Clinical Burden and Predictors of Asthma Exacerbations in Patients on Guideline-based Steps 4-6 Asthma Therapy in the TENOR Cohort (original) (raw)

What is already known about this topic? Patients with severe or difficult-to-treat asthma have high rates of asthmarelated health care utilization and medication use. Asthma exacerbations are an important predictor of future exacerbations and have been investigated in the overall TENOR (The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens) cohort. What does this article add to our knowledge? This study characterizes the clinical burden of disease and risk of asthma exacerbations in a subcohort of TENOR patients with more severe disease who were being treated with National Heart, Lung, and Blood Institute Steps 4/5/6 therapy. How does this study impact current management guidelines? Patients with severe or difficult-to-treat asthma who are on Steps 4/5/6 therapy have substantial clinical burden and risk of exacerbations. Improved treatment strategies, therapies, and management of risk factors may improve asthma-related health outcomes in these patients. BACKGROUND: Patients with severe or difficult-to-treat asthma on guideline-recommended Steps 4/5/6 therapy have not previously been described. OBJECTIVE: To characterize patients with severe or difficult-totreat asthma on Steps 4/5/6 therapy and assess predictors of future asthma exacerbations. METHODS: Patients ages ‡12 years with baseline and month 12 medication data were assigned to Steps 4/5/6 care levels from the 2007 National Heart, Lung, and Blood Institute guidelines. Demographic, atopic, and clinical characteristics at baseline and month 12 were assessed by using descriptive statistics. Asthma-related quality of life was assessed by using the Mini Asthma Quality of Life Questionnaire, and work and activity impairment was assessed by the Work Productivity and Activity Impairment Questionnaire-Asthma. Odds ratios (OR) and 95% CI for asthma exacerbation risk at month 12 were generated by using multivariable logistic regression. RESULTS: A total of 1186 patients were included. More than two-thirds of the patients (67.4%) were on ‡3 long-term controllers, and 55.1% were considered difficult to treat due to frequent exacerbations. Patients reported low asthma-related quality of life scores and considerable impairment in overall work and daily activity (21.4% and 32.1%, respectively). After adjustment for covariates, exacerbation history (hospitalization, OR 6.27 [95% CI, 3.61-10.88]; emergency department visit, OR 3.84 [95% CI, 2.50-5.91]; corticosteroid burst, OR 2.89 [95% CI, 2.18-3.82]) and very poorly controlled asthma (OR 1.95 [95% CI, 1.41-2.71] vs not well controlled) were independently associated with risk of a future exacerbation (all P < .001). CONCLUSION: Despite multiple long-term controller medications, patients with severe or difficult-to-treat asthma on Steps 4/5/6 therapy present with significant clinical burden and risk of future asthma exacerbations.