [corrected] given at low or medium daily doses were used during a period of three months to four to six years. Most trials were blinded and over half of the trials had drop out rates of over 20%.Compared with placebo or non-steroidal drugs, ICS produced a statistically significant reduction in linear growth velocity (14 trials with 5717 participants, MD -0.48 cm/y, 95% CI -0.65 to -0.30, moderate quality evidence) and in the change from baseline in height (15 trials with 3275 participants; MD -0.61 cm/y, 95% CI -0.83 to -0.38, moderate quality evidence) during a one-year treatment period.Subgroup analysis showed a statistically significant group difference between six molecules in the mean reduction of linear growth velocity during one-year treatment (Chi² = 26.1, degrees of freedom (df) = 5, P value < 0.0001). The group difference persisted even when analysis was restricted to the trials using doses equivalent to 200 μg/d hydrofluoroalkane (HFA)-beclomethasone. Subgroup analyses did not show a statistically significant impact of daily dose (low vs medium), inhalation device or participant age on the magnitude of ICS-induced suppression of linear growth velocity during a one-year treatment period. However, head-to-head comparisons are needed to assess the effects of different drug molecules, dose, inhalation device or patient age. No statistically significant difference in linear growth velocity was found between participants treated with ICS and controls during the second year of treatment (five trials with 3174 participants; MD -0.19 cm/y, 95% CI -0.48 to 0.11, P value 0.22). Of two trials that reported linear growth velocity in the third year of treatment, one trial involving 667 participants showed similar growth velocity between the budesonide and placebo groups (5.34 cm/y vs 5.34 cm/y), and another trial involving 1974 participants showed lower growth velocity in the budesonide group compared with the placebo group (MD -0.33 cm/y, 95% CI -0.52 to -0.14, P value 0.0005). Among four trials reporting data on linear growth after treatment cessation, three did not describe statistically significant catch-up growth in the ICS group two to four months after treatment cessation. One trial showed accelerated linear growth velocity in the fluticasone group at 12 months after treatment cessation, but there remained a statistically significant difference of 0.7 cm in height between the fluticasone and placebo groups at the end of the three-year trial.One trial with follow-up into adulthood showed that participants of prepubertal age treated with budesonide 400 μg/d for a mean duration of 4.3 years had a mean reduction of 1.20 cm (95% CI -1.90 to -0.50) in adult height compared with those treated with placebo.

AUTHORS' CONCLUSIONS

Regular use of ICS at low or medium daily doses is associated with a mean reduction of 0.48 cm/y in linear growth velocity and a 0.61-cm change from baseline in height during a one-year treatment period in children with mild to moderate persistent asthma. The effect size of ICS on linear growth velocity appears to be associated more strongly with the ICS molecule than with the device or dose (low to medium dose range). ICS-induced growth suppression seems to be maximal during the first year of therapy and less pronounced in subsequent years of treatment. However, additional studies are needed to better characterise the molecule dependency of growth suppression, particularly with newer molecules (mometasone, ciclesonide), to specify the respective role of molecule, daily dose, inhalation device and patient age on the effect size of ICS, and to define the growth suppression effect of ICS treatment over a period of several years in children with persistent asthma.

The value of FeNO measurement in childhood asthma: uncertainties and perspectives

