Diagnostic value of fractional exhaled nitric oxide in predicting cough variant asthma in children with chronic cough: a systematic review and meta-analysis

Objective·To evaluate the values of fractional exhaled nitric oxide (FeNO) for the diagnosis of cough variant asthma (CVA) in children with chronic cough by systematic review and meta-analysis.Methods·PubMed, Embase, Cochrane Library, Web of Science, China Biology Medicine Database (SinoMed), China National Knowledge Infrastructure (CNKI), and Wanfang Database were systematically searched for cohort studies and case-control studies to March 1, 2022. Two researchers independently screened the studies according to the inclusion and exclusion criteria, and the number of true positive, false positive, true negative, and false negative patients and the cut-off value of FeNO were extracted from the studies. Diagnostic accuracy studies tool version 2 (QUADAS-2) was used to evaluate the quality of the included literature in terms of risk bias and clinical applicability. Revman 5.4 was used to draw the quality evaluation chart. A meta-analysis was performed by the midas and spearman commands of Stata 17.0. Spearman co