Study of nasal exhaled nitric oxide levels in diagnosis of allergic rhinitis in subjects with and without asthma

Sy Duong-Quy,1–3 Thuc Vu-Minh,4 Thong Hua-Huy,1 Tram Tang-Thi-Thao,3 Khiet Le-Quang,3 Dinh Tran-Thanh,3 Nhu Doan-Thi-Quynh,3 Nhat-Nam Le-Dong,5 Timothy J Craig,2 Anh-Tuan Dinh-Xuan1 1Department of Respiratory Physiology, Cochin Hospital, Paris Descartes University, Sorbonne Paris Cité, Paris, France; 2Department of Medicine, Penn State University, Hershey, PA, USA; 3Bio-Medical Research Center, Lam Dong Medical College, Dalat, 4Department of Immuno-Allergology, ENT National Institute, Hanoi, Vietnam; 5Department of Pulmonology, St Elisabeth Hospital, Namur, Belgium Background: The measure of fractional exhaled nitric oxide (FENO) in the airways is a useful tool to guide the diagnosis and titration of inhaled corticosteroids in patients with asthma. However, its role in diagnosis of allergic rhinitis (AR), especially in subjects with asthma, is not well established. Objective: To study the cutoff of nasal FENO in the diagnosis of subjects with AR and AR-asthma compared to age-matched subjects without AR or asthma and its correlations with the clinical and functional characteristics. Methods: The study was cross sectional and descriptive. Subjects were grouped into control subjects, AR, and AR-asthma, based on the inclusion criteria. Exhaled NO (nasal FENO, bronchial FENO, and alveolar concentration of NO) was measured by multiple flow electroluminescence device. Results: Six hundred twenty-eight subjects were included: 217 control subjects (children: n=98, 10±4 years; adults: n=119, 50±16 years), 168 subjects with AR (children: n=54, 10±3 years; adults: n=114, 49±15 years), and 243 subjects with AR-asthma (children: n=115, 10±3 years; adults: n=128, 51±14 years). Nasal peak inspiratory flow and peak expiratory flow were lower in subjects with AR and AR-asthma than in control subjects (P