Asthma is considered an heterogeneous disease, requiring multiple biomarkers for diagnosis and management. Fractional exhaled nitric oxide in exhaled breath (FeNO) was the first useful non-invasive marker of airway inflammation in asthma and still is the most widely used. The non-invasive nature and the relatively easy use of FeNO technique make it an interesting tool to monitor airway inflammation and rationalize corticosteroid therapy in asthmatic patients, together with the traditional clinical tools (history, physical examination and lung function tests), even if some controversies have been published regarding the use of FeNO to support the management of asthma in children. The problem of multiple confounding factors and overlap between healthy and asthmatic populations preclude the routine application of FeNO reference values in clinical practice and suggest that it would be better to consider an individual "best", taking into account the context in which the measurement is obtained and the clinical history of the patient. Besides, there is still disagreement about the role of FeNO as a marker of asthma control, due to the complexity of balance among the different items involved in its determination and the lack of homogeneity in the population groups studied in the few studies conducted so far. Heterogeneity of problematic severe asthma greatly limits utility of FeNO alone as a biomarker of inflammation to optimize the disease management on an individual basis. None of the studies conducted so far demonstrated that the use of FeNO was better than current asthma guidelines in controlling asthma exacerbations. In summary, there is a large variation in FeNO levels between individuals, which may reflect the natural heterogeneity in baseline epithelial nitric oxide synthase activity and/or the contribution of other noneosinophilic factors to epithelial nitric oxide synthase activity. FeNO is a promising biomarker, but at present some limits are highlighted. We would recommend that further research can be carried out by organizing studies aimed to obtain reliable reference values of FeNO and in order to better interpret FeNO measurements in clinical settings, taking also into account the influence of genetic and environmental factors.

Leptin and urinary leukotriene E4 and 9α,11β-prostaglandin F2 release after exercise challenge

BACKGROUND

Leptin-related effects on inflammation and bronchial hyperresponsiveness (BHR) in the human airway have not been demonstrated.

OBJECTIVES

To investigate the relationship between the levels of serum leptin and BHR and urinary leukotriene E4 (LTE4) and 9α,11β-prostaglandin F2 (9α,11β-PGF(2)) release after exercise challenge in asthmatic children.

METHODS

Eighty-six prepubertal children between 6 and 10 years old were enrolled and divided into 4 groups: 19 obese asthmatic children, 25 normal-weight asthmatic children, 21 obese nonasthmatic children, and 21 healthy controls. We measured serum leptin levels and urinary LTE4 and 9α,11β-PGF2 levels in children before and 30 minutes after the exercise challenge.

RESULTS

Serum leptin levels were significantly higher in obese asthmatic children compared with normal-weight asthmatic children. Significant increases in urinary levels of LTE4 and 9α,11β-PGF2 were observed in obese asthmatic children after the exercise challenge. Although smaller than in obese asthmatic children, significant increases in the urinary levels of LTE4 and 9α,11β-PGF2 were also observed in the normal-weight. Asthmatic children Logarithmic serum leptin values were significantly associated with the logarithmic maximum percentage change in forced expiratory volume in 1 second, the logarithmic urinary LTE4 change, and the logarithmic urinary 9α,11β-PGF2 change from baseline to after exercise in both obese and normal-weight asthmatic children.

CONCLUSION

The serum levels of leptin were significantly associated with BHR and urinary LTE4 and 9α,11β-PGF2 release induced by exercise challenge in asthmatic children.

Assessment of airflow limitation, airway inflammation, and symptoms during virus-induced wheezing episodes in 4- to 6-year-old children

Background

It is disputed whether recurrent episodes of wheeze in preschool-aged children comprise a distinct asthma phenotype.

Objective

We sought to prospectively assess airflow limitation and airway inflammation in children 4 to 6 years old with episodic virus-induced wheeze.

Methods

Ninety-three children 4 to 6 years old with a history of mild, virus-induced episodes of wheeze who were able to perform acceptable fraction of exhaled nitric oxide (Feno) maneuvers and spirometry (with forced expiratory time ≥0.5 seconds) were followed prospectively. Lung function and Feno values were measured every 6 weeks (baseline) within the first 48 hours of an acute wheezing episode (day 0) and 10 and 30 days later. Symptom scores and peak flow measurement were recorded daily.

Results

Forty-three children experienced a wheezing episode. At day 0, Feno values were significantly increased, whereas forced expiratory volume at 0.5 seconds (FEV_0.5) significantly decreased compared with baseline (16 ppb [interquartile range {IQR}, 13-20 ppb] vs 9 ppb IQR, 7-11 ppb] and 0.84 L [IQR, 0.75-0.99 L] vs 0.99 L [IQR, 0.9-1.07 L], respectively; both P < .001). Airflow limitation at day 0 was reversible after bronchodilation. FEV_0.5 and Feno values were significantly associated with each other and with lower and upper respiratory tract symptoms when assessed longitudinally but not cross-sectionally at all time points independently of atopy. Feno and FEV_0.5 values returned to baseline levels within 10 days.

