Affordable Access

deepdyve-link
Publisher Website

Symptom evaluation during the methacholine test: Does it add to the interpretation of the test results based on the PC20FEV1?

Authors
  • Bohadana, Abraham B1
  • Wild, Pascal2
  • Izbicki, Gabriel1
  • 1 Respiratory Research Unit, (RUPI) Pulmonary Institute, Shaare Zedek Medical Center (Affiliated with the Hadassah School of Medicine, Hebrew University of Jerusalem), 12 Baiyt Street, 91031 Jerusalem, Israel. , (Israel)
  • 2 INRS - National Research and Safety Institute, 1 rue du Morvan, CS 60027, 54519 Vandoeuvre Cedex, France. , (France)
Type
Published Article
Journal
The Clinical Respiratory Journal
Publisher
Wiley (Blackwell Publishing)
Publication Date
Apr 01, 2018
Volume
12
Issue
4
Pages
1536–1544
Identifiers
DOI: 10.1111/crj.12701
PMID: 28862387
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Conventionally, symptoms occurring during the methacholine test are not taken into account when interpreting the test results. We examined whether the evaluation of methacholine-induced symptoms (MIS) added to the test interpretation based on the PC20FEV1 by assessing their prevalence, their similarity with symptoms justifying referral and their relationship with airway responsiveness. Eighty-two patients with suspected asthma completed a questionnaire of symptoms and underwent bronchial challenge with methacholine. Based on MIS and airway responsiveness (responders = PC20FEV1 < 8 mg/mL), subjects were classified as asymptomatic non-responders (ANRs), asymptomatic responders (ARs), symptomatic non-responders (SNRs) and symptomatic responders (SRs). Airway responsiveness for all subjects, including non-responders (ie, fall in FEV1 < 20%), was assessed by the methacholine concentration response-slope (MCRS) obtained using all points of the curve. ARs (n = 6) were poor-perceivers of bronchoconstriction. SNRs (n = 16) did not differ from SRs (n = 34) in any clinical parameter, including the proportion of subjects (∼80%) whose methacholine test reproduced symptoms justifying referral. In turn, SNRs differed significantly from ANRs (n = 26) by having lower baseline FEV1 (P = .005), more physician-diagnosed asthma (P < .001), more use of respiratory medication (P = .032), and relatively greater responsiveness as manifested by a steeper MCRS (P < .001). The occurrence of asthma-like symptoms during the methacholine test was associated with milder airway hyperresponsiveness that would go unnoticed by the PC20FEV1. This finding suggests that SNRs should not be merely classified as having normal responsiveness, as currently recommended, but further assessed for airway inflammation. Our results helped planning a longitudinal study to investigate the prognostic validity of this approach. © 2017 John Wiley & Sons Ltd.

Report this publication

Statistics

Seen <100 times