Published Online: July 8, 2014
Prior asthma exacerbations increase the short term risk of subsequent asthma exacerbations. However, few data exist regarding the natural history of asthma exacerbations over time. In a report recently published in The Journal of Allergy and Clinical Immunology: In Practice, Schatz and colleagues report the results of a study designed to evaluate the frequency and risk factors of asthma exacerbation occurrence over a 5 year period in a large cohort of adult patients with persistent asthma.
Health insurance claims for years 2006-2011 were analyzed for 2,543 patients with persistent asthma who were treated with high dose inhaled corticosteroids and long-acting-β2-agonists for at least 120 days (“high intensity” therapy) in 2006. A retrospective analysis was conducted to assess the pattern over time of total exacerbations (encounter with health care system and steroid burst), including those requiring hospitalizations. In addition, associations between exacerbations over time and other measures of health status were explored.
Despite the use of high intensity asthma therapy, there was only a small decrease over time in the proportion of patients who experienced any asthma exacerbations (28 % in 2007, 25 % in 2011, Odds ratio (OR) 0.96, 95 % Confidence Interval (CI) 0.94-0.99). No significant time trends for exacerbation rate or asthma hospitalizations were observed. An exacerbation in the prior year increased the risk for exacerbations almost 8-fold (OR 7.8, CI 7.1- 8.6) over the course of the study. A 50% increase in exacerbation risk (OR 1.5, 95 % CI 1.4 -1.6) was associated with continued high intensity treatment for the duration of the study. Patients with encounters for chronic obstructive pulmonary disease (COPD) after the index year were at 60% increased risk of an exacerbation (OR 1.59, CI 1.44-1.75).
This study shows that exacerbation rates for asthma patients on high-intensity therapy in a real-world setting remain relatively constant over time, and continuous high treatment intensity is not associated with a substantially lower risk of exacerbations. These findings suggest that either present therapies require further optimization or more effective novel therapies are needed for patients experiencing asthma exacerbations in spite of high intensity pharmacologic treatment.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.