Adolescents in clinical remission of atopic asthma have elevated exhaled nitric oxide levels and bronchial hyperresponsiveness

SANI clinical remission definition: a useful tool in severe asthma management

In the field of severe asthma, the concept of disease control has recently been integrated by the one of clinical remission. With this new concept, we move on to analyze the efficacy of therapy on multiple parameters simultaneously, starting with the mandatory discontinuation of the systemic glucocorticoids, to which is added the effect on exacerbations, respiratory function, and symptoms control. The Italian severe asthma registry SANI (Severe Asthma Network Italy) drafted criteria for the definition of disease remission, allowing patients to be classified into two groups, partial and complete remission. The greater dynamism of the definition, provided by SANI, allows us to hypothesize its practical use, concerning therapy management of severe asthma patients, starting from the level of remission, with the aim to facilitate the clinical decision on replacement, continuation or modulation of patients' therapy.

Current Challenges in Pediatric Asthma

Asthma is a chronic lung disease characterized by reversible bronchoconstriction and inflammation of the bronchi. Its increasing prevalence in childhood as well as different triggers make asthma a challenging disease in several ways: defining its phenotype/endotype, the diagnostic approach (especially in younger children), therapeutic options, and systematic follow-up. Considering these problems, this review approaches the current status and limitations of guidelines used for asthma management in children. It also emphasizes the key points which could lead to a better understanding and the direction to take in future studies.

Airway Hyperresponsiveness, but Not Bronchoalveolar Inflammatory Cytokines Profiles, Is Modified at the Subclinical Onset of Severe Equine Asthma

Airway hyperresponsiveness (AHR) and inflammation are both observed in human and equine asthma. The aim of this study was to assess the timeline and relationship of both features at the subclinical onset of severe equine asthma (SEA). First, the repeatability of the pulmonary function test (PFT) using impulse oscillometry system, and the methacholine bronchoprovocation test (BPT) were assessed at a 1-day interval on six SEA horses in clinical remission and six control horses. Then, clinical and ancillary tests were performed before and after a 1-week low-dust environmental challenge, including weighted clinical score, respiratory endoscopy, bronchoalveolar fluid cytology, PFT, and BPT. Both PFT and BPT showed acceptable repeatability. No test allowed SEA horses in clinical remission to be distinguished from control, unlike in human patients. Because of the low-dust environment, no significant difference was observed in the results of clinical and conventional ancillary examinations after the challenge. However, SEA horses showed increased AHR after the environmental challenge. At that stage, no signs of inflammation or changes in pro-inflammatory cytokines profiles (quantification and gene expression) were observed, suggesting AHR is present at an earlier stage of equine asthma than airway inflammation. This feature indicates SEA could present in a different disease pathway than neutrophilic human asthma.

Biomarkers of asthma relapse and lung function decline in adults with spontaneous asthma remission: A population-based cohort study

BACKGROUND

The extent to which biomarkers of asthma activity persist in spontaneous asthma remission and whether such markers are associated with future respiratory outcomes remained unclear. We investigated the association between sub-clinical inflammation in adults with spontaneous asthma remission and future asthma relapse and lung function decline.

METHODS

The Tasmanian Longitudinal Health Study is a population-based cohort (n = 8583). Biomarkers of systemic inflammation were measured on participants at age 45, and latent profile analysis was used to identify cytokine profiles. Bronchial hyperresponsiveness (BHR) and nitric oxide products in exhaled breath condensate (EBC NOx) were measured at age 50. Participants with spontaneous asthma remission at ages 45 (n = 466) and 50 (n = 318) were re-evaluated at age 53, and associations between baseline inflammatory biomarkers and subsequent asthma relapse and lung function decline were assessed.

RESULTS

We identified three cytokine profiles in adults with spontaneous asthma remission: average (34%), Th2-high (42%) and Th2-low (24%). Compared to the average profile, a Th2-high profile was associated with accelerated decline in post-BD FEV1 /FVC (MD -0.18% predicted per-year; 95% CI -0.33, -0.02), while a Th2-low profile was associated with accelerated decline in both post-BD FEV1 (-0.41%; -0.75, -0.06) and post-BD FVC (-0.31%; -0.62, 0.01). BHR and high TNF-α during spontaneous remission were associated with an increased risk of asthma relapse. In contrast, we found no evidence of association between EBC NOx and either asthma relapse or lung function decline.

CONCLUSION

BHR and serum inflammatory cytokines have prognostic value in adults with spontaneous asthma remission. At-risk individuals with BHR, Th2-high or Th2-low cytokine profiles may benefit from closer monitoring and on-going follow-up.

Evaluation of barometric whole-body plethysmography for therapy monitoring in cats with feline lower airway disease

OBJECTIVES

Feline lower airway disease (FLAD) is a common respiratory condition in cats. Traditionally, response to therapy is monitored only by evaluation of clinical signs and radiographic examination of the lungs. Barometric whole-body plethysmography (BWBP) is considered a non-invasive, well-tolerated form of measuring airway reactivity in cats. The aim of the study was to assess pulmonary function testing by BWBP for non-invasive evaluation of response to therapy in cats with FLAD and to investigate whether BWBP parameters correlate with clinical severity.

MATERIAL AND METHODS

The prospective study included 25 client-owned cats, diagnosed with FLAD on the basis of their medical history, clinical signs, radiographic findings, and bronchoalveolar lavage fluid (BALF) examination. At three time points (day 0, 14, and 60), a standardised owner questionnaire, a clinical examination and BWBP measurements were carried out. Results of the questionnaire and the clinical examination were evaluated using a clinical 12-point score. Individual therapy was administered to all patients after diagnosis, based on the severity of disease and compliance of the cat.

RESULTS

The total clinical score significantly improved over the entire study period (p<0.001). Significant improvement was detected for the frequency of coughing (p = 0.009), respiratory distress (p = 0.001), lung auscultation findings (p = 0.002), and general condition and appetite (p = 0.045). The BWBP parameter Penh, an indicator of bronchoconstriction, improved significantly under initial therapy between day 0 and 14 (p = 0.009). A significant correlation between Penh and the severity of auscultation findings was seen on day 0 (r = 0.40; p = 0.013).

CONCLUSION

The study supports the role of Penh as a non-invasive parameter for monitoring initial treatment response in cats with FLAD. Further studies are needed to address whether other BWBP parameters might be suitable for non-invasive therapy monitoring of FLAD. Clinical evaluation is always essential in cats with FLAD to evaluate treatment response.

Issues affecting young people with asthma through the transition period to adult care

Asthma is among the most common medical conditions affecting children and young people, with adolescence a recognised period of increased risk, overrepresented in analyses examining recent increasing asthma mortality rates. Asthma may change significantly during this period and management also occurs in the context of patients seeking increased autonomy and self-governance whilst navigating increasing academic and social demands. A number of disease factors can destabilise asthma during adolescence including: increased rates of anaphylaxis, anxiety, depression, obesity, and, in females, an emerging resistance to corticosteroids and the pro-inflammatory effects of oestrogen. Patient factors such as smoking, vaping, poor symptom recognition, treatment non-adherence and variable engagement with health services contribute to difficult to treat asthma. Significant deficiencies in the current approach to transition have been identified by a recent EAACI task force, and subsequent asthma-specific recommendations, published in 2020 provide an important framework moving forward. As with other chronic conditions, effective transition programmes plan ahead, engage with adolescents and their families to identify the patients' management priorities and the current challenges they are experiencing with treatment. Transition needs may vary significantly across asthma patients and for more complex asthma may include dedicated transition clinics involving multidisciplinary care requiring input including, amongst others, allergy and immunology, psychological medicine, respiratory physicians and scientists and nurse specialists. Across different global regions, barriers to treatment may vary but need to be elicited and an individualised approach taken to optimising asthma care which is sustainable within the local adult healthcare system.

