Do subjects investigated for occupational asthma through serial peak expiratory flow measurements falsify their results?

doi:10.1016/S0091-6749(95)70258-X

Journal of Allergy and Clinical Immunology

Volume 96, Issue 5, November 1995, Pages 601-607

https://doi.org/10.1016/S0091-6749(95)70258-X Get rights and content

Abstract

Background and aim: Serial assessment of peak expiratory flow (PEF) rates has been advocated as a sensitive and specific means of investigating occupational asthma. The possibility that, for several reasons, subjects do not accurately report their values has been raised. The availability of portable instruments that assess PEF and store timings and values now makes it possible to estimate compliance and accuracy of results. Methods: Twenty-one subjects consecutively investigated for occupational asthma were asked to assess their PEF every 2 hours during the day, both at work and away from work, with a VMX instrument (Clement Clarke International, Columbus, Ohio) and record the times and values on a sheet of paper. The subjects were not aware that the data were also being stored on a computer chip. The diagnosis was occupational asthma in eight subjects, personal asthma in four subjects, and neither condition in nine subjects. Results: The mean duration of recording was 36 days (range, 14 to 79 days). At least 6048 values should have been recorded, but only 4839 (80%) were either recorded or stored. Reported values corresponded precisely to stored values in 2533 of 4839 recordings (52%). The timing of the recording was also examined in relation to the time at which the recording was solicited; values recorded within 1 hour of the solicited time were judged as acceptable. Of the total of 3342 recordings stored, 2375 (71%) satisfied this criterion. Compliance was significantly less satisfactory in those referred by the Workers' Compensation Board (n = 11). Conclusion: In this survey of 21 subjects investigated for possible occupational asthma, compliance with PEF recording, as assessed by comparing recorded and stored results and the time at which the recording was solicited, was poor. (J ALLERGY CLIN IMMUNOL 1995;96:601-7.)

Section snippets

Subjects

The data kept for analysis came from 21 prospectively recruited subjects who attended a specialized occupational asthma clinic and who met the following criteria: at least 2 weeks of PEF monitoring at work and 2 weeks away from work in the case of subjects with a diagnosis of occupational asthma and at least 2 weeks of PEF monitoring at work in the case of subjects without a confirmed diagnosis of occupational asthma. Patients were either referred by their general practitioner or a specialist

RESULTS

Some of the baseline anthropometric, clinical, and functional results are listed in Table I. The majority of subjects were men under 55 years of age and taking either no medication or an inhaled β₂-adrenergic agent only as needed. The most commonly incriminated agents at work were isocyanates (hexamethylene diisocyanate only) among spray painters in body shops and flour among bakers. A diagnosis of occupational asthma was retained in eight subjects, of personal asthma in five subjects, and of

DISCUSSION

This study shows that the compliance with PEF monitoring in the investigation of occupational asthma was poor in our sample of 21 asthmatic subjects prospectively assessed. Subjects were asked to record three PEF values eight times per day for a mean duration of 36 days. This is the method for which we previously showed a sensitivity of 81% and a specificity of 74%.⁷ At least 6048 values should have been recorded and stored in the VMX apparatus (this excludes some values, which should have been

Acknowledgements

We thank Katherine Tallman for reviewing the manuscript.

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How many times per day should peak expiratory flow rates be assessed when investigating occupational asthma?

Thorax

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Cited by (74)

