The following is a summary of “Bronchodilator response does not associate with asthma control or symptom burden among patients with poorly controlled asthma,” published in the NOVEMBER 2023 issue of Pulmonology by Kaminsky, et al.
For a study, researchers sought to investigate the relationship between four different definitions of bronchodilator response (BDR) and asthma control, as well as the burden of asthma symptoms in a large population of individuals suffering from poorly controlled asthma.
The research involved analyzing baseline changes in FEV1 (Forced Expiratory Volume in one second) and FVC (Forced Vital Capacity) in response to albuterol, a bronchodilator. The study encompassed 931 poorly controlled asthma participants pooled from three clinical trials conducted by the American Lung Association – Airways Clinical Research Centers. Four distinct definitions of BDR were applied, and their associations with asthma control, evaluated using the Asthma Control Test or Asthma Control Questionnaire, and asthma symptom burden, assessed through the Asthma Symptom Utility Index, were analyzed.
The study observed a BDR in 31–42% of all participants, depending on the specific definition employed. These definitions displayed good agreement among responses, with kappa coefficients ranging from 0.73 to 0.87. However, only 56% of participants met all four BDR definitions. Notably, BDR was more prevalent in men than women, in Black individuals in contrast to White individuals, among non-smokers versus smokers, and in non-obese participants compared to obese ones. Among those with poorly controlled asthma, 35% exhibited a BDR, whereas this figure was 25% among those with well-controlled asthma. Similarly, among individuals with a high symptom burden, 34% demonstrated a BDR, compared to 28% in individuals with a low symptom burden. However, after adjusting for age, sex, height, race, obesity, and baseline lung function, none of the four BDR definitions is associated with asthma control or symptom burden.
The study’s findings suggested that a bronchodilator response, regardless of the definition, was not linked to asthma control or symptoms in individuals with poorly controlled asthma. Consequently, the clinical utility of assessing asthma control and symptoms based on a BDR is questioned.