Perception of bronchoconstriction: a complementary disease marker in children with asthma

Introduction. Asthma guidelines use symptoms as the most important aspect of asthma control. Symptom perception varies widely between individuals. Over-perception as well as underperception of bronchoconstriction could have a negative effect on asthma management. We hypothesized that perception of bronchoconstriction in childhood asthma is not related to common measures of disease control. For that reason, we examined the clinical determinants of the perception of bronchoconstriction and the repeatability of perception measurements. Patients and methods. In school-age children with moderately severe atopic asthma, we measured the perception of bronchoconstriction (decrease in forced expiratory volume in 1 second (FEV1)) during methacholine bronchoprovocation challenges. The perception of bronchoconstriction was assessed as the slope of the relation between FEV1 and Borg score, and as the Borg score at a 20% decrease in FEV1 from baseline during the provocation test (PS20). Data from subjects who had a 20% or more decrease in FEV1 (n=112) were used for the analysis. Fifty-four children repeated the test after 3 months. Symptoms, use of rescue medication, and peak expiratory flows were scored in diaries during the 2 weeks before testing. Results. Symptom perception was significantly better in children without (PD20 > 1570 mu g, n=28) than in children with airway hyperresponsiveness (PD20