Reply
2016, Journal of Allergy and Clinical Immunology
Asthma in the Workplace
2015, Murray and Nadel's Textbook of Respiratory Medicine: Volume 1,2, Sixth Edition
Clinical Assessment of Occupational Asthma and its Differential Diagnosis
2011, Immunology and Allergy Clinics of North America
Citation Excerpt :
On one hand, PEF may greatly underestimate or overestimate changes in airway caliber as assessed by FEV1.35–37 On the other hand, they are effort dependent and, thus, require the cooperation of the worker, which is not always obtained because of the fear of losing his or her job or malingering to gain compensation benefits.38,39 The combination of NABR monitoring and PEF monitoring at work and off work is now frequently used in the investigation of OA.
Occupational agents
2009, Asthma and COPD
Occupational agents (OA) is a disease characterized by variable airflow limitation and/or airway hyperresponsiveness and/or inflammation due to causes and conditions attributable to a particular occupational environment and not to stimuli encountered outside the workplace. Over 300 agents in the workplace have been implicated in causing asthma. The agents can be divided into two groups according to the pathogenic mechanisms: those that give rise to asthma by immunological mechanisms and those by nonimmunological mechanisms. Agents in the former group can cause asthma by immunoglobulin (Ig)E-dependent or IgE-independent mechanisms. Irritant-induced asthma (IIA) is a type of OA caused by an apparently nonimmunological mechanism. Many patients may have been exposed to multiple sources, and the relative contributions of each may be impossible to disentangle. COPD is the symptomatic and functional consequence of chronic exposure to these polluted air sources. Therefore, it seems appropriate to pose a definition for occupational COPD that allows it to coexist with “smoking-induced COPD” or “urban air pollution-induced COPD.” Asthma is a common respiratory occupational ailment. Whereas improvement in diagnostic tools and pathophysiological mechanisms still need to be considered, emphasis should be put on prevention programs through identification and application of permissible respirable levels and of affected subjects at an early stage of sensitization or disease to prevent long-term sequelae of permanent asthma.
Occupational Agents
2008, Asthma and COPD: Basic Mechanisms and Clinical Management
Occupational agents (OA) is a disease characterized by variable airflow limitation and/or airway hyperresponsiveness and/or inflammation due to causes and conditions attributable to a particular occupational environment and not to stimuli encountered outside the workplace. Over 300 agents in the workplace have been implicated in causing asthma. The agents can be divided into two groups according to the pathogenic mechanisms: those that give rise to asthma by immunological mechanisms and those by nonimmunological mechanisms. Agents in the former group can cause asthma by immunoglobulin (Ig)E-dependent or IgE-independent mechanisms. Irritant-induced asthma (IIA) is a type of OA caused by an apparently nonimmunological mechanism. Many patients may have been exposed to multiple sources, and the relative contributions of each may be impossible to disentangle. COPD is the symptomatic and functional consequence of chronic exposure to these polluted air sources. Therefore, it seems appropriate to pose a definition for occupational COPD that allows it to coexist with “smoking-induced COPD” or “urban air pollution-induced COPD.” Asthma is a common respiratory occupational ailment. Whereas improvement in diagnostic tools and pathophysiological mechanisms still need to be considered, emphasis should be put on prevention programs through identification and application of permissible respirable levels and of affected subjects at an early stage of sensitization or disease to prevent long-term sequelae of permanent asthma.
The diagnosis and management of occupational asthma
2008, Revue des Maladies Respiratoires
L’asthme professionnel avec période de latence induite après des expositions répétées, se caractérise par une sensibilisation immunologique à l’agent responsable pouvant être IgE- dépendante, et une hyperréactivité bronchique non spécifique.
L’interrogatoire est un élément capital des investigations de l’asthme professionnel. Les éléments évocateurs sont la survenue de symptômes en période de travail et l’amélioration durant les congés. Ce dernier facteur a le meilleur niveau de preuve (grade 2+) lors de l’analyse de plusieurs publications selon les critères de médecine basés sur les preuves. L’étude du poste de travail est fondamentale, basée sur la coopération avec le médecin du travail. Des résultats positifs du bilan immunologique (tests cutanés et/ou recherche d’IgE spécifiques) associés à des critères objectifs de symptômes en relation avec le travail (modification du DEP, des EFR et/ou de l’HRBNS) permettent de préciser le diagnostic étiologique de l’asthme professionnel. Les tests de provocation bronchique spécifique nécessitant des équipes entraînées, apportent la preuve de la responsabilité de nouvelles substances et sont un recours nécessaire lorsque les autres investigations ne sont pas disponibles ou sont discordantes. L’asthme professionnel nécessite une démarche par étapes successives dans lesquelles peuvent également s’intégrer la recherche d’éosinophiles dans l’expectoration et la mesure du NO exhalé.
L’asthme professionnel nécessite une éviction du milieu du travail car la persistance de l’exposition peut entraîner une aggravation progressive de l’asthme et sa pérennisation. Cependant, l’éviction professionnelle a souvent des conséquences sociales et financières délétères, ce qui peut autoriser d’envisager un compromis avec une réduction de l’exposition par différents aménagements accompagnés d’un traitement adapté. Le traitement de l’asthme professionnel ne diffère pas de celui de l’asthme en général, il doit être ajusté selon les critères de gravité en utilisant bronchodilatateurs et corticoïdes. Sur le plan médico-légal, l’asthme professionnel peut être reconnu après déclaration en maladie professionnelle. En France, l’asthme est mentionné dans plusieurs tableaux de maladie professionnelle.
M.-C. Kopferschmitt-Kubler, E. Popin, G. Pauli
Occupational asthma (OA), with a latency period induced by multiple exposures, is characterized by immunological sensitization to the responsible agent, based on both an IgE mediated mechanisms and non specific bronchial hyper responsiveness.
In the diagnosis of OA, the medical history is obviously the starting-point. Onset of respiratory symptoms at work and resolution on vacation are indications of the diagnosis. After analysis of several publications, this element appears to have the best level of proof (grade 2+) according to the criteria of evidence-based medicine. A visit of the workplace, with the cooperation of the industrial physician, is essential to characterize the nature of the exposure. Positive immunological tests (skin tests and/or specific IgE) associated with objective criteria of symptoms related to work (modification of PEFR, lung function and/or nonspecific bronchial hyper responsiveness) will confirm the aetiological diagnosis of OA. Specific bronchial provocation tests performed in the laboratory allow the identification of new agents involved in OA and are necessary when other investigations are discordant or unavailable. OA needs a stepwise approach including induced sputum eosinophilic counts and measurements of exhaled nitric oxide.
requires removal from the workplace because persistence of exposure to respiratory sensitisers may lead to an increase and prolongation of asthma symptoms. However, removal from the workplace can have tremendous professional, financial and social consequences, and sometimes a compromise must be found with reduction of exposure by various methods combined with adequate treatment. The pharmacological treatment of patients with OA should be the same as for patients with non OA, the use of bronchodilators and corticoids depending on the severity of asthma. Concerning the medico-legal aspects, OA can be recognised as an occupational disease. In France OA is included in several tables of work-related diseases.

