Diagnostic Accuracy of Exhaled Nitric Oxide for Detection of Chronic Cough and the Responsiveness to Inhaled Corticosteroid: A Meta-analysis

Abstract

SESSION TITLE: Cough SESSION TYPE: Original Investigation Poster PRESENTED ON: Saturday, April 16, 2016 at 11:45 AM - 12:45 PM PURPOSE: Eosinophilic airway inflammation (EAI) related chronic cough accounts for a large majority of the causes. Measurement of fractional exhaled nitric oxide (FeNO) is a simple, noninvasive tool for assessing eosinophilic airway inflammation, but the estimates of accuracy in detection chronic cough related to EAI varied. And the the predictive response to inhaled corticosteroid (ICS) remains controversial. METHODS: We did a systematic review and searched Pubmed, Web of Science, and Cochrane library for studies evaluating the diagnostic accuracy of FeNO in cough etiology or treatment response to ICS. Unpublished studies were obtained through contacting the authors. After data extraction by two independent reviewers, the sensitivity, specificity, and other measures of accuracy were pooled using random-effects models. Summary receiver operating characteristic curves were used to summarize overall test performance. RESULTS: We included 12 studies: 7 in etiologic studies and four predicted the responsiveness to ICS in chronic cough. The summary estimates for FeNO in the diagnosis of asthmatic cough in the studies included were as follows: sensitivity, 0.82 (95% confidence interval [CI], 0.77 to 0.86); specificity, 0.84 (95% CI, 0.81 to 0.86); positive likelihood ratio, 4.3 (95% CI, 4.10 to 5.91); negative likelihood ratio, 0.25 (95% CI, 0.16 to 0.38); and diagnostic odds ratio, 21.82 (95% CI, 12.21 to 39). The summary estimates for FeNO in the diagnosis of non-asthmatic eosinophilic bronchitis (NAEB) were as follows: sensitivity, 0.71 (95% CI, 0.61 to 0.79); specificity, 0.76 (95% CI, 0.70 to 0.81); positive likelihood ratio, 3,30 (95% CI, 2.02 to 5.42); negative likelihood ratio, 0.39 (95% CI, 0.28 to 0.52); and diagnostic odds ratio, 10.71 (95% CI, 4.17 to 27.52). The summary area under the receiver operator curve (AUC) for detection of asthmatics cough and NAEB were 0.90 (0.8874-0.9114) and 0.81 (0.7838-0.8430), respectively. Pooled estimate of FeNO in classifying ICS responsive chronic cough were as follows: sensitivity, 0.73 (95% CI, 0.64 to 0.80), specificity, 0.81 (95% CI, 0.74 to 0.88) and the summary AUC 0.8856 (0.8101-0.9611). CONCLUSIONS: FeNO is useful in the evaluation of patients with EAI related chronic cough, especially asthmatic cough. Also, an enhanced FeNO level has moderate value in predicting the responsiveness to ICS in chronic cough patients. CLINICAL IMPLICATIONS: Fractional exhaled nitric oxide test can be applied in diagnostic algorithm of chronic cough in clinic. DISCLOSURE: The following authors have nothing to disclose: Zhangfu Fang, Fang Yi, Mei Jiang, Haojun Xie, Fagui Chen, KeFang Lai No Product/Research Disclosure Information