Conclusions

Mild episodes of wheeze in preschoolers are characterized by enhanced airway inflammation, reversible airflow limitation, and asthma-related symptoms. Feno values increase significantly during the first 48 hours and return to personal baseline within 10 days from the initiation of the episode. Longitudinal follow-up suggests that symptoms, inflammation, and lung function correlate well in this phenotype of asthma.

High exhaled nitric oxide levels may predict bronchial reversibility in allergic children with asthma or rhinitis

BACKGROUND

Allergic asthma and rhinitis may be associated. Airway inflammation is shared by both disorders. The measure of the fractional concentration of exhaled nitric oxide (FeNO) may be considered as a surrogate marker for airway inflammation, mainly in allergic patients. Reversibility to bronchodilation (BD) testing is a functional characteristic of asthma.

OBJECTIVE

The aim of this study was to evaluate whether FeNO may predict reversibility to BD in a pediatric cohort of allergic subjects with asthma (180) or rhinitis (150).

METHODS

Lung function (including forced expiratory volume at the first second (FEV(1)), forced volume capacity (FVC), forced expiratory flow at 25-75% of volume capacity (FEF (25-75))), FeNO measurement, and BD testing were performed in all children.

RESULTS

Lung function, FeNO, and sensitization type were significantly different in the two groups. A strong correlation was found between FeNO and ΔFEV(1) after BD. Two main predictors of reversibility were FeNO values >34 ppb [Odds RatioAdj (ORAdj) = 1.9] and sensitization to perennial allergens (ORAdj = 1.7).

CONCLUSIONS

This study provided evidence that FeNO was strongly related with the response to BD testing and could predict bronchial reversibility in children with allergic rhinitis or asthma. Therefore, a simple FeNO measurement could suggest relevant information about bronchial reversibility.

Bronchodilator responses after methacholine and adenosine 5'-monophosphate (AMP) challenges in children with asthma: their relationships with eosinophil markers

BACKGROUND

Bronchodilator responsiveness (BDR) and eosinophilic inflammation are characteristic features of asthma. Objective. The aim of this study was to compare the relationships of BDR after methacholine challenge or adenosine 5'-monophosphate (AMP) challenge to blood eosinophil markers in children with asthma.

METHODS

Methacholine and AMP challenges were performed on 69 children with mild intermittent to moderate persistent asthma. BDR was calculated as the change in forced expiratory volume in 1 second, expressed as percentage change of the value immediately after the each challenge and the value after inhalation of salbutamol. Serum total IgE levels, blood eosinophil counts, and serum eosinophil cationic protein (ECP) levels were determined for each subject.

RESULTS

A positive relationship between serum total IgE levels and BDR was found only after the AMP challenge (R(2) = 0.345, p = .001) rather than after the methacholine challenge (R(2) = 0.007, p = .495). Peripheral blood eosinophil counts correlated more significantly with BDR after AMP challenge (R(2) = 0.212, p = .001) than BDR after methacholine challenge (R(2) = 0.002, p = .724). Both BDR after methacholine challenge (R(2) = 0.063, p = .038) and BDR after AMP challenge (R(2) = 0.192, p = .001) were significantly correlated with serum ECP levels.

CONCLUSION

BDR after AMP challenge may be more closely related to eosinophilic inflammation, compared with that after methacholine challenge.

The relationship of the bronchodilator response phenotype to poor asthma control in children with normal spirometry

OBJECTIVE

To determine the relationship of poor asthma control to bronchodilator response (BDR) phenotypes in children with normal spirometry.

STUDY DESIGN

Children with asthma were assessed for clinical indexes of poorly controlled asthma. Pre- and post-bronchodilator spirometry were performed, and the percent BDR was determined. Multivariate logistic regression assessed the relationship of the clinical indices to BDR at ≥ 8%, ≥ 10%, and ≥ 12% BDR thresholds.

