RT Journal Article SR Electronic T1 Lessons learned from the epidemiology and natural history of asthma: Outcomes and treatment regimens (TENOR) JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1413 VO 38 IS Suppl 55 A1 Bradley Chipps A1 Ashley Yegin A1 Larry Borish A1 Sally Wenzel A1 Scott Weiss A1 Mary Hayden A1 Dave Miller A1 Eugene Bleecker A1 Estelle Simons A1 Stan Szefler A1 Robert Zeiger A1 Tmirah Haselkorn YR 2011 UL http://erj.ersjournals.com/content/38/Suppl_55/1413.abstract AB Rationale: Patients with severe or difficult-to-treat asthma are an understudied population. The primary objective of The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study is to characterize the natural history of disease in the largest cohort of severe or difficult-to-treat asthma patients. We highlight the main findings of 25 research articles.Methods: TENOR was a 3-year, multicenter, observational cohort study of N=4,756 patients (n=3,489 adults ≥18 years; n=627 adolescents 12-17 years; n=637 children 6-11 years). Data was collected semi-annually and annually.Results: Regardless of age, patients demonstrated high rates of HCU, despite receiving multiple long-term controller medications. Uncontrolled asthma, per the NHLBI guidelines, is highly prevalent and predictive of future asthma exacerbations in children and adolescents/adults. Children have an increased exacerbation risk and asthma burden compared with adolescents/adults. Increased weight is associated with worse asthma related outcomes. Aspirin sensitivity is associated with increased asthma severity and possible remodeling of both the upper and lower airways. Also, the phenotypes of persistent airflow are described. IgE and allergy play an important role in severe or difficult-to-treat asthma. Quantitative results not listed due to space constraints.Conclusions: Patients with severe or difficult-to-treat asthma demonstrate an unmet need. The characterization of this cohort has improved our understanding of asthma control and exacerbations.