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

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.