Accelerated decline in lung function in adults with a history of remitted childhood asthma

AIM

A significant number of children with asthma show remission in adulthood. Although these adults are often diagnosed with chronic obstructive pulmonary disease in later life, the effect of clinically remitted childhood asthma on the decline in lung function during adulthood is uncertain. We examined whether clinical remission of childhood asthma was associated with an accelerated decline in lung function in apparently non-asthmatic adults.

METHODS

Here, 3584 participants (mean age, 48.1 years; range, 35-65 years) who did not have adulthood asthma and other lung diseases and had normal lung function at the baseline visit were included. They were categorised as follows: those with remitted childhood asthma (n=121) and healthy controls (n=3463) according to their self-reported childhood asthma history. Spirometry was performed at baseline and follow-up visits.

RESULTS

The mean follow-up time was 5.3 years. Multivariate regression analysis showed that remitted childhood asthma and smoking were independently associated with a rapid decline in forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC). Besides, smoking was an independent predictor of a rapid decline in the FEV₁/FVC. The annual decline in FEV₁ and FVC was significantly greater in participants with remitted childhood asthma than in healthy controls, and the differences remained significant after adjusting for the propensity score.

CONCLUSION

A history of clinically remitted childhood asthma is an independent risk factor for accelerated decline in lung function in adults. Remitted childhood asthma and smoking may additively accelerate the development of obstructive lung disease.

Revisiting Mild Asthma: Current Knowledge and Future Needs

Asthma is a common chronic airways disease with significant impact on patients, caregivers, and the health-care system. Although most research and novel interventions mainly have focused on patients with uncontrolled severe asthma, most patients with asthma have mild disease. Epidemiologic studies suggest that many patients with mild asthma report frequent exacerbations of the disease and uncontrolled symptoms. However, despite its impact, mild asthma does not have either a uniformly agreed on definition for or a consensus on its clinical and pathophysiologic progression. More recently, the approach to treatment of patients with mild asthma has undergone significant changes primarily based on emerging evidence that airway inflammation in this population is important. This led to clinical research studies that explored the efficacy of as-needed inhaled corticosteroids along with the rescue medications that traditionally have been the mainstay of treatment. Despite some advancement in the field in recent years, many controversies and unmet needs remain. In this review, we examine the current understanding of the pathophysiologic features and management of mild asthma. In addition, we outline unmet needs for future research. We conclude that mild asthma contributes significantly to the morbidity and mortality of asthma and should be the focus of future research.

Concurrence of elevated FeNO and airway hyperresponsiveness in nonasthmatic adolescents

OBJECTIVES

The aim of this study was to investigate airway responsiveness and eosinophil and neutrophil inflammatory markers in clinically confirmed nonasthmatic adolescents with elevated fractional exhaled nitric oxide (FeNO), a marker of type-2 inflammation in the airways.

METHODOLOGY

A total of 959 subjects from a general population, aged 12 to 15 years, answered a standardised questionnaire and underwent FeNO measurements at a screening visit at school. Adolescents without asthma, who had elevated FeNO (FeNO₁₀₀  > 15 ppb) (n = 19), and control subjects, with low FeNO (FeNO₁₀₀  < 5 ppb) and without reported symptoms of asthma or allergy (n = 28), participated in a follow-up study where FeNO₅₀ , airway responsiveness to methacholine (PD₂₀ ), blood eosinophil counts, and serum neutrophil lipocalin (HNL) and myeloperoxidase (MPO) levels were measured. Questionnaire follow-ups were performed 4 and 16 years later.

RESULTS

Airway responsiveness (PD₂₀ : 6.94 [1.87, 11.39] vs 11.42 [6.33, 59.4] µmol; P < .05) and blood eosinophil counts (0.31 [0.20, 0.44] vs 0.13 [0.1, 0.22] 10⁹ /L; P < .001) (geometric mean [95% CI]) were higher among cases than controls. A significant correlation between blood eosinophils and FeNO was found (rho = 0.41; P = .005). In contrast, serum HNL and MPO were lower in cases than controls (P < .05 both), and there was a negative correlation between HNL and FeNO (r = -0.31; P = .04). At both follow-ups, a higher proportion of subjects reported allergic symptoms compared with baseline (P = .02, P = .01).

CONCLUSIONS

Elevated FeNO in nonasthmatic adolescents was associated with airway hyperresponsiveness, elevated blood eosinophil counts, and lower systemic activation of neutrophils.

Effect of asthma exacerbation during pregnancy in women with asthma: a population-based cohort study

The association between asthma exacerbation during pregnancy and adverse maternal and child health outcomes have not been investigated appropriately. Our objective was to determine the short- and long-term intergenerational effect of asthma exacerbation in pregnant women with asthma.A population cohort study was conducted using data from the Ontario asthma surveillance system and population-level health administrative data. Asthma exacerbation in pregnant women with asthma was defined as at least one of the following criteria: at least five physician visits, or one emergency department visit or one hospital admission for asthma during pregnancy. Pregnancy complications, adverse perinatal outcomes and early childhood respiratory disorders were identified using International Classification of Disease codes (9th and 10th revisions).The cohort consisted of 103 424 singleton pregnancies in women with asthma. Asthma exacerbation in pregnant women with asthma was associated with higher odds of pre-eclampsia (OR 1.30, 95% CI 1.12-1.51) and pregnancy-induced hypertension (OR 1.17, 95% CI 1.02-1.33); babies had higher odds of low birthweight (OR 1.14, 95% CI 1.00-1.31), preterm birth (OR 1.14, 95% CI 1.01-1.29) and congenital malformations (OR 1.21, 95% CI 1.05-1.39). Children born to women with asthma exacerbation during pregnancy had elevated risk of asthma (OR 1.23, 95% CI 1.13-1.33) and pneumonia (OR 1.12, 95% CI 1.03-1.22) during the first 5 years of life.Asthma exacerbation during pregnancy in women with asthma showed increased risk of pregnancy complications, adverse perinatal outcomes and early childhood respiratory disorders in their children, indicating that appropriate asthma management may reduce the risk of adverse health outcomes.

Airway reversibility and inflammation in stable pre- to late-adolescent asthmatics without long-term control medications

Objective: Pulmonary function and airway inflammation were investigated in stable pre- to late-adolescent asthmatics without long-term control medications and compared with those in currently medicated asthmatics.Methods: Subjects comprised 34 well-controlled asthmatic children (aged 8.1-18.0 years; group without medication). Flow volume curves before and after inhaling a β2 agonist, a bronchodilator (BD), were compared and fractional exhaled nitric oxide (FENO) concentrations were measured. All patients were attack-free for at least 12 months prior to testing without the use of asthma medications for at least three months. Fifty-one age-matched stable asthmatics with medications at the time of the present study (group with current medication) underwent the same examinations.Results: The rate of children whose respiratory function after BD improved by 20% or more in both the central and peripheral airways (High responder at total airways subtype: HTA) was significantly higher in the group without medication than in that with current medication (17.6 and 2.0%, respectively; p < 0.01). Furthermore, FEV_1.0% pred after BD was significantly lower for HTA than for the low responder subtype in the same group (94.8 ± 3.5 and 104.1 ± 1.5% respectively, p < 0.05). FENO concentrations in the group without medication were high, but not significantly different from those in the group with current medication.Conclusions: Stable asthmatic children without medication include a certain percentage of those with irreversible airflow limitation possibly due to airway remodeling. The control of daily asthma symptoms with long-term control medications may effectively prevent airway remodeling.

