Predicted Values for Spirometry may Underestimate Long-Standing Asthma Severity

Asthma may show an accelerated lung function decline. Asthmatics, although having FEV1 and FEV1/VC (and z-scores) higher than the lower limit of normality, may show a significant FEV1 decline when compared to previous measurements. We assessed how many asymptomatic long-standing asthmatics (LSA) with normal lung function showed a significant FEV1 decline when an older FEV1 was taken as reference point