NCT02318043

AMP-BPT and His-BPT for Assessment of Asthma

Is Adenosine Monophosphate Superior to Histamine for Bronchial Provocation Test in Evaluation of Asthma?

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 84 (actual)
• Sponsor: Guangzhou Institute of Respiratory Disease · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

Summary

Adenosine monophosphate (AMP) may reflect airway inflammation and hyperresponsiveness, but relationship between AMP and histamine (His, a conventional stimulus) bronchial provocation test (BPT) in asthma is not fully elucidated. The investigators aimed to compare both BPTs and determine their usefulness in reflecting changes of asthmatic symptoms. BPTs were performed in cross-over fashion, at 2-4day intervals. Cumulative doses eliciting 20% FEV1fall (PD20FEV1), diagnostic performance and adverse events were compared. Patients with PD20FEV1 lower than geometric mean were defined as responders, otherwise poor responders. Patients with uncontrolled and partly controlled asthma, who maintained their original inhaled corticosteroids therapy, underwent reassessment of airway responsiveness and asthmatic symptoms 3 and 6 months after.

Detailed description

Airway hyperresponsiveness, the pivotal feature of asthma, can be assessed by bronchial provocation tests (BPTs), which may elicit bronchoconstriction via inhalation of stimuli. Histamine has been a direct stimulus for inducing bronchoconstriction via vasodilation, eosinophil chemotaxis and tissue edema. Clinically, histamine BPT (His-BPT) has gained extensive application for decades owing to the assay sensitivity and feasibility, but could not ideally predict anti-inflammatory treatment outcomes in practice. Additionally, mild adverse events (flushing and hoarseness) and insufficient capacity of identifying exercise-induced asthma have hampered further clinical applications. Adenosine monophosphate (AMP) is an inflammatory mediator that serves as an indirect bronchial stimulus for detecting airway hyperresponsiveness in asthma. Compared with histamine, AMP may be pathophysiologically more relevant to airway inflammation and hyperresponsiveness and has been linked to presence and magnitude of atopy. However, differences of response to AMP-BPT and His-BPT in different asthma control levels and their associations with asthmatic symptom scores have not been fully elucidated. We hypothesized that asthmatic patients, regardless of control levels, responded differentially to AMP-BPT and His-BPT, and that greater reduction in airway responsiveness to AMP (esp. responders of AMP-BPT) was associated with significant symptom alleviation. Henceforth, we sought to: 1) compare diagnostic performance and safety of AMP-BPT and His-BPT in different asthma control levels; 2) determine the association between airway responsiveness and asthmatic symptom scores. Currently, His-BPT is recommended by the Chinese guideline and shares considerable similarity with methacholine (another conventional stimulus) BPT, we therefore did not perform the latter in this study.

Conditions

• Asthma

Interventions

Type	Name	Description
DRUG	inhaled corticosteroids (usually budesonide/fomorterol 160/4.5mcg; fluticasone/salmeterol 250/50mcg)	Patients with uncontrolled and partly controlled asthma, following accomplishment of study 1, were invited to participate in observational study (study 2), which sought to determine usefulness of both BPTs in reflecting improvement of asthmatic symptoms following 3 and 6 months of moderate-dose ICSs treatment (400\~800μg budesonide or equivalent). Patient continued to administer their original ICS during follow-up. During two follow-up visits (3 months apart), AMP-BPT, His-BPT and Hogg's symptom scores were reassessed.

Timeline

• Start date: 2007-01-01
• Primary completion: 2007-12-01
• Completion: 2007-12-01
• First posted: 2014-12-17
• Last updated: 2014-12-17