[CHARACTERISTICS OF ASTHMA PATIENTS WITH A FORCED EXPIRATORY VOLUME IN ONE SECOND/FORCED VITAL CAPACITY OF LESS THAN 70% IN A BRONCHODILATOR INHALATION TEST].

Abstract

Background: The present study aimed to investigate the clinical characteristics and bronchodilator inhalation (BDI) responsiveness of asthma patients whose forced expiratory volume in one second to forced vital capacity ratio (FEV₁/FVC) remained below 70% after BDI.

Methods: This retrospective observational study included 130 patients diagnosed with asthma by respiratory specialists who had undergone airway reversibility test, and whose diagnoses could be confirmed from medical records.

Results: Among the 130 patients, 91 showed a post-BDI FEV₁/FVC ≥70% (N group), while 39 showed a post-BDI FEV₁/FVC <70% (O group). Peripheral blood eosinophil counts were significantly higher in the O group, whereas no other background factors differed between the groups. Before BDI, the percentage predicted FEV₁ (%FEV₁) and the percentage predicted forced vital capacity (%FVC) were significantly lower in the O group. After BDI, %FEV₁ remained lower in the O group, whereas %FVC did not differ significantly between the two groups. Both the absolute and relative increases in FEV₁ and FVC following BDI were greater in the O group. In the O group, the absolute increases in FEV₁ and FVC were comparable, whereas in the N group, the increase in FVC was smaller than that in FEV₁. The proportion of patients meeting criteria for airway reversibility (≥10% improvement in either FEV₁ or FVC from predicted values) was significantly higher in the O group.

Conclusion: Asthma patients with a post-BDI FEV₁/FVC <70% had more severe obstructive ventilatory impairment; however, their bronchodilator responsiveness was preserved, with a particularly marked improvement in FVC.