Risk factors associated with persistent airflow limitation in severe or difficult-to-treat asthma: insights from the TENOR study

Chest. 2007 Dec;132(6):1882-9. doi: 10.1378/chest.07-0713.


Background: The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens study is among the largest to assess persistent airflow limitation and the first to evaluate a wide range of potential risk factors in high-risk patients with severe or difficult-to-treat asthma. A better understanding is needed regarding factors associated with persistent airway obstruction; this study was performed to determine demographic and clinical characteristics associated with persistent airflow limitation.

Methods: Data from adult patients (>or= 18 years old) with severe or difficult-to-treat asthma were evaluated. Patients with COPD, obesity with a restrictive respiratory pattern, or a >or= 30 pack-year history of smoking were excluded. Patients with persistent airflow limitation (postbronchodilator FEV1/FVC ratio <or= 70% at two annual consecutive visits) and normal postbronchodilator FEV1/FVC ratio (75 to 85%) were compared. Multivariate analysis identified factors independently associated with persistent airflow limitation.

Results: Of 1,017 patients, 612 patients (60%) showed evidence of persistent airflow limitation. Risk factors were as follows: older age (odds ratio [OR] per 10 years, 1.4; 95% confidence interval [CI], 1.3 to 1.6); male gender (OR, 4.5; 95% CI, 2.3 to 8.5); black ethnicity (OR, 2.2; 95% CI, 1.3 to 3.8); current or past smoking (OR, 3.9; 95% CI, 1.8 to 8.6; and OR, 1.6; 95% CI, 1.2 to 2.3, respectively); aspirin sensitivity (OR, 1.5; 95% CI, 1.0 to 2.4); and longer asthma duration (OR per 10 years, 1.6; 95% CI, 1.4 to 1.8). Protective factors were Hispanic ethnicity, higher education, family history of atopic dermatitis, pet(s) in the home, and dust sensitivity.

Conclusions: Persistent airflow limitation is prevalent in patients with severe or difficult-to-treat asthma and is associated with identifiable clinical and demographic characteristics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asthma / physiopathology*
  • Bronchoconstriction*
  • Chi-Square Distribution
  • Disease Progression
  • Female
  • Forced Expiratory Volume
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Prospective Studies
  • Risk Factors
  • Severity of Illness Index
  • Spirometry
  • Surveys and Questionnaires
  • Vital Capacity