A review on the pathophysiology of asthma remission

Asthma is a chronic respiratory condition, which is highly prevalent worldwide. Although no cure is currently available, it is well recognized that some asthma patients can spontaneously enter remission of the disease later in life. Asthma remission is characterized by absence of symptoms and lack of asthma-medication use. Subjects in asthma remission can be divided into two groups: those in clinical remission and those in complete remission. In clinical asthma remission, subjects still have a degree of lung functional impairment or bronchial hyperresponsiveness, while in complete asthma remission, these features are no longer present. Over longer periods, the latter group is less likely to relapse. This remission group is of great scientific interest due to the higher potential to find biomarkers or biological pathways that elicit or are associated with asthma remission. Despite the fact that the definition of asthma remission varies between studies, some factors are reproducibly observed to be associated with remitted asthma. Among these are lower levels of inflammatory markers, which are lowest in complete remission. Additionally, in both groups some degree of airway remodeling is present. Still, the pathological disease state of asthma remission has been poorly investigated. Future research should focus on at least two aspects: further characterisation of the small airways and airway walls in order to determine histologically true remission, and more thorough biological pathway analyses to explore triggers that elicit this phenomenon. Ultimately, this will result in pharmacological targets that provide the potential to steer the course of asthma towards remission.

Long noncoding RNA PAGBC contributes to nitric oxide (NO) production by sponging miR-511 in airway hyperresponsiveness upon intubation

BACKGROUND AND OBJECTIVES

In this study, we aimed to study the molecular mechanisms underlying the symptoms of hyperresponsiveness during intubation.

METHOD

The value of circulating long noncoding RNA (lncRNA)-prognosis-associated gallbladder cancer (PAGBC) in the prediction of hyperresponsiveness upon intubation during general anesthesia was evaluated via the receiver operating characteristic analyses of serum miR-511, serum PAGBC, and serum nitric oxide (NO). In addition, the possible association between lncRNA-PAGBC/NOS1 messenger RNA (mRNA) and miR-511 was further validated via real-time quantitative polymerase chain reaction, immunohistochemistry assay, computational analysis, and luciferase assay. Enzyme-linked immunosorbent assay and Western blot analysis were also conducted to establish the regulatory relationship among PAGBC, miR-511, and NO synthase 1 (NOS1).

RESULTS

Compared with circulating miR-511 and serum NO, circulating PAGBC was associated with a higher predictive value. In addition, a negative correlation was found between serum miR-511 and serum PAGBC (multicorrelation coefficient: -0.5) as well as between serum miR-511 and serum NO (multicorrelation coefficient: -0.6). In addition, both lncRNA-PAGBC and NO were decreased in patients with hyperresponsiveness, whereas the levels of miR-511 and NOS1 in these patients were similar to those in normal patients. Furthermore, our computational analyses and luciferase assays validated the direct binding between miR-511 and lncRNA-PAGBC, whereas NOS1 mRNA was identified as a virtual target gene of miR-511. Moreover, in the presence of lncRNA-PAGBC, we also observed an evident increase in the levels of NOS1 and NO accompanied by an obvious decrease of miR-511 expression.

CONCLUSION

LncRNA-PAGBC downregulated the expression of miR-511, which in turn upregulated the expression of NOS1 mRNA and led to the increase in NOS1 expression, thus leading to the inhibited responsiveness (normal-responsiveness rather than hyperresponsiveness) to intubation in patients.

Tolerance to exposure to essential oils exposure in patients with allergic asthma

Background: Essential oils are volatile compounds of plant origin increasingly used by allergic and/or asthmatic subjects to purify indoor air. The active compounds of essential oils belong to terpenes, the most widespread biogenic volatile organic compounds (VOC). Although there is substantial literature showing associations between exposure to chemical VOCs and asthmatic symptoms and impaired respiratory function, the impact of essential oils in patients with asthma has never been studied. Objectives: To evaluate the safety of a purifying air spray containing 41 essential oils (PPAS) in patients with mild or moderate allergic asthma. Methods: This was a prospective open study in which 25 mild (19) and moderate (6) asthmatics were exposed to PPAS, one spray twice a day at 8 am and 8 pm in two different corners of a given subjects bedroom for 4 weeks. Before and after 4 weeks of exposure, fractional exhaled nitric oxide (FeNO), lung function and methacholine challenge (PD₂₀) were performed and asthma control was assessed by the 5 questions of the Asthma Control Test (ACT). The spray was weighed after the 4-week exposure to assess compliance. Results: FeNO was the primary endpoint and was thus analyzed in all (N = 25) subjects irrespective of the level of airflow obstruction. The results apply to all (N = 25) subjects in which FeNO could be measured at D1 and D30 (17 subjects). Mean (SD) FeNO amounted to 37.4 (16.6) and to 33.1 (18.7) ppm before and after PPAS exposure, respectively (p = 0.09). No significant change in lung function and methacholine responsiveness was noted after PPAS exposure, the mean PD₂₀ amounting to 1179 (1124.42) μg (range 100-3200) before and to 1226 (1189.8) μg (p = 0.06) after. The mean ACT before and after PPAS exposure amounted to 20.9 (4.2) and 21 (5.15), respectively (p = 0.80). The mean weight of the PPAS bottles was 211.4 g (DS:0) before the first use and 171.41 g (DS: 29.8) at the end of the study. The average amount of PPAS used was 40.0 g (29.8). In the subgroup of subjects who used the highest quantities of essential oils (>40 g), as assessed by the mean weight of the bottle at the end of the study, FeNO after 30 days of exposure decreased more than in the entire group: 7.9 ppm vs 4.2 ppm (p = 0.07). Conclusion: No difference was noted on airway inflammation, lung function or asthma control in mild and moderate allergic asthmatics after exposure twice a day for one month, to a spray containing a mixture of 41 essential oils.

Severe asthma exists despite suppressed tissue inflammation: findings of the U-BIOPRED study

The U-BIOPRED study is a multicentre European study aimed at a better understanding of severe asthma. It included three steroid-treated adult asthma groups (severe nonsmokers (SAn group), severe current/ex-smokers (SAs/ex group) and those with mild-moderate disease (MMA group)) and healthy controls (HC group). The aim of this cross-sectional, bronchoscopy substudy was to compare bronchial immunopathology between these groups.In 158 participants, bronchial biopsies and bronchial epithelial brushings were collected for immunopathologic and transcriptomic analysis. Immunohistochemical analysis of glycol methacrylate resin-embedded biopsies showed there were more mast cells in submucosa of the HC group (33.6 mm^-2) compared with both severe asthma groups (SAn: 17.4 mm^-2, p<0.001; SAs/ex: 22.2 mm^-2, p=0.01) and with the MMA group (21.2 mm^-2, p=0.01). The number of CD4⁺ lymphocytes was decreased in the SAs/ex group (4.7 mm^-2) compared with the SAn (11.6 mm^-2, p=0.002), MMA (10.1 mm^-2, p=0.008) and HC (10.6 mm^-2, p<0.001) groups. No other differences were observed.Affymetrix microarray analysis identified seven probe sets in the bronchial brushing samples that had a positive relationship with submucosal eosinophils. These mapped to COX-2 (cyclo-oxygenase-2), ADAM-7 (disintegrin and metalloproteinase domain-containing protein 7), SLCO1A2 (solute carrier organic anion transporter family member 1A2), TMEFF2 (transmembrane protein with epidermal growth factor like and two follistatin like domains 2) and TRPM-1 (transient receptor potential cation channel subfamily M member 1); the remaining two are unnamed.We conclude that in nonsmoking and smoking patients on currently recommended therapy, severe asthma exists despite suppressed tissue inflammation within the proximal airway wall.

Clinically remitted childhood asthma is associated with airflow obstruction in middle-aged adults

BACKGROUND AND OBJECTIVE

While adult asthma has been shown to be a risk factor for COPD, the effect of remitted childhood asthma on adult lung function has not been clarified. The aim of this study was to examine whether remitted childhood asthma is a risk factor for airflow obstruction in a middle-aged general population.

METHODS

A total of 9896 participants (range: 35-60 years) from five healthcare centres were included in the study. The participants were classified into four categories based on the presence or absence of physician-diagnosed childhood/adulthood asthma and asthma symptoms as follows: healthy controls (n = 9154), remitted childhood asthma (n = 287), adulthood-onset asthma (n = 354) and childhood-adulthood asthma (n = 101).

