Abstract and Introduction
Abstract
Asthma is a common chronic disease with underlying inflammation of the airway. Advances in science have led to increased understanding of the heterogeneous nature of asthma and its complex mechanisms. Traditionally, asthma-practice guidelines have focused on optimizing lung function and the US FDA has required increases in lung function and reduction of exacerbation as primary outcomes in clinical trials of new asthma therapeutics. Improved lung function is a critical indicator of bronchodilator therapy, but the importance of long-term asthma control while maintained on controller medication is increasingly emphasized. The NIH asthma guidelines suggest the use of patient-reported outcomes, including health-related quality-of-life measures, to assess asthma control. Clinical practices and research studies concerning asthma can benefit from harmonizing the major outcome measures so that comparisons across studies can be made. In this article, we review common asthma outcome measures with a focus on recent efforts to harmonize outcomes for therapeutic clinical trials in asthma.
Introduction
Asthma is a common chronic disease with underlying inflammation of the airway that affects more than 300 million people worldwide and 25 million people in the USA.[101] Advances in science have increased understanding of the heterogeneous nature of asthma and its complex mechanisms. Asthma comprises asthma symptoms, variable airflow obstruction, airway hyper-responsiveness (AHR) and underlying inflammation.[1,102] The goals of asthma treatment are not only controlling the patient's current symptoms, but also preventing recurrent asthma exacerbations (AEs). As noted by the US FDA, bronchodilators may control symptoms and lung function in the short term, but use of long-acting bronchodilators without the concurrent use of an inhaled corticosteroid is dangerous because bronchodilators do not reduce airway inflammation or AHR. Asthma management needs to optimize the patient's current clinical state and prevent adverse outcomes, including AEs and side effects of the therapeutics.
Identifying relevant short-term and long-term outcome measures is critical for the management of asthma and evaluating the efficacy and effectiveness of therapeutic interventions. The criteria used to assess asthma outcomes have varied widely from study to study. When asthma is poorly controlled, the patient's activities tend to be restricted, their role function is limited and their work productivity is reduced. In addition, they may require unscheduled, urgent use of healthcare. Hence, patient-reported outcomes, including health-related quality of life (HRQOL), are important indicators of asthma control.
Clinical practices and research studies in asthma can benefit from harmonizing the major outcomes so that comparison across studies can be made and meta-analyses performed, thereby contributing to comparative effectiveness research. In this article, we review asthma outcome measures with a focus on recent efforts to standardize outcomes for therapeutic clinical trials in asthma and with attention to HRQOL.
Expert Rev Pharmacoeconomics Outcomes Res. 2011;11(4):447-453. © 2011 Expert Reviews Ltd.
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