P13 Exhaled nitric oxide and blood eosinophil count in predicting sputum inflammatory type in a heterogeneous airways disease population

Objective: This study aimed to explore the usefulness of the peripheral blood eosinophil count (PBEC) in assessing the level of fractional exhaled nitric oxide (FeNO) and predicting bronchodilation test results. Methods: We retrospectively analyzed the data of 384 outpatients who underwent FeNO measurement at our Department of Respiratory and Critical Care Medicine from March to June 2019. The FeNO level was compared among different PBECs to explore the association among them. Furthermore, the sensitivity and specificity of PBECs in predicting bronchodilation test results were assessed by using receiver operating characteristic (ROC) curve analysis. Results: There was a moderate correlation between PBECs and FeNO levels (r = 0.414; p < 0.05). In the subjects with PBECs ≥ 0.3 × 109/L, the median FeNO level was 39 ppb (interquartile range, 22.5‐65.5 ppb), significantly higher than in the subjects with PBECs < 0.3 × 109/L. The area under the ROC curve was 0.707 (p < 0.05). The maximum Youden index (0.348) was at PBECs = 0.205 × 109/L, which achieved sensitivity and specificity of 63% and 71.8%, respectively. Conclusion: PBECs ≥ 0.3 × 109/L can predict a positive bronchodilation test result and a high FeNO level, with a probability of 50% in the subjects with chronic cough and shortness of breath; in the absence of corresponding symptoms and a low PBEC, the predictive value was small. For hospitals not able to conduct FeNO measurements, for outpatients with poor economic conditions, and for patients with confirmed or suspected novel coronavirus disease 2019, the PBEC, in conjunction with a patient's clinical symptoms, can improve the diagnostic accuracy of allergic asthma and assessment of airway inflammation while reducing the risk of infection.

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Predictors of Loss of Asthma Control Induced by Corticosteroid Withdrawal

Canadian Respiratory Journal ◽

10.1155/2006/189127 ◽

2006 ◽

Vol 13 (3) ◽

pp. 129-133 ◽

Cited By ~ 29

Author(s):

Jose Belda ◽

Krishnan Parameswaran ◽

Catherine Lemière ◽

Dennis Kamada ◽

Paul M O'Byrne ◽

...

Keyword(s):

Nitric Oxide ◽

Asthma Control ◽

Eosinophil Count ◽

Inhaled Corticosteroids ◽

Forced Expiratory Volume ◽

Exhaled Nitric Oxide ◽

Baseline Risk ◽

Blood Eosinophil ◽

Inhaled Corticosteroid ◽

Sputum Eosinophil

BACKGROUND: Asthma guidelines recommend reducing the dose of inhaled corticosteroids after establishing control.OBJECTIVE: To identify predictors of loss of control and the kinetics of symptoms, and inflammatory and physiological measurements when inhaled corticosteroids are reduced in patients with stable asthma.PATIENTS AND METHODS: In a single-blind study, the daily dose of inhaled corticosteroid was reduced by one-half at intervals of 20±2 days in 17 adults with controlled asthma until loss of asthma control occurred or until the corticosteroid was replaced with placebo for 20 days. The patients recorded symptoms and peak expiratory flow each day, and forced expiratory volume in 1 s (FEV1), the provocative concentration of methacholine causing a 20% fall in FEV1(PC20), exhaled nitric oxide, and eosinophils in sputum and blood were measured every 10 days. A loss of asthma control was defined as a worsening of the symptoms score of at least 20%, and either a decrease in FEV1of at least 15% or a decrease in PC20of at least fourfold.RESULTS: Two patients had a respiratory infection and were withdrawn from the study. In eight patients, asthma became uncontrolled after a mean of 33 days (range 13 to 48 days). This was accurately reflected by a worsening of all parameters. The first parameter to change was the sputum eosinophil percentage (20 days before the loss of asthma control). Significant changes in exhaled nitric oxide, FEV1and methacholine PC20were observed only when the symptoms became uncontrolled. A high blood eosinophil count at baseline (risk ratio of 2.5, 95% CI 1.0 to 6.5) and an increase in sputum eosinophil count after the reduction of corticosteroids were predictors of loss of asthma control.CONCLUSION: In patients whose asthma is controlled on inhaled corticosteroid, it is prudent not to reduce the dose further if the blood eosinophils are increased or if the sputum eosinophils increase by as little as 1% after the reduction of corticosteroids.

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