Nasal nitric oxide as a marker of sinus mucosal health in patients with nasal polyposis

BackgroundReduced nasal nitric oxide (nNO) has been shown in patients with chronic rhinosinusitis (CRS) but its clinical significance remains uncertain. The objective of this study was to measure nNO changes in patients undergoing endoscopic sinus surgery (ESS) for CRS and to explore its relationship to clinical measures of sinus mucosal health postoperatively. MethodsThis was a prospective study of CRS patients undergoing ESS. Patients had the following measurements at baseline and at 1 and 6 months post-ESS: nNO levels, Lund-Kennedy Endoscopy Score (LKES), and 22-item Sino-Nasal Outcome Test (SNOT-22) score. Statistical analysis was performed using GraphPad Prism 6. ResultsThirty-nine patients were enrolled, of these 84.6% had CRS with nasal polyps. Baseline Lund-Mackay computed tomography (CT) score was 16.9 5.1. There was a statistically significant increase in nNO levels from baseline to 1 month and 6 months postoperatively (p < 0.0001). The SNOT-22 and LKES followed a similar trend with a significant and sustained improvement at 1 month and 6 months post-ESS (p < 0.0001). Subgroup analysis revealed that changes in nNO were driven by the polyp cohort because nonpolyp patients had no significant changes in their nNO postoperatively. No correlation was found between nNO levels and SNOT-22. However, a significant negative correlation was found between nNO and LKES (p < 0.0001), suggesting healthier sinus mucosa was associated with higher nNO levels. ConclusionThis is the first study to show that nNO levels may be a marker of sinus mucosal health following ESS in patients with polyps. This has important implications for nNO in its potential etiologic role in mediating ongoing sinus inflammation.