Exhaled nitric oxide is of limited value in the diagnosis of occupational asthma

Impact of occupational asthma on health and employment status: a long-term follow-up study

OBJECTIVES

The aim of this study was to assess the predictors of a favourable prognosis of occupational asthma (OA) and the employment status of patients with OA at least 2 years after diagnosis.

METHODS

We collected data from 204 patients who had a diagnosis of OA confirmed by a positive specific inhalation challenge. We defined OA remission as meeting the following three criteria: no asthma symptoms, no antiasthma therapy for the last year and having normal lung function at the end of follow-up. A logistic regression analysis was performed to estimate the effects of the covariates.

RESULTS

At 10.6±7.8-year follow-up, 60 of 204 possible patients participated in the study, and among them 17 showed OA remission. When compared with the 43 patients with persistent OA, these patients exhibited at diagnosis younger age (p=0.0039), shorter duration of symptomatic exposure (p=0.0512), better lung function expressed by higher forced vital capacity (FVC%) predicted (p=0.0164), forced expiratory volume in 1 s (FEV₁) % predicted (p=0.0066) and FEV₁/FVC% (p=0.0132), and less bronchial hyper-responsiveness (p=0.0118). Nevertheless, in the multivariable model, no variables were significantly associated with OA remission. At follow-up, three individuals have retired; among the remaining 57 workers, 91.2% were still employed and 43.8% of them had continued working in the same factory after ceasing exposure to the causative agent.

CONCLUSIONS

This monocentric study did not identify a strong predictor of OA remission, but documented a high employment rate and a good job preservation over a long timeframe after diagnosis of OA mainly induced by low molecular weight agents.

EAACI position paper on the clinical use of the bronchial allergen challenge: Unmet needs and research priorities

Allergic asthma (AA) is a common asthma phenotype, and its diagnosis requires both the demonstration of IgE-sensitization to aeroallergens and the causative role of this sensitization as a major driver of asthma symptoms. Therefore, a bronchial allergen challenge (BAC) would be occasionally required to identify AA patients among atopic asthmatics. Nevertheless, BAC is usually considered a research tool only, with existing protocols being tailored to mild asthmatics and research needs (eg long washout period for inhaled corticosteroids). Consequently, existing BAC protocols are not designed to be performed in moderate-to-severe asthmatics or in clinical practice. The correct diagnosis of AA might help select patients for immunomodulatory therapies. Allergen sublingual immunotherapy is now registered and recommended for controlled or partially controlled patients with house dust mite-driven AA and with FEV1 ≥ 70%. Allergen avoidance is costly and difficult to implement for the management of AA, so the proper selection of patients is also beneficial. In this position paper, the EAACI Task Force proposes a methodology for clinical BAC that would need to be validated in future studies. The clinical implementation of BAC could ultimately translate into a better phenotyping of asthmatics in real life, and into a more accurate selection of patients for long-term and costly management pathways.