Outcomes using exhaled nitric oxide measurements as an adjunct to primary care asthma management

Abstract

Background:

Exhaled nitric oxide (F_ENO) measurements may help to highlight when inhaled corticosteroid (ICS) therapy should or should not be adjusted in asthma. This is often difficult to judge. Our aim was to evaluate a decision-support algorithm incorporating F_ENO measurements in a nurse-led asthma clinic.

Methods:

Asthma management was guided by an algorithm based on high (>45ppb), intermediate (30-45ppb), or low (<30ppb) F_ENO levels and asthma control status. This provided for one of eight possible treatment options, including diagnosis review and ICS dose adjustment.

Results:

Well controlled asthma increased from 41% at visit 1 to 68% at visit 5 (p=0.001). The mean fluticasone dose decreased from 312 mcg/day at visit 2 to 211mcg/day at visit 5 (p=0.022). There was a high level of protocol deviations (25%), often related to concerns about reducing the ICS dose. The % fall in F_ENO associated with a change in asthma status from poor control to good control was 35%.

Conclusion:

An F_ENO-based algorithm provided for a reduction in ICS doses without compromising asthma control. However, the results may have been influenced by the education and support which patients received. Reluctance to reduce ICS dose was an issue which may have influenced the overall results.

Trial registration:

Australian Clinical Trials Registry # 012605000354684