RESULTS

There were 510 controller naïve children and 169 on controller medication. In the controller naïve population the mean age (± 1 SD) was 9.5 (3.4); 57.1% were male, 85.7% Hispanic. Demographics were similar in both populations. In the adjusted profile, significant clinical relationships were found particularly to positive BDR phenotypes ≥ 10% and ≥ 12% versus negative responses including younger age, (OR 2.0, 2.5; P < .05), atopy (OR 1.9, 2.6; P < .01), nocturnal symptoms in females (OR 3.4, 3.8; P < .01); β₂ agonist use (OR 1.7, 2.8; P < .01); and exercise limitation (OR 2.2, 2.5; P < .01) only in the controller naïve population.

CONCLUSIONS

The BDR phenotype ≥ 10% is significantly related to poor asthma control, providing a potentially useful objective tool in controller naïve children even when the pre-bronchodilator spirometry result is normal.

Human exhaled breath analysis

OBJECTIVE

To review the fast-developing topic of assessment of exhaled breath components to improve the diagnosis and monitoring of respiratory and systemic diseases.

DATA SOURCES

Review of the literature available in monographs and journals.

STUDY SELECTION

Articles and overviews on the broad spectrum of existing experimental and routinely applied methods to assess different aspects of human exhaled breath analysis were selected for presentation in this review.

RESULTS

Exhaled breath constitutes more than 3,500 components, the bulk of which are volatile organic compounds in miniature quantities. Many of these characterize the functioning of the organism as a whole (systemic biomarkers), but some are related to processes taking place in the respiratory system and the airways in particular (lung biomarkers). Assessment of lung biomarkers has proven useful in airway inflammatory diseases. It involves direct measurement of gases such as nitric oxide and inflammatory indicators in exhaled breath condensate such as oxidative stress markers (eg, hydrogen peroxide and isoprostanes), nitric oxide derivatives (eg, nitrate and nitrates), arachidonic acid metabolites (eg, prostanoids, leukotrienes, and epoxides), adenosine, and cytokines. Integral approaches have also been suggested, such as exhaled breath temperature measurement and devices of the "electronic nose" type, which enable the capture of approaches have also been suggested, such as exhaled breath temperature measurementexhaled molecular fingerprints (breath prints). Technical factors related to standardization of the different techniques need to be resolved to reach the stage of routine applicability.

CONCLUSIONS

Examination of exhaled breath has the potential to change the existing routine approaches in human medicine. The rapidly developing new analytical and computer technologies along with novel, unorthodox ideas are prerequisites for future advances in this field.

Allergen exposure modifies the relation of sensitization to fraction of exhaled nitric oxide levels in children at risk for allergy and asthma

BACKGROUND

Studies on airway inflammation, measured as fraction of exhaled nitric oxide (FENO), have focused on its relation to control of asthma, but the contribution of allergen exposure to the increase in FENO levels is unknown.

OBJECTIVE

We evaluated (1) whether FENO levels were increased in children with allergic sensitization or asthma; (2) whether specific allergen exposure increased FENO levels in sensitized, but not unsensitized, children; and (3) whether sedentary behavior increased FENO levels independent of allergen exposures.

METHODS

At age 12 years, in a birth cohort of children with a parental history of allergy or asthma, we measured bed dust allergen (dust mite, cat, and cockroach) by means of ELISA, specific allergic sensitization primarily based on specific IgE levels, and respiratory disease (current asthma, rhinitis, and wheeze) and hours of television viewing/video game playing by means of questionnaire. Children performed spirometric maneuvers before and after bronchodilator responses and had FENO levels measured by using electrochemical detection methods (NIOX MINO).

RESULTS

FENO levels were increased in children with current asthma (32.2 ppb), wheeze (27.0 ppb), or rhinitis (23.2 ppb) compared with subjects without these respective symptoms/diagnoses (16.4-16.6 ppb, P < .005 for all comparisons). Allergic sensitization to indoor allergens (cat, dog, and dust mite) predicted higher FENO levels and explained one third of the variability in FENO levels. FENO levels were highest in children both sensitized and exposed to dust mite. Greater than 10 hours of weekday television viewing was associated with a 0.64-log increase in FENO levels after controlling for indoor allergen exposure, body mass index, and allergic sensitization.

