Fractional Exhaled Nitric Oxide for Diagnosing Eosinophilic Chronic Rhinosinusitis: A Systematic Review and Meta‐analysis

OBJECTIVE: The current gold standard for diagnosing eosinophilic chronic rhinosinusitis (ECRS) is tissue biopsy, but due to its invasive nature, there is a need for clinical diagnosis in outpatient settings or presurgical evaluations. DATA SOURCES: PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus up to July 2024. REVIEW METHODS: Compared the fractional exhaled nitric oxide (FeNO) levels between ECRS and non-ECRS patients. The risk of bias across studies was evaluated utilizing the ROBINS-I tool. RESULTS: Twelve studies comprising 1159 participants were included. The pooled mean difference in FeNO levels between ECRS and non-ECRS patients was 32.21 ppb (95% CI: [19.36, 45.06], P < .001). The diagnostic odds ratio for FeNO in identifying ECRS was 8.78 (95% CI: [5.70, 13.51], P < .001). CONCLUSION: FeNO levels are significantly elevated in ECRS patients compared to non-ECRS patients. The high diagnostic odds ratio suggests that FeNO has potential as a noninvasive diagnostic tool for ECRS.