Predominance of Atopic Asthma in Patients with Severe or Difficult-to-Treat Asthma in the Tenor II Cohort

Rationale: The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens evaluated patients with severe or difficult-to-treat asthma (TENOR I). TENOR II assessed long-term outcomes in this cohort.  

Methods: TENOR II (n=341) was a prospective, multicenter observational study with a single follow-up assessment in 2014, more than a decade after TENOR I. Atopic asthma was defined as having ≥1 positive specific-IgE test (≥0.35kU/L). Clinical measures of atopic and non-atopic asthma patients were examined, as well as very poorly controlled (VPC) asthma based on National Heart, Lung, and Blood Institute asthma guidelines.

Results: Of 317 patients with a specific IgE measure, the majority (n=231; 72.9%) had atopic asthma; 86 (27.1%) had non-atopic asthma.  IgE geometric mean was 130.7 IU/mL and 14.1 IU/mL for atopic and non-atopic cohorts, respectively. The most common positive IgE tests for atopic patients were perennial aero-allergens: cat dander (59.7%), dog dander (53.7%) and Dermatophagoides farinadust mite (43.7%). Mean (SD) blood eosinophil count for atopic and non-atopic groups were 201/µL (143) and 198/µL (147), respectively.  Atopic and non-atopic patients were as likely to report any asthma exacerbation (defined as hospitalization/ER visit for exacerbations requiring corticosteroids) in the prior three months [24.7% (57/231) and 26.7% (23/86), respectively]. Over half (52.0%; 115/221) of atopic patients had persistent VPC asthma (VPC at TENOR I and TENOR II) versus 45.8% (38/83) of non-atopic patients.

Conclusions: Atopic asthma was highly prevalent and more frequent than non-atopic asthma in TENOR II; however frequency of exacerbations and level of control were generally similar between the two subgroups.