RESULTS

The prevalence of respiratory symptoms was similar in both the participants with remitted childhood asthma and healthy controls. The prevalence of airflow obstruction (forced expiratory volume in 1 s (FEV₁ )/forced vital capacity (FVC) < 0.7) was significantly higher in the participants with remitted childhood asthma, those with adult-onset asthma and those with childhood-adulthood asthma (5.2%, 14.4% and 16.8%, respectively) compared with healthy controls (2.2%). Multivariate logistic regression showed that remitted childhood asthma was independently associated with airflow obstruction. Among the participants with remitted childhood asthma, ever-smokers had significantly lower FEV₁ /FVC than never-smokers.

CONCLUSION

Clinically remitted childhood asthma is associated with airflow obstruction in middle-aged adults. Smoking and remitted childhood asthma may be additive factors for the development of airflow obstruction.

Association of longitudinal fractional exhaled nitric oxide measurements with asthma control in atopic children

OBJECTIVES

We sought to determine whether longitudinal measurements of FeNO are informative for future loss of asthma control in children with atopic asthma.

METHODS

One hundred seventy-eight patients aged 8-16 years with atopic asthma were enrolled. FeNO and lung functions were serially monitored 10 times or more over 2 years when subjects were not receiving controller medications. After completion of monitoring, 1-year observation on the occurrence of loss of asthma control was performed and associations of loss of asthma control with spirometric and FeNO measurements were analyzed.

RESULTS

Loss of asthma control occurred during observation periods in 110 (76%) of 145 patients who completed the study. Of all monitored parameters including airway reactivity, the highest FeNO of serial measurements (H-FeNO) (adjusted odds ratio (aOR), 1.21; 95% CI, 1.08-1.36) and the rate of FeNO levels higher than 21 ppb (R21FeNO) (aOR, 1.06; 95% CI, 1.01-1.11) were the only independent predictors of upcoming control loss in the multiple logistic regression analysis. In receiver-operator characteristic curve analysis, H-FeNO > 37 ppb and R21FeNO > 20% demonstrated 91% and 88% sensitivity for a future loss of asthma control at the cost of low specificity (60% and 65%, respectively). In contrast, H-FeNO > 47 ppb and R21FeNO > 41% gave 96% and 88% specificity, but these sacrificed sensitivity to 70% and 72%, respectively.

CONCLUSIONS

Our data show that both amount and frequency of a FeNO increase during longitudinal monitoring are helpful in predicting asthma control status.

Exhaled nitric oxide and the management of childhood asthma--yet another promising biomarker "has been" or a misunderstood gem

Childhood asthma is a common chronic condition. Approximately five percent of all children in western countries are prescribed treatment with inhaled corticosteroids (ICS) to prevent asthma symptoms. Current guidelines advocate titrating ICS dose to symptoms but this approach is not without problem, e.g. how to discern asthmatic from non-asthmatic symptoms? And when to reduce ICS dose? This review describes the strengths and weaknesses of fractional exhaled nitric oxide (FENO) as an objective index for individualising asthma control in children. Epidemiological and mechanistic evidence suggest that FENO should be a promising biomarker for eosinophilic airway inflammation (a hall mark for asthma) but somewhat surprisingly, clinical trials in children have not consistently found benefit from adding FENO to a symptom-based approach to ICS treatment in children. There are a number of reasons why FENO has apparently failed to translate from promising biomarker to clinically useful tool, and one reason may be a lack of understanding of what merits a significant intrasubject change in FENO. This review describes the rise and apparent fall of FENO as biomarker for asthma and then focuses on more recent evidence which suggest that FENO may prove to have a role in the management of childhood asthma, and in particular preventing exacerbations.

Association of short-term increases in ambient air pollution and timing of initial asthma diagnosis among Medicaid-enrolled children in a metropolitan area

OBJECTIVE

We investigated associations of short-term changes in ambient ozone (O3), fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and the timing of new-onset asthma, using a large, high-risk population in an area with historically high ozone levels.

METHODS

The study population included 18,289 incident asthma cases identified among Medicaid-enrolled children in Harris County Texas between 2005-2007, using Medicaid Analytic Extract enrollment and claims files. We used a time-stratified case-crossover design and conditional logistic regression to assess the effect of increased short-term pollutant concentrations on the timing of asthma onset.

RESULTS

Each 10 ppb increase in ozone was significantly associated with new-onset asthma during the warm season (May-October), with the strongest association seen when a 6-day cumulative average period was used as the exposure metric (odds ratio [OR]=1.05, 95% confidence interval [CI], 1.02-1.08). Similar results were seen for NO2 and PM2.5 (OR=1.07, 95% CI, 1.03-1.11 and OR=1.12, 95% CI, 1.03-1.22, respectively), and PM2.5 also had significant effects in the cold season (November-April), 5-day cumulative lag (OR=1.11. 95% CI, 1.00-1.22). Significantly increased ORs for O3 and NO2 during the warm season persisted in co-pollutant models including PM2.5. Race and age at diagnosis modified associations between ozone and onset of asthma.

CONCLUSION

Our results indicate that among children in this low-income urban population who developed asthma, their initial date of diagnosis was more likely to occur following periods of higher short-term ambient pollutant levels.

What is asthma? Pathophysiology, demographics, and health care costs

Asthma is an obstructive pulmonary disorder with exacerbations characterized by symptoms of shortness of breath, cough, chest tightness, and/or wheezing. Symptoms are caused by chronic airway inflammation. There are multiple cell types and inflammatory mediators involved in its pathophysiology. The airway inflammation is frequently mediated by Th2 lymphocytes, whose cytokine secretion leads to mast cell stimulation, eosinophilia, leukocytosis, and enhanced B-cell IgE production. Although various genes have been identified as likely contributors to asthma development, asthma is largely environmentally triggered and has a multifactorial cause. Asthma is extremely common, especially in poor, urban environments. Asthma is the third most common reason for pediatric hospitalizations.

Breath tests in respiratory and critical care medicine: from research to practice in current perspectives

Today, exhaled nitric oxide has been studied the most, and most researches have now focused on asthma. More than a thousand different volatile organic compounds have been observed in low concentrations in normal human breath. Alkanes and methylalkanes, the majority of breath volatile organic compounds, have been increasingly used by physicians as a novel method to diagnose many diseases without discomforts of invasive procedures. None of the individual exhaled volatile organic compound alone is specific for disease. Exhaled breath analysis techniques may be available to diagnose and monitor the diseases in home setting when their sensitivity and specificity are improved in the future.

The long-term outcomes of persistent childhood allergic asthma: a cross-sectional study from western Anatolia: childhood persistent asthma in western Anatolia

BACKGROUND

Prospective cohort studies have provided useful knowledge about the natural history of asthma. However, most of the studies are conducted in western countries but the course of the disease and long-term outcomes may differ between countries due to environmental and cultural factors.

OBJECTIVE

The aim of this study is to describe the long-term outcomes of childhood asthma, with data from a follow-up study of at least 10 years, in western Anatolia, Turkey.

METHODS

Fifty-two patients diagnosed with persistent allergic asthma participated in the study. The patient's demographics, findings on admission, age at onset of disease, time of diagnosis, history of other allergic conditions, history of parental asthma and allergic disorders, presence of pharmacotherapy and immunotherapy were obtained from patients' records. The factors influencing remission at the end of 10 years follow-up were evaluated.

RESULTS

A total of 20 patients (38.5%) were on remission at the end of 10 years. The type of allergen, multi-allergen sensitivity, eosinophilia and elevated serum immunoglobulin E on admission, accompanying allergic disorders and atopy in parents, and allergen immunotherapy did not affect the remission rate (p>0.05).

CONCLUSION

Childhood persistent asthma is not a homogeneous clinical entity but high clinical remission rates are obtained in western Anatolia. There is no significant predictor of clinical remission in long term follow-up. Prospective studies should be performed in larger asthmatic populations to obtain further data about the natural course of childhood asthma.

