Fractional exhaled nitric oxide levels as a predictor of long-term prognoses in patients with mild asthma.

Abstract

There is a growing belief that patients with bronchial asthma (BA) should be provided an individualized and optimized treatment plan. We aimed to clarify the predictors of long-term prognoses in patients with mild BA. We conducted a retrospective study of consecutive patients who were newly diagnosed with mild BA at Iwate Medical University from 2011 to 2013, focusing on achievement of full asthma control based on the Asthma Control Test as an indicator of prognosis. Predictors were identified on the basis of a chart review. Among 71 patients with mild BA, 37 patients completed regular clinic visits for 1 year. Nineteen (51.4%) of these patients achieved full asthma control. Current smoking and the fractional exhaled nitric oxide (FeNO) level at the first patient visit were identified by multivariate logistic regression as possible predictors of the discontinuation of clinic visits and achievement of full asthma control, respectively. Low FeNO levels at the first clinic visit yielded a receiver operating characteristic-area under the curve of 0.860 (95% confidence interval [CI]=0.774-0.975) for the achievement of full asthma control. Using an FeNO cut-off level of 34 parts per billion yielded a sensitivity of 76.5% (95% CI=59.5-88.2%) and specificity of 73.7% (95% CI=58.5-84.2%). Our preliminary results suggested that patients with newly diagnosed mild BA who display higher FeNO levels at their first clinic visits should be appropriately educated during early visits to receive optimal treatment and complete regular clinic visits.