Concordance between bronchial hyperresponsiveness, fractional exhaled nitric oxide, and asthma control in children

Childhood severe asthma: relationship among asthma control scores, FeNO, spirometry and impulse oscillometry

INTRODUCTION

The evaluation of the asthmatic patient is usually based on clinical and functional parameters that do not necessarily evidence the degree of airway inflammation. The aim of this study was to analyze whether clinical scores (CS) correlate with spirometry (S), impulse oscillometry (IO) and FeNO, in severe asthmatic children.

MATERIAL AND METHODS

A multicentric, prospective, cross-sectional study was conducted over a 12-month period. All SA patients (6-18 years old) followed-up in the Pulmonology Department were recruited. CS, FeNO measurements, IO and S were consecutively performed on the same day. Asthma control was ascertained using ACT and GINAq. A cut-off value of ≥ 25 parts per billion (ppb) was used to define airway inflammation.

RESULTS

Eighty-one patients were included. ACT: 75% (n 61) were controlled; GINAq: 44.5% (n 36) were controlled; 39.5% (n 32) were partly controlled, and 16% (n 13) were uncontrolled. FeNO had a median value of 24 ppb (IQR 14-41); FeNO ≥ 25 ppb was observed in 49% of patients (n 39). ROC AUC for FeNO vs. ACT was 0.71 (95%CI 0.57-0.86), PPV 0.47, NPV 0.87, SE 0.61, SP 0.80; FeNO vs. GINAq was ROC AUC 0.69 (95%CI 0.54-0.85), PPV 0.34, NPV 0.91, SE 0.62, SP 0.77; Youden cut-off FeNO > 39 ppb for both CS.

CONCLUSION

In severe asthmatic children, current symptoms control as evidenced by ACT and GINA correlates with low FeNO values. Clinical scores showed good correlation with airway inflammation.

Childhood asthma treatment based on indirect hyperresponsiveness test: Randomized controlled trial

PURPOSE

The purpose of this study was to assess the usefulness of indirect airway hyperresponsiveness (AHR) test using hypertonic saline in determining the dose of inhaled corticosteroids (ICS) to maintain asthma control in children.

METHODS

A group of 104 patients (7-15 years) with mild-moderate atopic asthma were monitored for their asthma control and treatment for 1 year. Patients were randomly assigned to a symptom-only monitored group and a group with therapy changes based on the symptoms and severity of AHR. Spirometry, exhaled nitric oxide, and blood eosinophils (BEos) were assessed on enrollment and every 3 months thereafter.

RESULTS

During the study period, the number of mild exacerbations was lower in the AHR group (44 vs. 85; the absolute rate per patient 0.83 vs. 1.67; relative rate 0.49, 95% confidence interval: 0.346-0.717 (p < 0.001)]. Mean changes from baseline in clinical (except asthma control test), inflammatory, and lung function parameters were similar between groups. Baseline BEos correlated with AHR and was a risk factor for recurrent exacerbation in all patients. There was no significant difference in the final ICS dose between AHR and symptoms group: 287 (SD 255) vs. 243 (158) p = 0.092.

CONCLUSIONS

Adding an indirect AHR test to clinical monitoring of childhood asthma reduced the number of mild exacerbations, with similar current clinical control and final ICS dose as in the symptom-monitored group. The hypertonic saline test appears to be a simple, cheap, and safe tool for monitoring the treatment of mild-to-moderate asthma in children.

Bronchial hyperresponsiveness is common in Hanoi, Vietnam: Asthma probably underdiagnosed

BACKGROUND

Bronchial hyperresponsiveness (BHR) is a key pathophysiological feature of asthma. Methacholine challenge test (MCT) is a common bronchoprovocation test useful for confirming a diagnosis of asthma. Studies of BHR in the general population of Asian countries are rare.

AIM

To estimate prevalence and determinants of BHR in Hanoi, Vietnam, and to study the association between BHR and symptoms common in asthma and previously diagnosed asthma.

METHODS

1500 out of 5872 randomly selected adults in urban and rural Hanoi, who had participated in a questionnaire survey (83% participated), were randomly selected and invited to clinical examinations. Totally 684 subjects (46%) participated. MCT was performed in 366 subjects. BHR was defined as a FEV₁-decrease of ≥20% from baseline following methacholine inhalations (PC₂₀). Cut offs used in the analyses were PC₂₀ ≤ 1 mg/ml, ≤2 mg/ml and ≤8 mg/ml.