Nasal nitric oxide is a marker of poor asthma control

Asthma control, evaluated by symptoms, exacerbations rate and lung function may be greatly influenced by comorbidities, particularly chronic rhinosinusitis (CRS). Measurement of nasal nitric oxide (nNO) is a simple way to assess the severity of CRS. We aimed to analyze the relationship between asthma control and nasal NO. All patients with moderate-to-severe asthma on regular follow-up at our Outpatients' Clinic between November 2009 and April 2010 were included into the study. All patients were evaluated for asthma control by asthma control questionnaire (ACQ) and comorbidities (rhinitis, chronic rhinosinusitis with (CRSwNP) or without nasal polyps, obesity). Exhaled nitric oxide and nNO were obtained in all patients. Eighty-two patients were enrolled (mean age: 48 years, range: 21-80; 42 females). According to ACQ, 53 patients (64.6%) reported controlled asthma. Patients with uncontrolled asthma had lower nNO and higher prevalence of CRSwNP, with a significant correlation between nNO and ACQ. nNO is a biomarker negatively related to asthma control. As low nNO values were associated to CRSwNP, our results indicate that asthma control is highly influenced by this comorbidity.

Exhaled nitric oxide indicates poorly athlete's asthma

INTRODUCTION

In athletes, exercise-induced respiratory symptoms are common and their assessment is time and resource consuming.

OBJECTIVE

The objective was to evaluate fractional concentration of exhaled nitric oxide (FENO) as a predictor of bronchial hyperresponsiveness (BHR) and of asthma.

MATERIALS AND METHODS

Eighty-seven elite athletes and a control group of 87 sedentary patients with symptoms suggesting asthma underwent measurements of FENO and of BHR by using methacholine provocation test (MCH) and eucapnic voluntary hyperpnoea (EVH) (athletes) or histamine provocation test (HIST) (controls).

RESULTS

In athletes, elevated FENO (>30 ppb) was not associated with lung function-confirmed asthma or with MCH positivity, but receiver operating characteristics (ROC) analysis showed some predictive value for EVH positivity [Area Under Curve (AUC) 0.652, 95% confidence interval (CI): 0.53 to 0.78, P = 0.020]. However, the sensitivity (55%) and the specificity (71%) were poor. In sedentary patients, FENO was significantly associated with both confirmed asthma and HIST positivity, ROC analysis showing FENO to be significantly predictive for HIST positivity (AUC 0.83, 95% CI: 0.70 to 0.96, P = 0.001) and for asthma (AUC 0.74, 95% CI: 0.63 to 0.85, P < 0.001).

CONCLUSION

The results suggest that in contrast to sedentary patients, FENO seems to be a poor predictor of BHR and of clinical asthma in elite athletes. We find it unlikely that FENO could be a useful screening tool in athletes with exercise-induced respiratory symptoms.

The air quality health index and asthma morbidity: a population-based study

BACKGROUND

Exposure to air pollution has been linked to the exacerbation of respiratory diseases. The Air Quality Health Index (AQHI), developed in Canada, is a new health risk scale for reporting air quality and advising risk reduction actions.

OBJECTIVE

We used the AQHI to estimate the impact of air quality on asthma morbidity, adjusting for potential confounders.

METHODS

Daily air pollutant measures were obtained from 14 regional monitoring stations in Ontario. Daily counts of asthma-attributed hospitalizations, emergency department (ED) visits, and outpatient visits were obtained from a provincial registry of 1.5 million patients with asthma. Poisson regression was used to estimate health services rate ratios (RRs) as a measure of association between the AQHI or individual pollutants and health services use. We adjusted for age, sex, season, year, and region of residence.

RESULTS

The AQHI values were significantly associated with increased use of asthma health services on the same day and on the 2 following days, depending on the specific outcome assessed. A 1-unit increase in the AQHI was associated with a 5.6% increase in asthma outpatient visits (RR = 1.056; 95% CI: 1.053, 1.058) and a 2.1% increase in the rate of hospitalization (RR = 1.021; 95% CI: 1.014, 1.028) on the same day and with a 1.3% increase in the rate of ED visits (RR = 1.013; 95% CI: 1.010, 1.017) after a 2-day lag.

CONCLUSIONS

The AQHI values were significantly associated with the use of asthma-related health services. Timely AQHI health risk advisories with integrated risk reduction messages may reduce morbidity associated with air pollution in patients with asthma.

Differences in airway inflammation according to atopic status in patients with chronic rhinitis

Background

Chronic rhinitis is a heterogeneous group of diseases that cause nasal inflammation. And the nose may be a window into the lung in the concept of "one airway one disease."

Objective

This study was conducted to evaluate differences between the different forms of chronic rhinitis in terms of lower airway inflammation.

Methods

Patients that attended the allergy clinic and presented with moderate/severe persistent rhinitis symptoms for more than 1 year were enrolled. The patients with chronic rhinitis were classified into two groups (house dust mites [HDM]-sensitive allergic rhinitis [AR] or non-allergic rhinitis [NAR]) according to the presence of atopy, and additionally according to nasal polyposis and airway hyperresponsiveness, respectively. Medical records were reviewed and the mRNA expression levels of IL-5, IFN-γ, TGF-β1, IL-17A, and IL-25 were evaluated in induced sputum samples in each group.

Results

Induced sputum samples of 53 patients were evaluated. Patients with NAR were significantly older than patients with HDM-sensitive AR (p < 0.05). Nasal polyposis was more prevalent in NAR patients than in HDM-sensitive AR patients (10.2% vs. 62.5%, p < 0.001). The expression levels of IL-17A mRNA were higher in NAR patients, regardless of the presence of airway hyperresponsiveness (p = 0.005).

Conclusion

These results suggest that patients with different forms of chronic rhinitis could have different inflammatory environments in their lower airway and NAR patients might have bronchial inflammation related to the elevated levels of IL-17A compared to HDM-sensitive AR patients.

Fractional exhaled nitric oxide and forced expiratory flow between 25% and 75% of vital capacity in children with controlled asthma

Purpose

Fractional exhaled nitric oxide (FeNO) and forced expiratory flow between 25% and 75% of vital capacity (FEF_25-75) are not included in routine monitoring of asthma control. We observed changes in FeNO level and FEF_25-75 after FeNO-based treatment with inhaled corticosteroid (ICS) in children with controlled asthma (CA).

Methods

We recruited 148 children with asthma (age, 8 to 16 years) who had maintained asthma control and normal forced expiratory volume in the first second (FEV₁) without control medication for ≥3 months. Patients with FeNO levels >25 ppb were allocated to the ICS-treated (FeNO-based management) or untreated group (guideline-based management). Changes in spirometric values and FeNO levels from baseline were evaluated after 6 weeks.

Results

Ninety-three patients had FeNO levels >25 ppb. These patients had lower FEF_25-75% predicted values than those with FeNO levels ≤25 ppb (P<0.01). After 6 weeks, the geometric mean (GM) FeNO level in the ICS-treated group was 45% lower than the baseline value, and the mean percent increase in FEF_25-75 was 18.% which was greater than that in other spirometric values. There was a negative correlation between percent changes in FEF_25-75 and FeNO (r=-0.368, P=0.001). In contrast, the GM FeNO and spirometric values were not significantly different from the baseline values in the untreated group.

Conclusion

The anti-inflammatory treatment simultaneously improved the FeNO levels and FEF_25-75 in CA patients when their FeNO levels were >25 ppb.

Comparison of physician-, biomarker-, and symptom-based strategies for adjustment of inhaled corticosteroid therapy in adults with asthma: the BASALT randomized controlled trial

CONTEXT

No consensus exists for adjusting inhaled corticosteroid therapy in patients with asthma. Approaches include adjustment at outpatient visits guided by physician assessment of asthma control (symptoms, rescue therapy, pulmonary function), based on exhaled nitric oxide, or on a day-to-day basis guided by symptoms.

