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Relationship between exhaled nitric oxide levels and compliance with inhaled corticosteroids in asthmatic children
Maria Katsara1, Deidrie Donnelly, Shaique Iqbal
1Paediatric Respiratory Unit, Sheffield Children's Hospital, Western Bank, Sheffield S10 2TH, UK.
Insights
Exhaled nitric oxide (eNO) levels in children with asthma may indicate poor adherence to inhaled corticosteroids (ICSs). However, factors like disease activity and inhaler technique also influence eNO, requiring further research for precise clinical application.
Area of Science:
- Pediatric Pulmonology
- Allergy and Immunology
- Biomarkers in Respiratory Disease
Background:
- Elevated exhaled nitric oxide (eNO) is characteristic of asthma and decreases with steroid treatment.
- The potential of eNO measurements to identify non-adherence to asthma treatment regimens was explored.
Purpose of the Study:
- To investigate if exhaled nitric oxide (eNO) levels can identify children with asthma who are not adhering to their inhaled corticosteroid (ICS) treatment.
- To assess the correlation between treatment compliance and eNO levels in pediatric asthma patients.
Main Methods:
- Twenty children with asthma were recruited for monthly eNO measurements over four months.
- A data logger on metered dose inhalers objectively monitored adherence to inhaled corticosteroids (ICSs).
- Statistical analysis assessed the correlation between daily/dosing compliance and eNO levels.
Main Results:
- A weak, non-significant correlation was found between eNO levels and both daily (r = 0.055) and dose compliance (r = 0.153).
- eNO values below 12 ppb were observed across a wide range of compliance rates (3-97%).
- Approximately 80% of eNO values above 12 ppb were associated with less than 50% compliance in the preceding month.
Conclusions:
- Elevated eNO in asthmatic children on ICSs may suggest poor adherence, but this requires careful consideration of confounding factors.
- Disease activity, viral exacerbations, pollen exposure, and inhaler technique can influence eNO levels, complicating direct correlation with compliance.
- While eNO shows promise as a management tool for pediatric asthma, further research is needed to clarify its specific role and refine interpretation.
Abstract:
Levels of exhaled nitric oxide (eNO) are elevated in subjects with asthma and fall in response to oral or inhaled steroids. This study explored the possibility the measurement of eNO levels could be used to identify subjects who were not adhering to their treatment regimen. Twenty children with asthma attending the respiratory clinic were recruited. Each attended on four occasions 1 month apart when eNO levels were measured. A data logger attached to a pressurised metered dose inhaler was used to objectively monitor use of inhaled corticosteroids (ICSs). The correlation between day and dose compliance with eNO was assessed. The data demonstrated a weak but non-significant correlation between eNO and both day (r = 0.055, P = 0.67) and dose (r = 0.153, P = 0.23). A recorded value of eNO less than 12 was associated with day compliance rates of 3-97%. Of the 19 recorded eNO values greater than 12 ppb almost 80% were from subjects with a day compliance of less than 50% during the preceding month. Of the four values greater than 12 ppb and day compliance > 60% one subject had a poor inhaler technique, one had a mild viral exacerbation and one appeared to be associated with increase pollen exposure. The measurement of eNO may prove to be a useful tool in helping to manage children with asthma but further work is required to define its precise role. Elevated eNO levels in asthmatic children taking ICSs are likely to reflect poor compliance but confounding factors such as disease activity and inhaler technique need to be carefully considered.
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