RESULTS

The prevalence of BHR was 16.4% at doses ≤8 mg/ml, while 9.6% reacted on doses ≤2 mg/ml. PC₂₀ ≤ 2 mg/ml was associated with FEV₁ <80% of predicted. PC₂₀ ≤ 2 mg/ml, but not PC₂₀ ≤ 8 mg/ml, was associated with multi-sensitization to airborne allergens. BHR defined as PC₂₀ ≤ 8 mg/ml was associated with age >45y. The combination of asthmatic wheeze (wheezing with breathlessness apart from colds) and BHR, irrespectively of magnitude of BHR, was more common than the combination of BHR with previously diagnosed asthma.

CONCLUSIONS

The results indicate BHR to be more common in Hanoi than previously found in south-east Asia. Although the prevalence of physician diagnosed asthma has increased in Vietnam, our results indicate that asthma still may be underdiagnosed in Vietnam.

Concordance for changes in allergic asthma domain variables after short-term corticosteroid therapy

Background

Asthma is a complex syndrome with multiple domains including symptoms, lung function, asthma control, and airway inflammation. A study of Fenom PRO™, a novel monitor for exhaled nitric oxide (FeNO), provided an opportunity to look at concordance/discordance (C/D) for changes in multiple asthma domains over a 2-week period after corticosteroid therapy.

Methods

Non-steroid-treated adults and children with uncontrolled asthma had asthma domain measures, (FeNO), forced expired volume in 1 s (FEV₁), the 6-item Asthma Control Questionnaire scores (ACQ6), and daily asthma symptoms, assessed before and after a 2-week course of corticosteroids. Asthma symptoms were assessed using a custom novel twice-daily symptom scale (ASX). C/D bidirectional changes in all domains were calculated around both the zero point, and around the minimal important difference (MID) in relevant subjects.

Results

There was a highly significant fall in mean FeNO of 51.7% over 2 weeks (p < 0.0001) accompanied by significant improvements in mean FEV₁, ACQ6 and ASX scores. However, C/D between individual domains varied considerably between subjects. The C/D between parameters for any change around zero for the combined adults and pediatric population was best for FeNO and ACQ6, 79.3/20.7% while FEV₁ was more discordant than other parameters in general. When considering changes around the minimal important difference (MID) in a subset, the level of concordance increased in general, with FeNO and ACQ6 demonstrating a C/D of 93.5/6.6%.

Conclusion

This data demonstrates that the concordance between changes in the asthma domains is often substantially less than 100%. Reasons for this may include different time courses for change of the separate domains, the degree of abnormality for each domain at baseline, as well as intrinsic limitations of each parameter.

Value of bronchial reversibility to salbutamol, exhaled nitric oxide and responsiveness to methacholine to corroborate the diagnosis of asthma in children

INTRODUCTION AND OBJECTIVES

Functional and inflammatory measures have been recommended to corroborate asthma diagnosis in schoolchildren, but the evidence in this regard is conflicting. We aimed to determine, in real-life clinical situation, the value of spirometry, spirometric bronchial reversibility to salbutamol (BDR), bronchial responsiveness to methacholine (MCT) and fractional exhaled nitric oxide (FENO), to corroborate the diagnosis of asthma in children on regular inhaled corticosteroids (ICS) referred from primary care.

METHODS

One hundred and seventy-seven schoolchildren with mild-moderate persistent asthma, on treatment with regular ICS, participated in the study. Abnormal tests were defined as FENO ≥ 27 ppb, BDR (FEV1 ≥ 12%) and methacholine PC20 ≤ 4 mg/mL.

RESULTS

The proportions of positive BDR, FENO and MCT, were 16.4%, 33.3%, and 87.0%, respectively. MCT was associated with FENO (p < 0.03) and BDR (p = 0.001); FENO was associated with BDR (p = 0.045), family history of asthma (p = 0.003) and use of asthma medication in the first two years of life (p = 0.004). BDR was significantly related with passive tobacco exposure (p = 0.003).

