Relation of the perception of airway obstruction to the severity of asthma

• Published in: Thorax Vol. 54; no. 1; pp. 15 - 19
• Main Authors: Bijl-Hofland, I D, Cloosterman, S G M, Folgering, H Th M, Akkermans, R P, van Schayck, C P
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Thoracic Society 01-01-1999; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adolescent; Adult; Age; Airway management; airway obstruction; Airway Obstruction - physiopathology; Airway Obstruction - psychology; Asthma; Asthma - physiopathology; Asthma - psychology; Biological and medical sciences; Bronchial Provocation Tests; Chronic obstructive pulmonary disease, asthma; Dyspnea - etiology; Dyspnea - physiopathology; Female; Forced Expiratory Volume - physiology; Humans; Male; Medical sciences; Middle Aged; Original; Patients; Perception; Pneumology; Risk Factors; Studies; Human; Respiratory tract; Respiratory disease; Perception; Severity score; Obstructive pulmonary disease; Diagnosis; Maximal expiratory volume per second; Obstruction; Asthma
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thx.54.1.15

BACKGROUND Patients with a poor perception of their symptoms of asthma seem to have an increased risk of an asthma attack. The influence of factors such as airway calibre, bronchial hyperresponsiveness, age and sex on the “perceptiveness” of a patient are poorly understood. It is of clinical importance to identify patients who are likely to have a poor perception of their symptoms. We have studied the perception of bronchoconstriction by asthmatic patients during a histamine provocation test and analysed the influence of bronchial obstruction, hyperresponsiveness, sex, and age. We were particularly interested to establish whether there was any difference in perception between subjects with a greater or lesser severity of asthma (expressed as bronchial obstruction, hyperresponsiveness). METHODS One hundred and thirty four patients with allergic asthma underwent a histamine provocation test. The FEV1 was measured after each inhalation of histamine. Subjects were asked to rate subjective quantification of the sensation of breathlessness on a visual analogue scale (VAS). The relationship between changes in VAS values and the reduction in FEV1 as a percentage of the baseline value was analysed by determining the linear regression slope (α) between the two parameters and indicates the perception of airway obstruction. Multiple regression analysis was performed to investigate the effect of baseline FEV1, bronchial hyperresponsiveness, sex and age on the “perceptiveness” for bronchoconstriction. RESULTS The median value of the slope α (indicating the perception of airway obstruction) was 0.91 (25–75th percentile: 0.48–1.45). Age and sex had no influence on the perception of bronchoconstriction. Both initial bronchial tone (baseline FEV1) and bronchial hyperresponsiveness (PC20) showed a significant correlation with the perception of bronchoconstriction. The regression coefficients for FEV1 and 2log PC20 in the multiple regression model were 0.20 and 0.10. Patients who had a low baseline FEV1 and/or a high bronchial responsiveness to histamine were more likely to show a low perceptiveness for bronchoconstriction during the challenge test. CONCLUSIONS Low baseline FEV1 and high bronchial responsiveness are associated with a low degree of “perceptiveness” for bronchoconstriction. This suggests that patients with a more severe degree of asthma either show adaptation of “perceptiveness” for airway obstruction or that low perceptiveness leads to more severe asthma.