Is the bronchodilator test an useful tool to measure asthma control?

Asthma control includes the control of symptoms and future risk. We sought to evaluate the usefulness of the degree of spirometric reversibility of the forced expiratory volume in one second (FEV₁) as the target parameter of control.

Patients with bronchial asthma were followed up for one year. The clinical, functional, inflammatory and control parameters of the asthma were collected. The area under the curve (AUC) was estimated to establish the cutoff point of the post-bronchodilator FEV₁ reversibility in relation to non-control asthma. In the univariate analysis, the differences between groups were studied based on the degree of estimated reversibility. Factors with a significance <0.1 were included in the multivariate analysis by binary logistic regression.

A total of 407 patients with a mean age of 38.1 ± 16.7 years were included. When the patients were grouped into controlled and non-controlled groups, compared with post-bronchodilator FEV₁ reversibility, the cutoff point obtained for the non-controlled group was ≥10% (sensitivity: 65.8%, specificity: 48.4%, positive predictive value: 69.5%, and AUC: 0.619 [0.533-0.700], p < 0.01). In the year-long follow-up of this group (post-bronchodilator FEV₁ ≥10), an increased use of relief medication was observed, along with a significantly progressive drop in post-bronchodilator FEV₁ and post-bronchodilator FEV₁/FVC (forced expiratory volume in one second/forced vital capacity).

Spirometric reversibility can be useful in assessing control in asthmatic patients and can predict future risk parameters. The cutoff point related to the non-control of asthma found in our work was ≥10%.