CONCLUSIONS

Spirometry, BDR and BDR had a poor performance for corroborating diagnosis in our asthmatic children on ICS treatment; on the contrary, MCT was positive in most of them, which agrees with previous reports. Although asthma tests are useful to corroborate asthma when positive, clinical diagnosis remains the best current approach for asthma diagnosis, at least while better objective and feasible measurements at the daily practice are available. At present, these tests may have a better role for assessing the management and progression of the condition.

Disparate diagnostic accuracy of lung function tests as predictors of poor asthma control in children

Rationale: In practice, asthma control is assessed according to symptom burden and office spirometry. However, spirometry poorly tests peripheral lung function, which may be abnormal in asthma. Impluse oscillometry (IOS) and multiple-breath washout (MBW) are novel methods which measure reactance (X5) and ventilation heterogeneity (VH) in the peripheral lung, but how well these tests reflect asthma control is poorly understood. Objective: To compare the diagnostic accuracy of tests of large airways caliber (FEV₁, FEV₁/FVC, R20), peripheral zone properties (X5, VH), and airways inflammation (FeNO) as predictors of poor control in asthmatic children (44 poorly controlled/10 controlled). Methods: 54 children enriched in severe asthma completed a symptom-based control scale (ACT/cACT) and lung function tests after overnight bronchodilator withhold. The accuracy of each variable to predict poor control was ranked by area under the receiver operating characteristic (ROC) curve, sensitivity and specificity. Results: Among measures of large airways caliber, the FEV₁% had the highest ROC curve area, with low sensitivity but perfect specificity. Among measures of peripheral lung function, X5 and VH in the conducting zone had fair curve areas with higher sensitivity but lower specificity compared to the FEV₁%. VH in the acinar zone and FeNO both had poor accuracy. Conclusion: Tests of large airway and peripheral zone lung function performed disparately as predictors of poor control in a sample of children enriched in severe asthma. Further studies in a larger sample with more diverse phenotypic features are necessary to validate this preliminary conclusion.

Predictive and Diagnostic Value of Fractional Exhaled Nitric Oxide in Patients with Chronic Rhinosinusitis

Background

Fractional exhaled nitric oxide (FeNO) participates in the local defense of the upper respiratory tract. Abnormal FeNO level is directly related to the occurrence of nasal diseases. However, the clinical value of FeNO in the upper airway is limited, which greatly impedes the diagnosis and treatment of nasal diseases. Here, we assessed the level of FeNO and evaluated the diagnostic accuracy of FeNO for chronic rhinosinusitis.

Material/Methods

We enrolled 35 patients with confirmed nasal inflammation and 30 healthy subjects from December 2016 and June 2017. The FeNO level was measured using a fractional exhaled nitric oxide detector. The level of FeNO in patients with different clinicopathological factors was compared. The diagnostic potential of FeNO for chronic rhinosinusitis was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

FeNO level was significantly lower in patients with nasal inflammation than in healthy subjects (P<0.05). For nasal inflammation diagnosis, FeNO had the highest area under the curve (AUC) at 0.760, with a sensitivity of 93.30% and a specificity of 68.60%. FeNO level was significantly downregulated in chronic rhinosinusitis patients relative to chronic rhinitis patients (P<0.05). FeNO had a good ability to discriminate between chronic rhinosinusitis patients and chronic rhinitis patients, with higher AUC, sensitivity, and specificity of 0.760, 93.30%, and 68.60%, respectively. However, FeNO levels were not significantly different between different histological types of chronic rhinosinusitis (P>0.05).

Conclusions

Our results show that FeNO is a useful marker for discriminating chronic rhinosinusitis, and has potential to provide valuable information in the early diagnosis of chronic rhinosinusitis.

