NEW YORK (Reuters Health) – For patients with work-related asthma, a reduction in exposure to sensitizing agents, rather than complete avoidance, is not likely to improve the condition and is associated with an increased risk of worsening symptoms, according to a systematic review comparing these two strategies.

Writing in the European Respiratory Journal online March 24, Dr. Olivier Vandenplas, with Universite Catholique de Louvain in Yvoir, Belgium, and colleagues point out that exposure reduction has been put forward as an alternative to total avoidance of triggers in managing occupational asthma. However, the long-term effectiveness and safety of exposure reduction is uncertain.

The investigators therefore conducted a meta-analysis of data from 10 relevant studies that met inclusion criteria, 8 of which involved longitudinal follow-up of patients while 2 were retrospective surveys.

“The meta-analysis of the pooled data showed that the reduction of exposure was associated with a lower likelihood of improvement (OR: 0.16) and recovery (OR: 0.30) from asthma symptoms and a higher risk of symptom worsening (OR: 10.23) as compared with avoidance of exposure,” Dr. Vandenplas and colleagues report.

They acknowledge the socio-economic implications of work-related asthma management, but didn’t find enough analyzable information to determine if reducing exposure has a lower impact than complete avoidance of exposure.

Overall, the authors conclude that reduction of exposure cannot be routinely advocated as an alternative to the cessation of exposure.

They add, “There is a clear need for further investigation of the cost-effectiveness of the different management options of occupational asthma caused by various agents through prospective and large-scale studies based on outcomes that have been validated for the evaluation of asthma and quantitative evaluation of interventions aimed at reducing exposure.”

Reference:

Management of occupational asthma: cessation or reduction of exposure? A systematic review of available evidence


Eur Respir J 2011.