Is a positive nasal lysine-aspirin challenge test associated with a more severe phenotype of chronic rhinosinusitis and asthma?

Background: Current guidelines recommend a greater use of aspirin challenge testing in the diagnosis of aspirin-intolerant rhinosinusitis and asthma, a disorder with high burden of illness and resistance to treatment. The indications for these tests and their clinical significance remain unclear. This study was designed to characterize the phenotype of patients with chronic rhinosinusitis with nasal polyposis (CRSwNP) with or without asthma undergoing a nasal lysine-aspirin (L-ASA) challenge to evaluate which factors strongly predict a positive test.

Methods: Seveny-five patients with CRSwNP underwent nasal challenge with 16 mg (total) of L-ASA after 30 minutes of acclimatization and diluent challenge. A positive challenge was defined as a 25% drop in total nasal volume measured by acoustic rhinometry.

Results: Twenty-three (31%) participants gave a history of aspirin intolerance and 38 (51%) had a positive nasal L-ASA challenge. Upper airway measures (CT scan score, olfaction, polyp grading, peak nasal inspiratory flow, nasal symptoms, etc.) and lower airway measures (methacholine provocative concentration required to produce a 20% drop in forced expiratory volume in 1 second, effective special airway resistance, and spirometry) were not significantly worse in patients with a positive aspirin challenge. Test sensitivity was 48%, specificity was 52%, positive predictive value was 29%, and negative predictive value was 68%. A regression analysis identified forced expiratory flow at 25-75% (FEF25-75), history of aspirin intolerance, and duration of rhinosinusitis as significant predictors of a positive aspirin challenge.

Conclusion: A positive response to nasal L-ASA challenge is not associated with a more severe phenotype of CRSwNP with or without asthma. A history of aspirin intolerance, duration of rhinosinusitis, and FEF25-75 predict a greater response to aspirin. (Am J Rhinol Allergy 26, e89-e93, 2012; doi: 10.2500/ajra.2012.26.3767)