ObjectiveTo identify factors affecting the efficacy of steroid-eluting sinus stents implanted after endoscopic sinus surgery (ESS) in patients with chronic rhinosinusitis with nasal polyps (CRSwNP).MethodsWe performed a post-hoc analysis of a randomized self-controlled clinical trial on post-operative implantation of bioabsorbable steroid-eluting stents in patients with CRSwNP. Univariate logistic regression analysis was conducted to identify which of the following factors affect the response to post-operative stent implantation: sex, serum eosinophil levels, history of prior surgery, endoscopic scores, and comorbid conditions (asthma and allergic rhinitis). The primary outcome was the rate of post-operative intervention on day 30, and the secondary outcome was the rate of polypoid tissue formation (grades 2-3) on days 14, 30, and 90.ResultsA total of 151 patients with CRSwNP were included in the post-hoc analysis. Asthma was identified as the only risk factor for a poor response to steroid-eluting sinus stents on post-operative day 30, with an odds ratio of 23.71 (95% CI, 2.81, 200.16; P=0.004) for the need for post-operative intervention and 19 (95% CI, 2.20, 164.16; P=0.003) for moderate-to-severe polypoid tissue formation. In addition, the asthmatic group showed higher rates of post-operative intervention and polypoid tissue formation than the non-asthmatic group on post-operative day 30. Blood eosinophil levels were not identified as a risk factor for poor outcomes after stent implantation.ConclusionComorbid asthma, but not blood eosinophil level, impairs the efficacy of steroid-eluting sinus stents in the short term after ESS in patients with CRSwNP.