Predictors of asthma exacerbation among patients with poorly controlled asthma despite inhaled corticosteroid treatment

Background Asthma exacerbations are associated with decreased quality of life and increased health care usage. Identification of characteristics that predict increased risk of future exacerbations in patients with suboptimal control of asthma could guide treatment decisions. Objective To examine patient characteristics associated with risk of asthma exacerbations in patients with uncontrolled persistent asthma. Methods A retrospective analysis of adults and children with inadequately controlled asthma despite asthma controller therapy and enrolled in 2 randomized trials was conducted. Baseline characteristics of subjects who experienced an asthma exacerbation during the treatment period were compared with those of subjects who did not experience an exacerbation. Results Of 718 subjects (402 adults and 295 children), 108 adults (27%) and 110 children (37%) experienced an asthma exacerbation during the study period. Unscheduled health care visits for asthma or use of oral corticosteroids in the previous year were significantly associated with asthma exacerbation during the study period (P <.01). Adult subjects who experienced an exacerbation had significantly lower forced expiratory volume in 1 second compared with those who did not (2.3 vs 2.5 L, respectively, P =.02). Children who experienced an exacerbation had lower baseline pre- and post-bronchodilator ratios of forced expiratory volume in 1 second to forced vital capacity (77% vs 81%, P <.01; 82% vs 86%, P <.001, respectively). Symptom scores on validated questionnaires were significantly worse in adults but not in children who developed an exacerbation. Conclusion Spirometric measurements can help identify adults and children at increased risk for asthma exacerbation. Symptom scores could be helpful in identifying adults who are at high risk for exacerbations but could be less helpful in children.