Measures of perception of bronchoconstriction and clinical and functional data are not interrelated in asthma

Background: Sensitivity and absolute perceptual magnitude characterize the perception of bronchoconstriction (PB). Objectives: To define whether clinical and functional characteristics and level of bronchial hype responsiveness (BHR) correlate with these two PB indexes during bronchial challenge in asthma. Methods: PB on both the Borg scale and the visual-analogue scale (VAS) was assessed in 45 consecutive asthmatics during a methacholine-induced decrease in forced expiratory volume in 1 s (FEV1) and specifically quantified as Borg and VAS slope, as a measure of sensitivity, whereas scores at a 20% FEV1 decrease (PB20) were assessed as a measure of absolute perceptual magnitude. Clinical score and BHR were also assessed. Results: PB20 related to slope on both the Borg scale and the VAS (p < 0.0001). PB20 and slope related neither to clinical score nor to baseline functional data on both scales. The relationship between the level of BHR and PB20 on either scale was of questionable clinical significance (r(2) = 7%). Conclusions: Irrespective of the scale employed, our data indicate the need for directly assessing PB rather than deriving it from clinical and functional data and level of BHR. Copyright (C) 2002 S. Karger AG, Basel.