Exhaled and nasal nitric oxide in chronic rhinosinusitis patients with nasal polyps in primary care.

Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common inflammatory disorder associated with lower airway disease. However, only few studies of CRSwNP from outside secondary/tertiary care centres have been published. We recently reported an asthma frequency of 44% and 65% in primary and secondary care patients respectively. Therefore, we hypothesise that inflammation of the lower airways could be present in all CRSwNP patients, even without asthma. Here, we assessed the degree of lower and upper airway inflammation using exhaled and nasal nitric oxide (NO) in primary care CRSwNP patients with and without asthma.

Methods: Fifty-seven patients who met the EPOS criteria for CRSwNP were prospectively recruited from primary care ear, nose and throat clinics. Nasal endoscopy was performed by an ear, nose and throat specialist upon enrolment. Additionally, 30 healthy controls were enrolled. Expiratory and nasal NO measurements and thorough pulmonary evaluation were performed. Pulmonary disease was diagnosed by a respiratory physician.

Results: Fifty-nine percent of CRSwNP patients with asthma showed elevated expiratory NO; the same was seen in 29% of non-asthmatic CRSwNP patients. Compared with controls, a high level of exhaled NO was significantly more prevalent in CRSwNP irrespective of asthma-status. Nasal NO was significantly lower in patients with CRSwNP compared with controls.

Conclusion: Subclinical eosinophilic lower airway inflammation is common in CRSwNP in the primary sector, even in the absence of asthma.