OBJECTIVE

To determine if adjustment of inhaled corticosteroid therapy based on exhaled nitric oxide or day-to-day symptoms is superior to guideline-informed, physician assessment-based adjustment in preventing treatment failure in adults with mild to moderate asthma.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, parallel, 3-group, placebo-controlled, multiply-blinded trial of 342 adults with mild to moderate asthma controlled by low-dose inhaled corticosteroid therapy (n = 114 assigned to physician assessment-based adjustment [101 completed], n = 115 to biomarker-based [exhaled nitric oxide] adjustment [92 completed], and n = 113 to symptom-based adjustment [97 completed]), the Best Adjustment Strategy for Asthma in the Long Term (BASALT) trial was conducted by the Asthma Clinical Research Network at 10 academic medical centers in the United States for 9 months between June 2007 and July 2010.

INTERVENTIONS

For physician assessment-based adjustment and biomarker-based (exhaled nitric oxide) adjustment, the dose of inhaled corticosteroids was adjusted every 6 weeks; for symptom-based adjustment, inhaled corticosteroids were taken with each albuterol rescue use.

MAIN OUTCOME MEASURE

The primary outcome was time to treatment failure.

RESULTS

There were no significant differences in time to treatment failure. The 9-month Kaplan-Meier failure rates were 22% (97.5% CI, 14%-33%; 24 events) for physician assessment-based adjustment, 20% (97.5% CI, 13%-30%; 21 events) for biomarker-based adjustment, and 15% (97.5% CI, 9%-25%; 16 events) for symptom-based adjustment. The hazard ratio for physician assessment-based adjustment vs biomarker-based adjustment was 1.2 (97.5% CI, 0.6-2.3). The hazard ratio for physician assessment-based adjustment vs symptom-based adjustment was 1.6 (97.5% CI, 0.8-3.3).

CONCLUSION

Among adults with mild to moderate persistent asthma controlled with low-dose inhaled corticosteroid therapy, the use of either biomarker-based or symptom-based adjustment of inhaled corticosteroids was not superior to physician assessment-based adjustment of inhaled corticosteroids in time to treatment failure.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00495157.

Asthma outcomes: biomarkers

BACKGROUND

Measurement of biomarkers has been incorporated within clinical research studies of asthma to characterize the population and associate the disease with environmental and therapeutic effects.

OBJECTIVE

National Institutes of Health institutes and federal agencies convened an expert group to propose which biomarkers should be assessed as standardized asthma outcomes in future clinical research studies.

METHODS

We conducted a comprehensive search of the literature to identify studies that developed and/or tested asthma biomarkers. We identified biomarkers relevant to the underlying disease process progression and response to treatment. We classified the biomarkers as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Ten measures were identified; only 1, multiallergen screening to define atopy, is recommended as a core asthma outcome. Complete blood counts to measure total eosinophils, fractional exhaled nitric oxide (Feno), sputum eosinophils, urinary leukotrienes, and total and allergen-specific IgE are recommended as supplemental measures. Measurement of sputum polymorphonuclear leukocytes and other analytes, cortisol measures, airway imaging, breath markers, and system-wide studies (eg, genomics, proteomics) are considered as emerging outcome measures.

CONCLUSION

The working group participants propose the use of multiallergen screening in all asthma clinical trials to characterize study populations with respect to atopic status. Blood, sputum, and urine specimens should be stored in biobanks, and standard procedures should be developed to harmonize sample collection for clinical trial biorepositories.

Viewpoint: the future of research in pediatric allergy: what should the focus be?

Allergic diseases have been increasing during the last three decades, and exact reasons for this are still debated. Despite intense ongoing research, a lot of aspects of allergic diseases are still poorly understood, resulting in limitations in current therapeutic approach to allergies. In this viewpoint, important unanswered research questions are raised mainly on novel therapeutic approaches to allergic children, and suggestions for future research are raised. Three aspects of pediatric allergy are distinguished: the prevention, control, and cure.

Fractional exhaled nitric oxide measurements in rhinitis and asthma in children

Exaled nitric oxide (FeNO) is considered a good noninvasive marker to assess airway inflammation in asthma and allergic rhinitis. In asthma, exhaled NO is very useful to verify adherence to therapy, and to predict upcoming asthma exacerbations. It has been also proposed that adjusting anti-inflammatory drugs guided by the monitoring of exhaled NO, could improve overall asthma control. Other studies showed increased FeNO levels in subjects with allergic rhinitis.

Comparison of bronchial hyperresponsiveness to methacholine and adenosine and airway inflammation markers in patients with suspected asthma

BACKGROUND

Bronchial hyperresponsiveness is usually measured by bronchial challenge test with direct (e.g., methacholine) and indirect (e.g., adenosine) agonists. There are few studies comparing both types of agents and they have had conflicting concordance.

OBJECTIVE

We sought to compare the results of both tests in a population with symptoms suggestive of asthma so as to determine their relationship with bronchial inflammatory markers.

METHODS

Seventy-nine patients whose age ranged from 14 to 81 years were recruited for this study. Challenge tests were performed using the tidal volume method. PC₂₀ methacholine and PC₁₅ and PC₂₀ adenosine were calculated. Induced sputum and fraction of exhaled nitric oxide measurements were also performed.

RESULTS

Atopy was found in 69% of the patients. Methacholine PC₂₀ and adenosine PC₁₅ were positive in 32 patients (40.5%), both having a sensitivity of 73%. Percentage of agreement was 45.45% and κ index was only 0.369. Adenosine PC₂₀ elicited lower sensitivity and agreement. No correlation between methacholine PC₂₀ and adenosine PC₁₅ was observed. Higher fraction of exhaled nitric oxide values and sputum eosinophil counts were seen in patients with positive adenosine challenge results. The use of adenosine PC₁₅ or PC₂₀ did not alter the association with inflammatory markers.

CONCLUSIONS

The concordance between both techniques was low. Methacholine is not a reliable predictor of hyperresponsiveness to adenosine, leading us to conclude that the two tests are complementary but not interchangeable in clinical practice. Additionally, responsiveness to the two bronchoconstrictor stimuli does not indicate presence of the same airway abnormality. Indirect stimuli provide a better reflection of bronchial inflammation.

Subclinical airway inflammation despite high-dose oral corticosteroid therapy in cats with lower airway disease

Management of feline chronic lower airway disease focuses on controlling clinical signs and decreasing airway inflammation. This retrospective study evaluated the correlation between the resolution of clinical signs in cats with lower airway disease receiving oral glucocorticoids with the resolution of inflammation based on bronchoalveolar lavage fluid (BALF) cytology. Ten cats diagnosed with lower airway disease based on characteristic clinical signs and inflammatory BALF cytology received oral glucocorticoids for at least 3 weeks. They were required to have resolution of clinical signs and BALF collected while asymptomatic and still receiving glucocorticoids. Cats received prednisolone or prednisone (average dose of 1.8±0.2mg/kg daily) for 35.7±5.5 days. Three cats had resolution of clinical signs and lacked inflammatory BALF cytology; seven had persistent inflammatory BALF cytology despite resolution of clinical signs. Given that subclinical inflammation during high-dose glucocorticoid treatment was common, current recommendations to taper therapy based on resolution of clinical signs should be re-evaluated.

The role of measuring airway hyperresponsiveness and inflammatory biomarkers in asthma

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

Using biomarkers in the assessment of airways disease

A biomarker provides a window on underlying disease activity. This is helpful when the pathology, treatment response, or both are heterogeneous or when trying to interpret nonspecific respiratory symptoms in patients with comorbidities. The successful application of a biomarker result is critically dependent on the specific question being addressed and the performance characteristics of the biomarker in relation to that question in the context of pretest probabilities. Negative prediction might be the best way to use a biomarker, such as a D-dimer, pro-brain natriuretic peptide, and exhaled nitric oxide. In this review the role of biomarkers in airways disease (notably induced sputum eosinophils and exhaled nitric oxide) is considered in relation to risk stratification, identification of treatment responders, identification of a clinical phenotype, monitoring of disease, and new drug development.

