Allergic Rhinitis Amplifies Asthma Risk in Patients With Chronic Rhinosinusitis: A Large-Scale Retrospective Cohort Analysis.

BACKGROUND

Chronic rhinosinusitis (CRS) and allergic rhinitis (AR) are two highly prevalent airway diseases in the United States. While the coexistence of CRS and asthma is well recognized, less is known about the development of new-onset asthma in CRS, particularly in the context of comorbid AR. This study assessed the impact of CRS and AR on incident asthma using a large electronic health record (EHR) database.

METHODS

We conducted a retrospective cohort study using the TriNetX US Collaborative Network, a federated EHR platform encompassing over 100 million patients. Adults ≥ 18 years between January 2009 and December 2019 with CRS were compared to controls without CRS. A second analysis compared patients with CRS and concurrent AR to those with CRS alone. Supplemental analyses substituted chronic rhinosinusitis with nasal polyps (CRSwNP) for CRS. Propensity score matching balanced cohorts on demographics and comorbidities. Primary outcomes were new-onset asthma and asthma exacerbations, assessed at 1, 2, and 5 years.

RESULTS

After matching, pre-existing CRS was associated with higher risk of new-onset asthma (adjusted relative risk [aRR] = 1.42, 95% CI 1.36-1.48) and exacerbations (aRR = 1.87, 95% CI 1.75-2.00) at 1 year versus CRS controls, with similar trends at 2 and 5 years. Coexisting AR further amplified risk: patients with CRS + AR had increased asthma incidence relative to CRS alone at 1 year (aRR = 1.69, 95% CI 1.65-1.73), 2 years (aRR = 1.65, 95% CI 1.62-1.68), and 5 years (aRR = 1.58, 95% CI 1.56-1.60), with more than doubled exacerbation risk across all time points. Directionally similar findings were observed in CRSwNP analyses.

CONCLUSIONS

CRS is associated with increased risk of incident asthma and subsequent exacerbations, and coexisting AR identifies a higher-risk phenotype within CRS. These findings highlight the need for phenotype-informed studies to determine whether targeted upper-airway management can mitigate downstream asthma burden.