CONCLUSION

Allergen exposures and sedentary behavior (television viewing/video game playing) might increase airway inflammation, which was measured as the FENO.

Associations of Fraction of Exhaled Nitric Oxide with Beta Agonist Use in Children with Asthma

The fraction of exhaled nitric oxide (FeNO), a measure of airway inflammation, is a potential noninvasive tool to guide asthma management in children. It remains unclear, however, if FeNO adds any information beyond clinical assessment of asthma control. We evaluated the associations of FeNO level with short acting beta agonist use and compared it with other clinical asthma assessments. We examined a prospective cohort study of 225 tobacco-smoke-exposed children aged 6-12 years with doctor-diagnosed asthma, including measures of FeNO, reported days of short acting beta agonist use, and unscheduled asthma visits. FeNO was analyzed in relation to current and future (3 months later) short acting beta agonist use. Mean FeNO at baseline, 6, and 12 months was 15.5, 15.7, and 16.8 ppb. In multivariable analyses, higher FeNO level was associated with increased short acting beta agonist use but only among children who were not on inhaled corticosteroids. Among those not on an inhaled steroid, there was a 12% increase in current and 15% increase in future days of short acting beta agonist use for every 10 ppb increase in FeNO level. FeNO levels remained associated with current short acting beta agonist use even after adjusting for unscheduled asthma visits. FeNO levels remained associated with future short acting beta agonist use even after adjusting for current short acting beta agonist use or unscheduled asthma visits. We conclude that FeNO levels are associated with short acting beta agonist use but only among children who are not on an inhaled corticosteroid.

Measurement of exhaled nitric oxide: comparison of different analysers

BACKGROUND AND OBJECTIVE

Exhaled nitric oxide (NO) is used as a surrogate marker to monitor eosinophilic airway inflammation, assist in diagnosis, and support treatment decisions for asthma patients. The aim of this study was to compare five NO analysers: Medisoft (M), Aerocrine Niox (N), Aerocrine Niox flex (NF), Aerocrino Niox mino (NM) and EcoMedics (E).

METHODS

In 85 subjects (25 asthma patients, 25 COPD patients, 35 healthy volunteers; median age 36.5 years, range 23-79, 47% female), three NO measurements per individual were performed, using each analyser according to the American Thoracic Society/European Respiratory Society guidelines. Subjects evaluated the devices on the basis of comfort and ease of performing the measurement.

RESULTS

Median NO concentrations were 24.8 parts per billion (ppb) (range 6.3-262.7) for M, 14.5 ppb (0.0-196.6) for N, 15.2 ppb (5.6-67.7) for NF, 16.3 ppb (5.0-208.3) for NM, and 13.1 ppb (4.0-103.0) for E. There was significant correlation among the absolute NO values measured with all the devices (0.743 for M vs NF < r < 0.979 for N vs NF). Bland-Altman plots suggested an acceptable degree of agreement among the results obtained with the three Niox analysers. Measurements obtained with the Medisoft and Ecomedics analysers were not directly comparable with those obtained with the other devices. The greatest differences in absolute NO levels for individual patients were between measurements with the M and E analysers (8.3 ppb, range 27.4-159.7, P < 0.001). Acceptance of the measurements by patients was high, independent of the device used.

CONCLUSIONS

Exhaled NO values obtained with different devices were not directly comparable and may differ to a clinically relevant extent, depending on which device is used.

Exhaled NO among inner-city children in New York City

BACKGROUND

Fractional exhaled nitric oxide (FeNO) has been proposed as a biomarker of airway inflammation for cohort studies of asthma.

OBJECTIVES

To assess the association between FeNO and asthma symptoms among 7-year-old children living in an inner-city community. To test the association between environmental tobacco smoke (ETS) exposure (previous and current) and FeNO among these children.

