Correlation of induced sputum eosinophil levels with clinical parameters in mild and moderate persistent asthma in children aged 7–18 years

ABSTRACT

Background: Treatment decisions in asthma are currently based on clinical assessment and spirometry. Sputum eosinophil, being a marker of airway inflammation, can serve as a tool for assessing severity and response to treatment in asthma patients. Objectives: To measure eosinophil percentage in induced sputum in children with asthma and correlate it with clinical asthma parameters. Methods: A prospective observational study was performed at tertiary care hospital on 91 children aged 7–18 years with newly diagnosed mild or moderate persistent asthma. Theinduced sputum eosinophil percentage was obtained at the time of enrollment and three months after treatment with inhaled budesonide. Patients were specifically evaluated for five clinical parameters of asthma, i.e., days of acute exacerbations, use of salbutamol as rescue medication, emergency visits, nighttime cough and days of school absence. Results: Sputum eosinophil percentage was high (3.1 ± 0.515%) at the time of enrollment which reduced significantly after three months of inhaled budesonide therapy [0.06 ± 0.164% (p < 0.0005)]. Children with moderate persistent asthma had significantly higher values of sputum eosinophil levels than children with mild persistent asthma at the time of enrollment (3.38 ± 0.64% vs. 2.99 ± 0.42%, p  =  0.001) but the difference was not significant after three months of inhaled steroid therapy (0.07 ± 0.18 vs. 0.04 ± 0.12, p  =  0.5104). A significant negative correlation was found between reduction in sputum eosinophil levels and improvement in FEV1 (r = −0.400, p = 0.0001). All the clinical asthma parameters also correlated significantly with the reduction in sputum eosinophil levels after three months of inhaled steroid therapy. Conclusion: Eosinophil levels in induced sputum correlate well with clinical asthma parameters and asthma severity in children. It is a simple, noninvasive and cheap method which can be used for the monitoring of asthma in a resource-limited setting.

KEYWORDS:

• Diagnosis
• FeV1
• monitoring
• pediatric asthma

Acknowledgements

The authors thank Dr. (Prof). T.P. Yadav, Head, Department of Pediatrics, Dr. Vivek Dewan, Prof., Department of Pediatrics and Dr. Gurdeep Buxi, Fr(PROF) Gurdeep Buxi former Head of unit Haematology, deptt. of Pathology, PGIMER, Dr. RML Hospital for their support during planning and execution of the study.

Ethical clearance

Ethical committee of PGIMER and RML Hospital, Delhi.

Financial disclosure

None.

Conflict of interest

None.