Original Article
Severe airway hyperresponsiveness was not predictable with the use of current tools in asthmatic children in general practice

https://doi.org/10.1016/j.jclinepi.2007.01.013Get rights and content

Abstract

Objective

To evaluate whether moderate to severe airway hyperresponsiveness (AHR) could be suspected with the use of routinely available clinical and environmental information.

Study Design and Setting

Cross-sectional study of asthma in 526 asthmatics aged 7–17 years and treated in general practice.

Results

Moderate to severe AHR was present in 48% (n = 253) of the participants. The presence of inhalation allergy, nocturnal symptoms, and usage of β2-mimetics were significantly associated with moderate to severe AHR. If all three factors were present, the probability of the presence of moderate to severe and severe AHR was 76% and 36%, respectively. If all three were absent, the probability decreased to 11% and 5%, respectively. In 319 subjects (64%) AHR could not be adequately predicted with routinely available information.

Conclusion

Moderate and severe AHR could not be suspected with the use of routinely available clinical and environmental information in the majority of children. Except for a subgroup of children, our models were not helpful in deciding in which child an inhaled corticosteroid should be started or whether the dose should be increased or decreased. We recommend measuring the severity of AHR in these children by means of an inhalation challenge test.

Introduction

Asthma, irrespective of the severity, is a chronic inflammatory disease of the airways associated with airway hyperresponsiveness (AHR), airflow limitation, and recurrent and often variable symptoms of wheezing, breathlessness, and cough, particularly at night [1]. The treatment of asthma is, in general, internationally agreed upon, and many national and international guidelines have been developed for the management of asthma [2], [3]. In 1995 the Global Initiative for Asthma (GINA) guidelines specified eight goals for the long-term management of asthma with the overall goal to minimize the burden of the disease in patients with asthma [4]. However, since the publication of the GINA guidelines, many studies continue to show that a substantial proportion of asthmatic children are inadequately treated [5], [6], [7].

General physicians (GPs) are the first in line to deal with asthma and asthma-related symptoms. Among the many children presenting with persistent respiratory symptoms, it is their task to select children with moderate to severe asthma. GPs are limited with respect to available tools to diagnose and monitor asthma. Compared to pediatricians who have a range of objective tools to evaluate the severity of asthma such as lung function, exhaled NO, and inhalation challenge tests, GPs use mainly presented asthma symptoms, response to asthma medication, and peak flow monitoring. It is unknown how successful GPs, with their limited tools, are in the identification of children with more severe disease. Among others, being unsuccessful may be one reason for GPs prescribing an insufficient dose of inhaled corticosteroids (ICSs), resulting in progressive worsening of the child's lung function [8], [9], [10], [11].

AHR is a surrogate marker of inflammation, reflecting the severity and level of control of the disease [12]. Children with moderate to severe AHR can be defined as a target group for treatment modification. However, testing for AHR is not a routine monitoring tool in general practice and a testing facility is often not easily accessible. Therefore, we studied whether the presence of AHR can be suspected by the GP with the use of routinely available clinical information in a group of children treated for asthma in general practice.

Section snippets

Subjects

Children were participants of an intervention study to improve childhood asthma management in general practice. They were eligible for the study if at least two prescriptions of β2-mimetics and/or an ICS were prescribed in the year before invitation. Totally 1,554 children, aged 7–17 years, were identified. Children treated by a pediatrician (n = 261) were excluded from participation. Informed consent was obtained from 539 children (response rate 42%). The medical ethics committee of the

General characteristics (Table 1)

In all, 518 of 539 children (286 boys [54%]; mean age 10.5 years) were challenged; 21 children were not challenged because of airflow limitation (FEV1 <75% of predicted) prior to the challenge. In total, 111 (21%) children were classified as having severe AHR: 90 showed severe AHR (PD20 <75 μg) and 21 children were defined as having severe AHR because of airflow limitation. In addition, 142 (27%) showed moderately severe AHR. Thirteen children were challenged, but the result was unreliable

Discussion

The question addressed by the present study was whether the presence of moderate to severe AHR can be suspected by the GP with the use of routinely available clinical information in a group of children treated for asthma in general practice. Our results show that the presence of moderate to severe AHR can be suspected to a certain extent, primarily in children using rescue medication with symptoms of nocturnal asthma and inhalant allergy. About one third of the children with moderate to severe

Acknowledgments

We would like to express our gratitude to the Health Care Organization “Zorggroep Almere” for their participation in the study. We would like to thank Paul Mulder, for his statistical assistance, as well as all participating patients and their parents. This study was sponsored with an unrestricted grant from GlaxoSmithKline.

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