[CHARACTERISTICS OF ASTHMA PATIENTS WITH A FORCED EXPIRATORY VOLUME IN ONE SECOND/FORCED VITAL CAPACITY OF LESS THAN...

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.

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.

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.

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.