Background: We should continually improve tools for evaluating asthma. The aim of this study was to evaluate whether the FEV1/FVC ratio in the lower range of normality is associated with worse outcomes in asthmatics without airway obstruction.
Methods: We screened asthmatics at eight clinics. Subjects answered the Asthma Control Questionnaire and underwent spirometry. We assigned individuals without airway obstruction in three groups according to the post bronchodilator FEV1/FVC ratio: lower range of normality, intermediary range of normality and upper range of normality. Asthma outcomes were hospital admission due to asthma during the preceding year, non-controlled asthma symptoms and moderate-high inhaled maintenance therapy need.
Results: In subjects from six to 18 years old, the rate of hospital admission was higher in the group with FEV1/FVC ratio in the lower range of normality as compared with the other two groups but the frequency of non-controlled symptoms of asthma and moderate-high dose of inhaled maintenance therapy need was similar. From 19 to 59 years old, the rate of moderate-high inhaled maintenance therapy need was higher in the group with FEV1/FVC ratio in the lower range of normality as compared with the other two groups, but the frequency of hospital admissions and non-controlled symptoms of asthma was similar. Above 59 years old, there was no difference in clinical asthma outcomes between lung function groups.
Conclusions: FEV1/FVC ratio in the lower range of normality is a marker of worse clinical outcomes in asthmatics without airway obstruction.
Keywords: Asthma; Corticosteroids; Epidemiology; Exacerbation; Treatment.
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