Sensitivity to environmental irritants and capsaicin cough reaction in patients with a positive methacholine provocation test before and after treatment with inhaled corticosteroids

BACKGROUND

Increasing evidence points to a potential role for members of the transient receptor potential family of cation channels on several features of asthmatic disease. The cough sensitivity to inhaled capsaicin is known to reflect the reactivity of these airway sensory nerves.

OBJECTIVE

The aim was to study, among patients having a positive methacholine provocation and diagnosed with asthma, capsaicin cough sensitivity, sensitivity to methacholine, and levels of exhaled nitric oxide before and after treatment with inhaled steroids, and further, to measure the self-reported impact from environmental irritants.

METHODS

Eighteen steroid-naïve patients with a positive methacholine test underwent capsaicin inhalation provocation on two occasions, before and after regular use of inhaled steroids over at least 3 months. Comparisons were made to 21 healthy controls. Sensitivity to methacholine and levels of exhaled nitric oxide were measured before and after the treatment. The participants also answered a validated questionnaire regarding environmental irritants.

RESULTS

The patients displayed higher capsaicin cough sensitivity than the controls before the treatment period, but not afterward. Before treatment, capsaicin cough answer correlated significantly with levels of exhaled nitric oxide, but not with methacholine sensitivity. After treatment with inhaled corticosteroids, the capsaicin cough sensitivity and the inflammatory parameters were normalized. In comparison to the control group, the patients reported more affective reactions to and behavioral disruptions induced by environmental irritants.

CONCLUSIONS

In steroid-naïve patients with a positive methacholine test, there is a link between that part of the airway inflammation that is reflected by exhaled nitric oxide and that followed by an augmented reactivity of capsaicin-sensitive sensory nerves. This association disappears after steroid treatment.

Airway hyperresponsiveness to mannitol and methacholine and exhaled nitric oxide: a random-sample population study

BACKGROUND

Studies of selected patient groups have shown that airway hyperresponsiveness (AHR) to mannitol is more specific than methacholine for the diagnosis of asthma, as well as more closely associated with markers of airway inflammation in asthma.

OBJECTIVE

We sought to compare AHR to mannitol and methacholine and exhaled nitric oxide (eNO) levels in a nonselected population sample.

METHODS

In 238 young adults randomly drawn from the nationwide civil registration list in Copenhagen, Denmark, AHR to mannitol and methacholine, as well as levels of eNO, were determined, and the association with asthma was analyzed.

RESULTS

In diagnosing asthma the specificity of methacholine and mannitol was 80.2% (95% CI, 77.1% to 82.9%) and 98.4% (95% CI, 96.2% to 99.4%), respectively, with a positive predictive value of 48.6% versus 90.4%, whereas the sensitivity was 68.6% (95% CI, 57.1% to 78.4%) and 58.8% (95% CI, 50.7% to 62.6%), respectively. In asthmatic subjects AHR to mannitol was associated with increased eNO levels (positive AHR to mannitol: median, 47 ppb [interquartile range, 35-68 ppb]; negative AHR to mannitol: median, 19 ppb [interquartile range, 13-30 ppb]; P = .001), whereas this was not the case for AHR to methacholine (median of 37 ppb [interquartile range, 26-51 ppb] vs 24 ppb [interquartile range, 15-39 ppb], P = .13).

CONCLUSION

In this random population sample, AHR to mannitol was less sensitive but more specific than methacholine in the diagnosis of asthma. Furthermore, AHR to mannitol was more closely associated with ongoing airway inflammation in terms of increased eNO levels.

Trends in asthma prevalence and incidence in Ontario, Canada, 1996-2005: a population study

In the 1980s and early 1990s, asthma prevalence increased significantly in most Westernized countries. In more recent years, asthma trends have been less clear, with some studies suggesting that they are still rising and others suggesting that they have stabilized or decreased. A population-based cohort study was conducted to estimate asthma prevalence and incidence trends in one large Canadian province, Ontario. All individuals with asthma living in Ontario, a province of Canada with a multicultural population of approximately 12 million, were identified in universal, population health administrative databases by using a validated health administrative case definition of asthma. Annual asthma prevalence, incidence, and all-cause mortality rates were estimated from 1996 to 2005. During this time, the prevalence of asthma increased by 70.5%. The age- and sex-standardized asthma prevalence increased from 8.5% in 1996 to 13.3% in 2005, a relative increase of 55.1% (P < 0.0001). Asthma incidence rates increased in children by 30.0% and were relatively stable in adults. Overall all-cause mortality decreased. Asthma prevalence in Ontario, Canada, has increased significantly. This is attributable, in part, to an increase in the incidence of asthma in children. Effective clinical and public health strategies are needed to prevent and manage asthma in the population.

Can AMP induce sputum eosinophils, even in subjects with complete asthma remission?

Background

The definition of "clinical asthma remission" is based on absence of symptoms and use of medication. However, in the majority of these subjects airway inflammation is still present when measured. In the present study we investigated whether "complete asthma remission", additionally defined by the absence of bronchial hyperresponsiveness (BHR) and the presence of a normal lung function, is associated with the absence of airway inflammation.

Methods

Patients with a former diagnosis of asthma and a positive histamine provocation test were re-examined to identify subjects with complete asthma remission (no asthma symptoms or medication, PC₂₀ histamine > 32 mg/ml, FEV₁ > 90% predicted). Patients with PC₂₀ histamine ≤ 32 mg/ml were defined as current asthmatics and were divided in two groups, i.e. asthmatics with and without BHR to adenosine 5'monophoshate (AMP). Sputum induction was performed 1 week before and 1 hour after AMP provocation. Sputum induction and AMP provocation were previously shown to be sensitive markers of airway inflammation.

Results

Seven patients met criteria for complete asthma remission. Twenty-three were current asthmatics, including twelve without hyperresponsiveness to AMP. Subjects with complete asthma remission showed no AMP-induced sputum eosinophilia (median (range) 0.2 (0 - 4.6)% at baseline and 0.2 (0 - 2.6)% after AMP). After AMP, current asthmatics had a significant increase in sputum eosinophils (0.5 (0 - 26.0)% at baseline and 2.6 (0 - 32.0) % after AMP), as had the subgroup of current asthmatics without hyperresponsiveness to AMP (0.2 (0 - 1.8)% at baseline and 1.3 (0 - 6.3)% after AMP).

Conclusions

Subjects with complete asthma remission, in contrast to subjects with current asthma, do not respond with eosinophilic inflammation in sputum after AMP provocations. These data lend support to the usefulness of the definition of complete asthma remission.

Associations of airway inflammation and responsiveness markers in non asthmatic subjects at start of apprenticeship

Background

Bronchial Hyperresponsiveness (BHR) is considered a hallmark of asthma. Other methods are helpful in epidemiological respiratory health studies including Fractional Exhaled Nitric Oxide (FENO) and Eosinophils Percentage (EP) in nasal lavage fluid measuring markers for airway inflammation along with the Forced Oscillatory Technique measuring Airway resistance (AR). Can their outcomes discriminate profiles of respiratory health in healthy subjects starting apprenticeship in occupations with a risk of asthma?

Methods

Rhinoconjunctivitis, asthma-like symptoms, FEV1 and AR post-Methacholine Bronchial Challenge (MBC) test results, FENO measurements and EP were all investigated in apprentice bakers, pastry-makers and hairdressers not suffering from asthma. Multiple Correspondence Analysis (MCA) was simultaneously conducted in relation to these groups and this generated a synthetic partition (EI). Associations between groups of subjects based on BHR and EI respectively, as well as risk factors, symptoms and investigations were also assessed.