METHODS

As part of a longitudinal study of asthma, children recruited in Head Start centers at age 4 had offline FeNO and lung function testing at age 7. Children with allergen-specific immunoglobulin E (IgE) (≥0.35 IU/mL) at age 7 were considered seroatopic. ETS exposure at ages 4 and 7 was assessed by questionnaire.

RESULTS

Of 144 participating children, 89 had complete questionnaire data and achieved valid FeNO and lung function tests. Children with reported wheeze in the previous 12 months (n = 19) had higher FeNO than those without wheeze (n = 70) (geometric means 17.0 vs. 11.0 ppb, p = .005). FeNO remained significantly associated with wheeze (p = .031), after adjusting for seroatopy and forced expiratory volume in 1 second (FEV₁) in multivariable regression. FeNO at age 7 was positively associated with domestic ETS exposure at age 4 (29%) (β = 0.36, p = .015) but inversely associated with ETS exposure at age 7 (16%) (β = -0.74, p < .001).

CONCLUSIONS

Given its association with current wheeze, independent of seroatopy and lung function, FeNO provides a relevant outcome measure for studies in inner-city communities. While compelling, the positive association between ETS exposure at age 4 and a marker of airway inflammation at age 7 should be confirmed in a larger study.

The role of inhaled and/or nasal corticosteroids on the bronchodilator response

PURPOSE

To compare the profiles of the bronchodilator response (BDR) among children with asthma and/or allergic rhinitis (AR) and to determine whether BDR in these children is reduced by treatment with inhaled and/or nasal corticosteroid.

METHODS

Sixty-eight children with asthma (mean age, 10.9 years), 45 children with comorbid asthma and AR (mean age, 10.5 years), and 44 children with AR alone (mean age, 10.2 years) were investigated. After a 2-week baseline period, all children were treated with inhaled fluticasone propionate (either 100 or 250 µg b.i.d., tailored to asthma severity) or nasal fluticasone propionate (one spray b.i.d. in each nostril) or both, according to the condition. Before and 2 weeks after starting treatment, all children were evaluated with spirometry and bronchodilator testing. BDR was calculated as a percent change from the forced expiratory volume in 1 second (FEV(1)) at baseline.

RESULTS

The mean BDR was 10.3% [95% confidence interval (CI) 8.3-12.4%] in children with asthma, 9.0% (95% CI 7.3-10.9%) in subjects with asthma and AR, and 5.0% (95% CI 4.1-5.9%) in children with AR alone (P<0.001). After treatment, the mean BDR was reduced to 5.2% (95% CI 4.2-6.3%) (P<0.001) in children with asthma and to 4.5% (95% CI 3.5-5.5%) (P<0.001) in children with asthma and AR. However, children with rhinitis showed no significant change in BDR after treatment, with the mean value being 4.7% (95% CI 3.7-5.8%) (P=0.597).

CONCLUSION

The findings of this study imply that an elevated BDR in children with AR cannot be attributed to nasal inflammation alone and highlights the close relationship between the upper and lower airways.

Lung function in preschool children with a history of wheezing measured by forced oscillation and plethysmographic specific airway resistance

RATIONALE

Wheezing is common in preschool children, but objective evidence for airway obstruction and its reversibility are rarely available in clinical practice. We assessed whether abnormalities of lung function and bronchodilator response can be detected in preschool children using the forced oscillation technique and measurements of specific airway resistance.

METHODS

Fifty-nine children with a history of wheeze and 24 healthy controls aged 3-6 years were recruited. Resistance and reactance at 6 and 8 Hz (Rrs6, Rrs8, Xrs6 and Xrs8, respectively) were measured using the forced oscillation technique and specific airway resistance was measured in a plethysmograph. z-Scores were calculated from published reference data. Tests were repeated 15 min after 400 mcg salbutamol. Bronchodilator response was expressed as the log-transformed ratio of postbronchodilator/prebronchodilator values.

RESULTS

Technically acceptable measurements using the forced oscillation technique were obtained in n = 77 (93%) of children and in n = 56 (68%) using plethysmography. There was no significant difference in baseline lung function or bronchodilator response, assessed by either technique, between those with a history of wheeze and healthy controls.

