Role of bronchoprovocation tests in identifying exercise-induced bronchoconstriction in a non-athletic population: a pilot study.

Background: Studies on diagnostic tests for exercise-induced bronchoconstriction (EIB) have centered around the asthmatic and elite athletic population. Traditionally, the exercise challenge test (ET) was recommended to assess EIB. We aimed to compare the performance of surrogate testing, mainly the hypertonic saline (HS) test, and methacholine challenge test (MCT) versus ET in identifying EIB among non-athletic subjects.

Methods: We prospectively recruited subjects who did not have confirmed active asthma, but who reported exercise-induced dyspnoea. The participants underwent HS and ET on separate days within two weeks. MCT performed within one year were obtained retrospectively from medical records. The sensitivity, specificity, and accuracy of each diagnostic test were calculated using ET as the gold standard.

Results: We recruited 27 participants (mean age 20.6±2.5 years; 92.6% male). Five (18.5%) had a history of self-reported asthma prior to recruitment. Eleven participants (40.7%) had a positive ET test. The sensitivity, specificity and accuracy of HS in diagnosing EIB was 90.9%, 62.5% and 74.1%; while that of MCT was 88.9%, 83.3% and 85.7% respectively. Six subjects were positive to HS but had negative ET test.

Conclusions: Both HS and MCT were found to be suitable alternatives to ET in screening for EIB in the non-athletic population in this pilot study. Further large scale studies are required to confirm this finding. These tests have the potential to replace ET for the diagnosis of EIB in centres without ET equipment or facilities.