Accuracy of perception of severity of asthma: patients treated in general practice

Abstract

Objective: To determine the frequency of poor perception of severity of asthma in general practice.

Design: Asthmatic patients recorded their perceived severity of asthma, with a visual analogue score, and a coded measurement of their peak expiratory flow up to four times daily for 14 consecutive days.

Settings: 11 general practices in and around Bristol.

Subjects: 255 asthmatic patients (139 men and 116 women) aged 17-76 who were recruited by random selection from the general practices' disease registers or when they requested prescriptions for inhaled bronchodilators.

Main outcome measures: Correlation between visual analogue scores and peak expiratory flow (as a percentage of predicted peak flow).

Results: 152 (60%) of the patients showed no significant correlation between visual analogue asthma scores and simultaneous peak flow measurements (p > 0.05) and were termed poor discriminators. The distribution of good and poor discriminators within each general practice was similar (chi 2 = 6.11, df = 10). The two groups were not characterised by differences in the maximum, minimum, or standard deviation of peak expiratory flow or visual analogue score; in age; or in the proportion of men and women in each group.

Conclusions: In general practice a high proportion of asthmatic patients do not reliably detect changes in their lung function. This reinforces the need for careful objective assessment of lung function in the management of asthma.