CONCLUSION

Measurement of lung function is feasible in preschool children, but neither of these techniques was able to identify diminished lung function or reversibility to bronchodilator in children with a history of wheeze.

Urinary leukotriene E4/exhaled nitric oxide ratio and montelukast response in childhood asthma

BACKGROUND

A subset of children with asthma respond better to leukotriene receptor antagonists than to inhaled corticosteroids. Information is needed to identify children with these preferential responses.

OBJECTIVE

We sought to determine whether the ratio of urinary leukotriene E(4) (LTE(4)) to fractional exhaled nitric oxide (FE(NO)) delineates children with preferential responsiveness to montelukast compared with fluticasone propionate (FP) therapy.

METHODS

Data from 318 children with mild-to-moderate asthma enrolled in 2 National Heart, Lung, and Blood Institute Childhood Asthma Research and Education Network studies (Characterizing the Response to a Leukotriene Receptor Antagonist and an Inhaled Corticosteroid [CLIC] and the Pediatric Asthma Controller Trial [PACT]) were analyzed. The association between LTE(4)/FE(NO) ratios at baseline and improved lung function or asthma control days (ACDs) with montelukast and FP therapy was determined, and phenotypic characteristics related to high ratios were assessed.

RESULTS

LTE(4)/FE(NO) ratios were associated with a greater response to montelukast than FP therapy for FEV(1) measurements (2.1% increase per doubling of ratio, P = .001) and for ACDs per week (0.3-ACD increase, P = .009) in the CLIC study. In PACT the ratio was associated with greater ACD responsiveness to MT than FP therapy (0.6 ACD increase, P=.03) [corrected]. In a combined study analysis, LTE(4): FE(NO) ratios were associated with greater response to MT than FP therapy for FEV(1) (1.8% increase, P =.0005) and ACDs (0.4 increase, P =.001)[corrected].Children with LTE(4)/FE(NO) ratios at or above the 75th percentile were likely (P < .05) to be younger and female and exhibit lower levels of atopic markers and methacholine reactivity.

CONCLUSION

LTE(4)/FE(NO) ratios predict a better response to montelukast than FP therapy in children with mild-to-moderate asthma.

Lung function measurement in the assessment of childhood asthma: recent important developments

PURPOSE OF REVIEW

To present three clinically important developments related to the utilization of pulmonary function to objectively assess the asthmatic child.

RECENT FINDINGS

The new asthma guidelines (2007) have added the forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio to the FEV1 as spirometric criteria for classifying asthma. Although a better indicator of airway obstruction, it has not clearly been shown to correlate with clinical criteria. The normal cut point for the ratio used in the guidelines of 85% for children may be too high, and compared to the lower limits of normal of 80%, could result in unnecessary treatment in some children. The bronchodilator response (BDR) phenotype reflects airway lability and has been associated with biomarkers of inflammation and responsiveness to inhaled corticosteroids as well as predicting long-term outcomes. Several studies have shown improved spirometric techniques in preschoolers as well as defining normal values in this age group. Impulse oscillometry (IOS), which is less demanding than spirometry, has been shown to identify asthmatic preschoolers in some cases better than spirometry and possibly identifying obstruction in the peripheral airways. It may also be a more useful test than spirometry in evaluating long-term drug studies.

SUMMARY

In addition to the FEV1/FVC ratio to detect airway obstruction, the BDR phenotype would appear to give important additional information regarding airway lability and inflammation, and should be included as routine spirometry. IOS is a promising test to identify asthmatic preschoolers, but more studies are needed to determine exactly what it measures and what constitutes normal values.

Recent advances in pediatric asthma treatment

Although wheezing illness is at its most prevalent in infancy and early childhood, its self-limiting nature in the majority poses considerable challenges in offering a long-term prognosis and in initiating long-term prophylaxis. Many of the established treatments in adults have not been adequately assessed in children. Evidence is also emerging for a number of different wheezing syndromes, several of which do not to respond well to currently available medicines. Much research interest is being directed to underlying changes within the airway that appear to be independent of allergic mechanisms and that may lead to novel therapeutic approaches. The aim of this review is to restate and update current best-practice based on evidence, to encourage effective and safe use of asthma medication in children and to point to areas of ongoing research that are likely to influence management decisions in the near future.

