Responsiveness to three bronchial provocation tests in patients with asthma

Area of Science:

• Pulmonology
• Respiratory Medicine
• Diagnostic Testing

Background:

• Diagnosing mild or atypical asthma can be challenging.
• Airway hyperresponsiveness (AHR) is a key feature of asthma.
• Novel diagnostic tools are needed for difficult-to-diagnose asthma cases.

Purpose of the Study:

• To compare the sensitivity of a new mannitol bronchial provocation test against cold air and histamine challenges.
• To evaluate the effectiveness of these tests in demonstrating AHR in patients with difficult-to-diagnose asthma.

Main Methods:

• A prospective study involving 37 recently diagnosed, steroid-naive asthma patients and 10 healthy controls.
• Participants underwent spirometry, diffusion capacity measurement, skin-prick tests, and bronchial provocation tests (mannitol, cold air, histamine).
• Asthma severity was classified using the Global Initiative for Asthma (GINA) guidelines.

Main Results:

• Mannitol demonstrated AHR in 51% of asthma patients, cold air in 24%, and histamine in 81% (PD(15) < 1.0 mg) or 49% (PD(15) < 0.4 mg).
• No healthy controls responded to any challenge.
• GINA classification did not correlate with responsiveness to the provocation tests.

Conclusions:

• Mannitol is more sensitive than cold air for detecting AHR in mild or atypical asthma.
• Histamine challenge sensitivity is comparable to mannitol when using a PD(15) cut-off of 0.4 mg, considered specific for asthma diagnosis.
• The mannitol challenge offers a valuable alternative for diagnosing AHR in specific asthma populations.