Adult-Onset Asthma

Abstract

Asthma in adults is composed of a complex group of reversible airway disorders in contrast to childhood asthma that is largely allergic in nature. Adult-onset asthma may be recently acquired in adulthood or represent various stages of long-standing disease. Atopic adults may carry the genotype of childhood asthma symptomatically into adulthood only to have the phenotype finally expressed because of a powerful trigger, e.g., specific aeroallergen(s) or infection. Approximately 31 million Americans suffer from asthma. The majority of patients (71%) are adults, whereas fewer than 29% (8.9 million) are children less than 18 yr of age. More women than men are affected with severe adult-onset asthma. Estrogen replacement therapy, respiratory infection with Chlamydia or Mycoplasma, certain occupations, tobacco smoking, gastroesophageal reflux, obesity, and sleep disorders are important risk factors and comorbid conditions. Asthma and active cigarette smoking interact to cause more severe symptoms, accelerated decline in lung function, and impaired short-term therapeutic response to corticosteroids (CSs). Simple spirometry, e.g., forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), detect expiratory flow limitations and lung volumes. Demonstration of reversible obstructive airways disease with spirometry after using albuterol or ipratropium in an adult older than 18 yr old does not alone diagnose adult-onset asthma. Methacholine challenge testing to exclude abnormal airway hyperresponsiveness is safe in adult-onset asthma patients with FEV1 greater than 70% predicted. High doses of inhaled CSs should be avoided in adult-onset asthma, particularly in the elderly or those with late-onset asthma. The addition of long-acting β2-agonists or antileukotriene drugs is preferable to using high doses of inhaled CSs. All patients using β2-agonists should be monitored for adverse effects, including paradoxical bronchoconstriction. Given their demonstrated benefit in conditions such as heart failure, coronary artery disease, and hypertension, cardioselective β1-blockers should not be withheld from adults with mild-moderate reversible airway disease. Patient adherence with prescribed asthma therapy is poor, and it is clearly the overwhelming explanation for poor control of asthma in adults, leading to exacerbations and hospitalizations. Compared with younger hospitalized adults, older hospitalized adults had clear deficiencies, including lower use of peak flow meters and worse asthma self-management knowledge. Factors independently associated with hospitalization included being female, nonwhite, less educated, and less physically healthy and more frequent asthma symptoms. Chronological age was not an independent risk for hospitalization. Appropriate care for older adults with asthma should address asthma symptoms as in children and younger adults.