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Background and Aims: There are some controversial reports that investigated the usefulness of exhaled nitric oxide (eNO) to predict the efficacy of inhaled corticosteroids (ICS) in chronic cough patients. Therefore, we retrospectively analysed the usefulness of eNO measurement with portable analyser to predict the requirement of ICS therapy in persistent cough (defined as lasting for 3 weeks or more) patients in Japan and investigated whether it might improve the management of persistent cough at primary care practice. Methods: We retrospectively reviewed the clinical records of adult patients who had been referred to our hospital for persistent cough from 1 June 2009 to 30 April 2011. Results: Forty-two patients had the requirement of ICS (group S) and 35 patients had no requirement of ICS (group N). Forty-three per cent of the patients who required ICS had not received ICS, and 29% of the patients who did not required ICS had received ICS. In the steroid-naive patients without current smoking, mean eNO level was significantly higher in group S [60.6 ± 14.1 perts per billion (ppb) vs 22.2 ± 2.3 ppb, P = 0.001] and the sensitivity and the specificity of eNO for predicting the requirement of ICS were 78.6% and 80.0%, respectively. The rate of the patients who received inappropriate treatment about ICS tended to be reduced from 41% to 21% if the eNO was used to predict the requirement of ICS with cut-off value of eNO 26.5 ppb (P = 0.118). Conclusion: Measurement of eNO could be one of the management tools for persistent cough at primary care practice. [ABSTRACT FROM AUTHOR]

Background: Exhaled nitric oxide (eNO) is a useful marker of eosinophilic airway inflammation in asthmatics. There have been no studies to show the relationship between eNO measured by offline methods and the degree of bronchial hyperresponsiveness in asthmatic patients treated with inhaled corticosteroids. Methods: The study population comprised asthmatics at our outpatient clinic. We measured eNO levels by two methods ("eNOs" was measured with a Sievers kit; and "eNOc" was measured with a kit from the Center for Environmental Information Science, Japan). We also used spirometry to test bronchial hyperresponsiveness to acetylcholine (PC20Ach). Results: We recruited 192 stable asthmatics. There was a significant relationship between eNOs and eNOc (r = 0.919, p < 0.001). LogPC20Ach levels were negatively correlated with eNOs or eNOc levels (eNOs, r = -0.31, p < 0.001; eNOc, r = -0.23, p = 0.0013). We classified the subjects into two groups based on eNOs levels ((A) the subjects with high eNOs levels (n = 92) and (B) the subjects with normal eNOs levels (n = 100)); logPC20Ach was significantly correlated with eNOs (r = -0.34, p = 0.001) or eNOc (r = -0.28, p = 0.0075) but not correlated with %FEV1 in (A), whereas logPC20Ach was not significantly correlated with eNO but significantly correlated with %FEV1 (r = 0.33, p = 0.002) in (B). Conclusions: Levels of eNOs and eNOc were correlated with the degree of bronchial hyperresponsiveness to acetylcholine in adult asthmatics treated with inhaled corticosteroids. Our findings suggest that offline monitoring of eNO will facilitate the management of bronchial asthma in patients treated with these drugs. [ABSTRACT FROM AUTHOR]