The efficacy and safety of mannitol challenge in a workplace setting for assessing asthma prevalence

ABSTRACT

Objective: There is no standard definition of asthma for epidemiological purposes; most surveys use symptoms and bronchial hyperresponsiveness. Few studies tested mannitol challenge test (MCT) in occupational settings. We sought to determine efficacy and safety of MCT in detecting subjects with asthma symptoms in the workplace. Methods: In this cross-sectional study we recruited 908 workers in 2 universities; they underwent a respiratory questionnaire, spirometry, skin prick tests, and MCT. Results: Eight hundred and eleven subjects completed the study; 11.1% had a positive MCT; 8.14% had asthma. MCT had low sensitivity (35.4–61.9%) but high specificity (90.2–94.9%) to detect symptomatic individuals. The most prevalent symptom was wheezing in the last 12 months. Twenty-four of those with a positive MCT (26.7%) had no positive replies to the questions on asthma symptoms. Among subjects with a positive MCT, 71.9% achieved 95% of baseline FEV₁ after 15 minutes of salbutamol recovery treatment. Nine subjects (1.1%) had adverse events that prevented the test from being completed. Conclusions: MCT has high specificity but low sensitivity to detect symptomatic subjects in the workplace. It may detect subjects with hyperresponsiveness but no symptoms, who could be at risk of developing airway diseases. The test is safe and well tolerated.

KEYWORDS:

• Airway hyperresponsiveness
• indirect challenges
• mannitol
• sensitivity
• specificity

Funding

São Paulo Research Foundation (FAPESP) – Brazil

Declaration of interest

Dr. John D Brannan was involved in the development of inhaled mannitol as a bronchial provocation test. Dr. Brannan's prior employer, Royal Prince Alfred Hospital, receives royalties for the sale of Aridol/Osmohale from the manufacturer, Pharmaxis Ltd. Dr. Brannan is paid a 10% portion of these royalties; however, he does not receive royalties for sales in Australia. The royalties are less than $5000 USD annually. Dr. Brannan holds less than $5000 USD in shares in Pharmaxis. No other author has a conflict of interest.

Additional information

Funding

Fundačão de Amparo à Pesquisa do Estado de São Paulo (2009/52054-1)