Is the assessment of asthma treatment efficacy sufficiently comprehensive?

The goal of asthma guideline therapy is to achieve disease control including the minimization of impairment and decreased risk of exacerbations and adverse effects of the disease and its treatment. The primary objective of most clinical trials of biologics for severe asthma is a reduction in exacerbation rate. Recently, studies with patients at lower guideline steps have also selected exacerbations reduction as a primary objective. These trials in milder patients frequently demonstrate statistically significant fewer exacerbations but their power calculations reflect larger sample size and smaller effect size. Exacerbations have a precise consensus definition, although a minimal clinically important differences has not been established. Exacerbation reduction in severe asthma is commonly 10-fold greater than in mild disease. Further, reduction in exacerbations is not always associated with reduced impairment. If superior control is the objective, both domains should demonstrate consistent and parallel improvement. The disconnect may reflect the need for alternative tools for impairment measurement or possibly different therapeutic mechanisms of action. Determining response to biologics or discussion of disease remission requires assessing symptoms that may occur daily, rather than focus on exacerbations that occur once or twice a year for patients at the highest steps of guideline care. Asthma guidelines are now in their fourth decade of evolution.1, 2 The 2007 National Asthma Education and Prevention Program’s Expert Panel Report 3 (EPR-3)3 emphasized the importance of achieving asthma control. This pivotal document defined control: “as the degree to which the manifestations of asthma are minimized by therapeutic intervention and the goals of therapy are met.” Asthma control consists of two domains: impairment and risk. The goals of guideline therapy established are to reduce impairment by minimizing symptoms and address risk by decreasing asthma exacerbations and long-term complications from the disease and its therapy. Whether assessing optimal control over the prior 4 weeks or determining if long-term remission is achieved, clinicians need appropriate measures to properly assess asthma control. Evaluating the impairment domain requires validated tools that accurately demonstrate the absence of significant symptoms, optimization of lung function and achievement of patient and provider goals of therapy. Demonstrating risk reduction focuses on reducing severe exacerbations and limiting disease progression. Assessing both impairment and risk are required for determination of asthma control. The objective of this rostrum is to review if present evaluation methodologies are valid and appropriate across at all levels of asthma severity and control. If deficits exist, what areas need research and development to better evaluate asthma control? The goal of asthma guideline therapy is to achieve disease control including the minimization of impairment and decreased risk of exacerbations and adverse effects of the disease and its treatment. The primary objective of most clinical trials of biologics for severe asthma is a reduction in exacerbation rate. Recently, studies with patients at lower guideline steps have also selected exacerbations reduction as a primary objective. These trials in milder patients frequently demonstrate statistically significant fewer exacerbations but their power calculations reflect larger sample size and smaller effect size. Exacerbations have a precise consensus definition, although a minimal clinically important differences has not been established. Exacerbation reduction in severe asthma is commonly 10-fold greater than in mild disease. Further, reduction in exacerbations is not always associated with reduced impairment. If superior control is the objective, both domains should demonstrate consistent and parallel improvement. The disconnect may reflect the need for alternative tools for impairment measurement or possibly different therapeutic mechanisms of action. Determining response to biologics or discussion of disease remission requires assessing symptoms that may occur daily, rather than focus on exacerbations that occur once or twice a year for patients at the highest steps of guideline care. Asthma guidelines are now in their fourth decade of evolution.1, 2 The 2007 National Asthma Education and Prevention Program’s Expert Panel Report 3 (EPR-3)3 emphasized the importance of achieving asthma control. This pivotal document defined control: “as the degree to which the manifestations of asthma are minimized by therapeutic intervention and the goals of therapy are met.” Asthma control consists of two domains: impairment and risk. The goals of guideline therapy established are to reduce impairment by minimizing symptoms and address risk by decreasing asthma exacerbations and long-term complications from the disease and its therapy. Whether assessing optimal control over the prior 4 weeks or determining if long-term remission is achieved, clinicians need appropriate measures to properly assess asthma control. Evaluating the impairment domain requires validated tools that accurately demonstrate the absence of significant symptoms, optimization of lung function and achievement of patient and provider goals of therapy. Demonstrating risk reduction focuses on reducing severe exacerbations and limiting disease progression. Assessing both impairment and risk are required for determination of asthma control. The objective of this rostrum is to review if present evaluation methodologies are valid and appropriate across at all levels of asthma severity and control. If deficits exist, what areas need research and development to better evaluate asthma control?