Exhaled nitric oxide, lung function, and exacerbations in wheezy infants and toddlers

BACKGROUND

There are limited data assessing the relationship between fraction of exhaled nitric oxide and lung function or exacerbations in infants with recurrent wheezing.

OBJECTIVES

In a longitudinal pilot study of children less than 2 years old, we assessed whether baseline fraction of exhaled nitric oxide was associated with lung function, bronchodilator responsiveness, changes in lung function, or subsequent exacerbations of wheezing.

METHODS

Forced expiratory flows and volumes using the raised-volume rapid thoracic compression method were measured in 44 infants and toddlers (mean age, 15.7 months) with recurrent wheezing. Single-breath exhaled nitric oxide (SB-eNO) was measured at 50 mL/s. Lung function was again measured 6 months after enrollment.

RESULTS

At enrollment, forced expiratory volume in 0.5 seconds (FEV(0.5)), forced expiratory flow at 25% to 75% of expiration (FEF(25-75)), and forced expiratory flow at 75% of expiration (FEF(75)) z scores for the cohort were significantly less than zero. There was no correlation between enrollment SB-eNO levels and enrollment lung function measures. SB-eNO levels were higher in infants with bronchodilator responsiveness (46.1 vs 23.6 ppb, P < .001) and was associated with a decrease in FEV(0.5) (r = -0.54, P = .001), FEF(25-75) (r = -0.6, P < .001), and FEF(75) (r = -0.55, P = .001) over 6 months. A 10-ppb increase in SB-eNO level was associated with a 0.4-point z score decrease in FEV(0.5), a 0.4-point z score decrease in FEF(25-75), and a 0.42-point z score decrease in FEF(75). SB-eNO level was superior to lung function and bronchodilator responsiveness in predicting subsequent wheezing treated with systemic steroids.

CONCLUSIONS

SB-eNO level might predict changes in lung function and risk of future wheezing and holds promise as a biomarker to predict asthma in wheezy infants and toddlers.

Association among lung function, exhaled nitric oxide, and the CAN questionnaire to assess asthma control in children

BACKGROUND

The aim of this study was to investigate the association among a validated symptom-based questionnaire for asthma control in children (CAN), forced expiratory volume in 1 sec (FEV(1)), and fractional exhaled nitric oxide (FE(NO)).

METHODS

Observational cross-sectional study was performed in a consecutive sample of asthmatic children aged between 7 and 14 years old from December 2007 to February 2008. FE(NO) was measured with a portable electrochemical analyzer and forced spirometry was performed according to American Thoracic Society/European Respiratory Society. The CAN questionnaire was completed by the parents (aged <9 years old) or by the children (> or = 9 years old). The strength of the association among FEV(1), FE(NO), and CAN questionnaire was studied using Spearman's rho, and the degree of agreement for asthma control among FEV(1), FE(NO), and CAN questionnaire, with classification of these variables according to values of normality, was studied using Pearson's chi(2) test and Cohen's kappa (KC).

RESULTS

We studied 268 children, mean age 9.7 +/- 2.1 years. Significant correlations were found between FE(NO) and CAN (r = 0.2), between FEV(1) and CAN (r = -0.3), and between FE(NO) and FEV(1) (r = -0.12). On classifying the variables according to values of normality, no agreement was found to establish the degree of asthma control between FE(NO) and CAN (KC = 0.18, chi(2) Pearson = 9.63); between FEV(1) and CAN (KC = 0.29, chi(2) = 38.5); or between FE(NO) and FEV(1) (KC = 0.07, chi(2) = 4.9).

CONCLUSIONS

The association among the three measurement instruments used to assess asthma control (FEV(1), FE(NO), and CAN) was weak. These are instruments that quantify variables that influence asthma in different ways, in this sense, none can be used instead of another in asthma management although they are complementary.

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.