Impact of ‘mild’ asthma on health outcomes: findings of a systematic search of the literature

Abstract

The present bibliographic review shows that patients considered to have mild asthma often suffer impairment in quality of life (QoL) and use considerable scheduled and unscheduled health care resources. I found that asthma investigators used no consistent classification scheme for asthma severity, and the level of agreement amongst specialists when categorizing patients with asthma was low. Asthma severity has been classified using a wide range of parameters including medication use, asthma symptoms, lung function, hospitalizations and incidence of exacerbations. Most studies showed a general association between asthma severity and health-related quality of life (HRQoL) such that patients with severe disease suffered greater impairment. However, few patients with mild asthma enjoyed unimpaired HRQoL. Indeed depression and impaired HRQoL were reported as frequently in patients with mild asthma as in those with more severe disease. Although in general severe patients used the most health care resources, even patients with mild asthma used considerable health care resources including emergency room care and hospitalizations. In summary, the term 'mild' when applied to asthma is potentially misleading given the impaired HRQoL and avoidable health care utilization prevalent amongst such patients. The application of disease severity classification in clinical asthma management has not been validated. It may now be appropriate to examine these classifications more critically in order to determine if they have clinical or research usefulness. By contrast, the strategy of treating to achieve disease control has been validated and offers the advantage of simplicity in its application.

Does continuous use of inhaled corticosteroids improve outcomes in mild asthma? A double-blind randomised controlled trial

“…3 However, at a population level, mild asthma is associated with substantial use of health care resources. 27 Serious exacerbations do occur in patients with mild asthma, 6,28 even if their baseline FEV1 is >80% predicted, 6 and severe exacerbations are significantly reduced by low dose ICS. 4,6 Although large sample sizes and long-term studies are required for the formal study of severe exacerbations, features such as airway obstruction, airway hyperresponsiveness and airway inflammation are independent predictors of exacerbations, [29][30][31] and can be used as surrogate measures for future risk.…”

International Differences in Asthma Guidelines for Children

“…This growing emphasis on control reinforces the components of chronic disease management, such as regular evaluation, achieving target outcomes and tailored therapy [12, 39, 42, 43]. This approach acknowledges that severity is a determinant of asthma control [38, 40, 42] but does not dictate the means to achieve it [44].…”

Asthma that is unresponsive to usual care

“…4,13 A separate issue from symptom control is the definition of asthma severity. 6,14 Frequent symptoms and exacerbations are not synonymous with severe disease. Patients with mild disease may have frequent symptoms or exacerbations if adequate maintenance therapy has not been prescribed or they are not taking their prescribed medications.…”