Association of elevated fractional exhaled nitric oxide concentration and blood eosinophil count with severe asthma exacerbations

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.

Download Full-text

Saudi Arabian real-life experience with biologic therapy in severe asthma

Multidisciplinary Respiratory Medicine ◽

10.4081/mrm.2021.807 ◽

2021 ◽

Vol 16 ◽

Author(s):

Safwat Eldaboussi ◽

Ahmed Qabil ◽

Ahmed Lotfi ◽

Amgad Awad ◽

Eman Abdel Salam ◽

...

Keyword(s):

Observational Study ◽

Asthma Control ◽

Severe Asthma ◽

Eosinophil Count ◽

Biologic Therapy ◽

Blood Eosinophil ◽

Blood Eosinophil Count ◽

Asthma Exacerbations ◽

Percent Improvement

Background: Severe asthma (SA) is a common health problem associated with increased morbidity and mortality and high medical costs. Biological therapies have emerged in recent decades as promising treatment options for patients with high type 2 (T2) SA. This retrospective observational study from Saudi Arabia aimed to investigate the effects of additional biologics therapy on reducing oral corticosteroid (OCS) consumption, frequency of asthma exacerbations, improvement in lung function, and asthma control.Methods: This multicenter observational study enrolled a cohort of 97 patients from Mach 2019 to February 2021. Outcomes of anti-IgE, anti-IL5/IL5R, and anti-IL4R therapies in severe type 2 asthma were recorded and analyzed in terms of number of exacerbations (emergency visits or hospitalizations required), asthma symptoms, and use of oral corticosteroids, blood eosinophil count, asthma control according to GINA classification, and FEV1 before and during biologic therapy.Results: Ninety-seven patients were included in the analysis The mean age was 46.7±14.1 years, and 69.1% of them were female. The average duration of biological treatment was 16.4±6.8 months. At the time of data collection, the four biologic therapies reduced the exacerbation rate per year from 82/97 (84.5%) to 14/97 (14.4%) with a percent improvement of 83% from 2.9 per year in the year before biologic treatment to 1.6 per year (p<0.001). OCS was reduced from 75/97 (77.3%) to 10/97 (10.3%) for a percent improvement of 86.7%, and the average OCS dose decreased from 7.12 mg to 6.8 mg. Mean blood eosinophil count also decreased after biologic therapy from 750.5±498.5 to 188.0±122.4 cells/μl, most significant result achieved with benralizumab, and mean FEV1 improved from 59.0±12.9% to 76.0±10.2%, most significant result achieved with omalizumab. ll patients had uncontrolled asthma before biologics therapy, but asthma control improved by 91.8% after treatment.Conclusions: Biologic as add-on therapy for high T2 SA was found to reduce asthma exacerbations, systemic glucocorticoid doses, and SA symptoms.

Download Full-text