Results

Among the 441 apprentice subjects, 45 (10%) declared rhinoconjunctivitis-like symptoms, 18 (4%) declared asthma-like symptoms and 26 (6%) suffered from BHR. The mean increase in AR post-MBC test was 21% (sd = 20.8%). The median of FENO values was 12.6 ppb (2.6-132 range). Twenty-six subjects (6.7%) had EP exceeding 14%. BHR was associated with atopy (p < 0.01) and highest FENO values (p = 0.09). EI identified 39 subjects with eosinophilic inflammation (highest values of FENO and eosinophils), which was associated with BHR and atopy.

Conclusions

Are any of the identified markers predictive of increased inflammatory responsiveness or of development of symptoms caused by occupational exposures? Analysis of population follow-up will attempt to answer this question.

Severe Asthma in Children: Insights from the National Heart, Lung, and Blood Institute's Severe Asthma Research Program

Severe asthma in children is a complicated disorder characterized by ongoing symptoms and persistent airway inflammation despite treatment with high doses of inhaled and oral corticosteroids. Although knowledge of asthma and its associated mechanisms has increased substantially over the past decade, significant gaps remain about the determinants of severe asthma in children and the progression of the disorder across the lifespan. This review highlights recent insights into severe asthma in children derived from the National Heart, Lung, and Blood Institute's Severe Asthma Research Program (SARP), with an emphasis on age-specific findings and differences from severe asthma in adults. While the existence of a true severe asthma phenotype in children is subject to some debate, given the results of SARP and other investigators, we conclude that there is indeed a subgroup of children with severe asthma who have extreme morbidity and differentiating clinical features that are identifiable very early in life. However, unlike adults with severe asthma, children with severe asthma are more likely to fall in a more narrow cluster that is characterized by marked atopy and reversible airflow obstruction. While SARP has advanced knowledge of severe asthma in children, considerable gaps remain for which additional studies are needed.

Exhaled nitric oxide and airway hyperresponsiveness in workers: a preliminary study in lifeguards

Background

Airway inflammation and airway hyperresponsiveness (AHR) are two characteristic features of asthma. Fractional exhaled nitric oxide (FENO) has shown good correlation with AHR in asthmatics. Less information is available about FENO as a marker of inflammation from work exposures. We thus examined the relation between FENO and AHR in lifeguards undergoing exposure to chloramines in indoor pools.

Methods

39 lifeguards at six indoor pools were given a respiratory health questionnaire, FENO measurements, spirometry, and a methacholine bronchial challenge (MBC) test. Subjects were labeled MBC+ if the forced expiratory volume (FEV1) fell by 20% or more. The normalized linear dose-response slope (NDRS) was calculated as the percentage fall in FEV1 at the last dose divided by the total dose given. The relation between MBC and FENO was assessed using logistic regression adjusting on confounding factors. The association between NDRS and log-transformed values of FENO was tested in a multiple linear regression model.

Results

The prevalence of lifeguards MBC+ was 37.5%. In reactors, the median FENO was 18.9 ppb (90% of the predicted value) vs. 12.5 ppb (73% predicted) in non-reactors. FENO values ≥ 60% of predicted values were 80% sensitive and 42% specific to identify subjects MBC+. In the logistic regression model no other factor had an effect on MBC after adjusting for FENO. In the linear regression model, NDRS was significantly predicted by log FENO.

Conclusions

In lifeguards working in indoor swimming pools, elevated FENO levels are associated with increased airway responsiveness.

Exhaled nitric oxide levels in asthma: Personal best versus reference values

BACKGROUND

Factors affecting the fraction of nitric oxide in exhaled air (FE(NO)) are multiple. Interpreting values when assessing airways disease may be problematic. Clinically optimum levels have not been defined.

OBJECTIVES

We aimed to establish the relationship between predicted values for FE(NO) obtained from equations by Olin et al, Travers et al, and Dressel et al, and normalized levels after oral prednisone. We also compared postprednisone FE(NO) levels with those obtained during optimized treatment with inhaled fluticasone.

METHODS

Data were obtained before and after a trial of oral prednisone (30mg/d for 14 days), and also from a previously published study in which patients had their dose of inhaled corticosteroid adjusted using either FE(NO) or symptoms/lung function to optimize treatment.

RESULTS

Seventy-three patients completed the study. The geometric mean FE(NO) after prednisone (17.7 parts per billion [ppb]; 95% CI, 15.5-20.2) was significantly lower than mean FE(NO) at the optimized fluticasone dose (20.2 ppb; 95% CI, 17.1-23.8; P=.04) and at loss of control (27.6 ppb; 95% CI, 22.8-33.4; P < .001). FE(NO) levels after prednisone did not differ significantly from the predicted values of Olin et al (16.8 ppb, 95% CI, 16.0-17.5; P=.44), but were significantly lower than values of Travers et al (predicted, 21.5 ppb; 95% CI, 20.9-22.2; P=.005) and Dressel et al (predicted, 27.8 ppb; 95% CI, 26.7-28.9; P < .001).

CONCLUSIONS

Optimum FE(NO) levels are best established by using oral rather than inhaled steroid treatment, and these approximate to predicted values from the reference equation by Olin et al. However, at optimized doses of inhaled corticosteroid, although FE(NO) levels were higher than predicted, asthma was well controlled. Targeting FE(NO) on reference values is not justified.

Fractional exhaled nitric oxide in asthma: an update

In asthma, clinical symptoms and lung function are insensitive in reflecting the underlying airway inflammation, and monitoring of this process has only recently become available. Fractional exhaled nitric oxide (Fe(NO)) is now recognized as a reliable surrogate marker of eosinophilic airway inflammation and offers the advantage of being completely non-invasive and very easy to obtain. This review summarizes the clinical use of Fe(NO) in asthma. It covers the relationship between Fe(NO) and the underlying eosinophilic inflammation, the pathophysiology and production of Fe(NO), technical aspects of Fe(NO) measurement and potential confounding factors in interpreting levels. Fe(NO) reference values and the role of Fe(NO) in asthma assessment, diagnosis and management are also discussed.

Military service-aggravated asthma improves at two-year follow-up

BACKGROUND

During military service young men (age 19-21 years) are exposed to many predisposing factors for asthma. We aimed to study the short-term prognosis of asthma after the military service.

METHODS

All 216 men with verified asthma in 2004-2005 from the register of the Central Military Hospital were included in the study. A questionnaire was mailed to them in autumn 2007 and the 146 responders (68%) formed the final study population. Asthma severity was evaluated during military service according to the medical records of the subjects and two years later based on the questionnaire using modified GINA guidelines. The results on lung function and allergy tests during military service and asthma history were used as predictors of asthma severity at two-year follow-up.

RESULTS

Two groups of asthmatics were identified: those who already had asthma when entering the military service (n=71, 48.6%) and those, who had a new onset of asthma during the service (n=75, 51.4%). Overall asthma was less severe at two-year follow-up than during military service (p=0.036). Both during military service and at two-year follow-up, asthma was milder among the men, who had a new onset of asthma during military service. Atopy (p=0.002), number of positive skin-prick tests (p=0.005) and higher total serum IgE (p=0.001) were significant predictors for persistent asthma at follow-up.

CONCLUSIONS

Asthma, which had aggravated or started during military service, was significantly less severe two years later. The degree of atopy was a major determinant of the two-year prognosis of asthma after military service.

The effect of low-dose inhaled budesonide on PC20 AMP levels in patients with mild asthma: a 3-month follow-up study

Adenosine monophosphate (AMP) challenge is a diagnostic tool for asthma. The aim of this study is to evaluate the effect of low dose inhaled budesonide (IB) on PC(20)AMP levels. Seventeen stable mild asthmatic patients were prospectively recruited. After initial testing, patients were administered 400 microg of inhaled budesonide. AMP challenge was then repeated at the 12th hour and 5th,15th, 30th, and 90th days of the treatment. AMP challenge resulted in negative in 47% of the patients at 12(-)hour testing. This study suggests that low-dose IB may return airway responsiveness as early as 12 hours and AMP challenge may be effectively used for treatment monitorization.