BACKGROUND: Characterizing associations between the upper and lower airways is important for asthma management. OBJECTIVES: This study aimed to assess the determinants of incomplete asthma control in patients with allergic rhinitis (AR) and asthma. METHODS: Multiple factors including age, sex, atopy, smoking history, medication use, Asthma Control Questionnaire (ACQ) score, FEV1, fraction of exhaled nitric oxide (F-ENO), and rhinitis questionnaire score were examined. AR was defined by rhinitis symptoms and the sensitization to inhaled allergens. ACQ was used to dichotomize the subjects into the incompletely controlled group (ACQ score >= 0.75) and the well-controlled group. The factors that contribute to incomplete asthma control were assessed by a multivariate analysis. RESULTS: A total of 260 patients with AR and asthma were enrolled and 108 patients (42%) were classified as incomplete asthma control. The incompletely controlled group was older (P<.05), and had more airflow limitation, more airway inflammation, and more severe rhinitis symptoms (all P<.001). In contrast, the well-controlled group was more likely to be taking nasal corticosteroids (NCSs) (P<.01). In a multivariate model adjusted by age, asthma treatment, airflow limitation, and FENO, persistence and severity of rhinitis (odds ratio [OR], 2.57; 95% CI, 1.41-4.70, and OR, 2.00; 95% CI, 1.10-3.65) and nonuse of NCSs (OR, 3.83; 95% CI, 1.50-9.81) were independently associated with incomplete asthma control. CONCLUSIONS: The persistence and severity of AR and the use of NCSs were associated with the level of asthma control in patients with AR and asthma. Further studies are required to determine whether appropriate treatment of rhinitis would improve asthma control. (C) 2016 American Academy of Allergy, Asthma & Immunology