BackgroundThe long-term impact of chronic rhinosinusitis (CRS) with or without allergic rhinitis (AR) on asthma is poorly documented. This study analyzed potential associations of ongoing CRS and AR on asthma. MethodsUsing the MarketScan claims database, patients with CRS and endoscopic sinus surgery (ESS) in 2010 were identified. The date of first sinusitis was determined for all. Patients with asthma at time of first sinusitis diagnosis were excluded. The remaining patients were grouped based on duration of sinusitis, from first diagnosis to surgerygroup 1: 1 to <2 years (n = 181); group 2: 2 to <3 years (n = 195); group 3: 3 to <4 years (n = 292); and group 4: 4 to <5 years (n = 536). Yearly incidence and prevalence of newly diagnosed asthmatics was analyzed for all groups. A secondary analysis evaluated the association between AR and asthma. ResultsPreoperatively, yearly incidence of patients with new asthma diagnoses averaged 4.48% (95% confidence interval [CI], 3.93% to 5.11%) and was significantly greater for patients with AR (5.93%; 95% CI, 4.56% to 7.66%) vs non-AR (4.15%; 95% CI, 3.56% to 4.82%); p = 0.03. Postoperatively, yearly incidence of asthma was 0.42% (95% CI, 0.18% to 0.88%). No patient had asthma at time of first diagnosis; however, by time of surgery, 9.4%, 12.8%, 18.2%, and 22.40% of patients had been diagnosed with asthma, in groups 1 through 4, respectively. ConclusionAR was a significant risk factor for asthma in patients with CRS. Medically recalcitrant CRS was associated with high incidence rates of asthma, which declined post-operatively. Patients operated earlier in the disease continuum were therefore at decreased risk of developing asthma.