Prospective observational cohort study of symptom control prediction in paediatric asthma by using the Royal College of Physicians three questions

The Royal College of Physicians three questions (RCP3Q) is widely used for assessing asthma control within primary care in the UK, despite limited evidence in children. This study compared the RCP3Q as a tool for assessing asthma control in children (5–16 years) against the validated Asthma Control Test (ACT), Childhood Asthma Control Test (C-ACT), and Mini-Paediatric Quality of Life Questionnaire (MiniPAQLQ). We conducted a prospective observational cohort study involving children from eight primary care practices in Leicestershire. Children with doctor diagnosed asthma, or receiving regular asthma medication, were invited to participate. A total of 319 participants completed the MiniPAQLQ and the C-ACT/ACT questionnaires, before RCP3Q responses were collected as part of their routine asthma review conducted immediately afterwards. RCP3Q sensitivity for detecting uncontrolled asthma ranged from 43–60% and specificity from 80–82%. Using an RCP3Q score ≥2 to predict uncontrolled asthma and an RCP3Q score of zero to predict well-controlled asthma resulted in 10% of participants misclassified as uncontrolled and 8% as well-controlled, respectively. Using an RCP3Q threshold score of ≥1 resulted in 25% of participants being misclassified as uncontrolled. Our data suggests limited utility of the RCP3Q to assess asthma control in children. Alternative indicators of asthma control, such as the validated Asthma Control Test and the Children’s Asthma Control Test should be considered instead.

Validated asthma control tests should be used to assess children rather than the ‘three questions’ survey recently developed by the Royal College of Physicians. The UK-based organisation developed the RCP3Q as a practical, rapid way of assessing asthma control in primary care. However, the RCP3Q was never comprehensively trialed for use with children. Erol Gaillard and co-workers at the University of Leicester compared the RCP3Q with three validated tests and questionnaires to determine its efficacy in assessing patients aged 5 to 16. 319 child patients completed the validated tests and their RCP3Q responses were collected immediately afterwards on the same day. In comparison with validated tests, the RCP3Q varied in its accuracy depending on the threshold scores selected. A threshold score of 1 resulted in 25 per cent of participants being misclassified with uncontrolled asthma.

Asthma control in preschool children with small airway function as measured by IOS and fractional exhaled nitric oxide

OBJECTIVE

This study investigated the accuracy of impulse oscillometry (IOS) combined with fractional exhaled nitric oxide (FeNO) to assess asthma control among preschool children.

METHODS

A total of 79 preschool children(3-6 year old) with asthma and 25 healthy preschool children who visited a paediatrician were enrolled in this study. All of the children were tested for allergens, respiratory system resistance (at 5 and 20 Hz [R5, R20]), respiratory system reactance (at 5 Hz [X5]), the resonant frequency of reactance (Fres), and the area under the reactance curve (between 5 Hz and Fres (reactance area [AX]) using IOS and FeNO. A paediatric respiratory specialist who was unaware of the IOS and FeNO results assigned children with asthma to either the asthma-controlled group (n = 27) or the asthma-uncontrolled group (n = 52) based on the Global Initiative for Asthma (GINA) criteria. A healthy control group (n = 25) was also included. The relationships between the FeNO and IOS values as well as the asthma control of the three groups were analysed, and the areas under the curve (AUCs) were calculated for each measure.

RESULTS

(1) During the controlled group, means±standard deviations of AX, R5-20, R5, X5 and FeNO were 26.15 ± 7.534, 3.52 ± 1.311,9.97 ± 1.576,-3.85 ± 0.572,-3.85 ± 0.572. During the uncontrolled group, means±standard deviations of AX,R5-20,R5,X5 and FeNO were 38.34 ± 13.563,5.36 ± 1.545,11.41 ± 2.029,-5.07 ± 1.554,36.40 ± 21.07. Among preschool children, significant differences were observed between the controlled and uncontrolled group with regard to the small airway functional parameters (AX, R5-20, R5, and X5) and FeNO(P <0.05).(2) A receiver operating characteristic (ROC) analysis showed that the AUCs were 0.786 for FeNO alone, 0.751 for X5 alone, and 0.866 for X5 combined with FeNO (cut-off value: 27 ppb).

CONCLUSION

FeNO combined with the small airway function parameter X5 accurately assessed asthma control among preschool children.

Pediatric pulmonology year in review 2016: Part 2

Pediatric Pulmonology continues to publish research and clinical topics related to the entire range of children's respiratory disorders. As we have done annually in recent years, we here summarize some of the past year's publications in our major topic areas, as well as selected literature in these areas from other core journals relevant to our discipline. This review (Part 2) covers selected articles on neonatology, asthma, physiology and lung function testing, and infectious diseases.