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^☆: From the Department of Chest Medicine, Hôpital du Sacré-Couer, Montreal. Dr. Malo is a research fellow with the Fonds de la Recherche en Santé du Québec and the Université de Montréal School of Medicine.

^☆☆: Supported in part by the Centre Québécois d’excellence en santé respiratoire.

^★: Reprint requests: Jean-Luc Malo, MD, Department of Chest Medicine, Hôpital du Sacré-Couer, 5400 W. Gouin, Montreal, Canada H4J 1C5.

^★★: 0091-6749/95 $5.00 + 0 1/1/64134

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Do subjects investigated for occupational asthma through serial peak expiratory flow measurements falsify their results?☆,☆☆,★,★★

Abstract

Section snippets

Subjects

RESULTS

DISCUSSION

Acknowledgements

Br J Dis Chest

J ALLERGY CLIN IMMUNOL

Chest

Respir Med

Daily peak flow measurements in the assessment of steroid therapy for airway obstruction

Br Med J

Peak flow rate records in the diagnosis of occupational asthma due to isocyanates

Thorax

Peak flow rate records in the diagnosis of occupational asthma due to colophony

Thorax

Physiologic assessment of occupational asthma

Occupational asthma: validity of monitoring of peak expiratory flow rates and non-allergic bronchial responsiveness as compared to specific inhalation challenge

Eur Respir J

How many times per day should peak expiratory flow rates be assessed when investigating occupational asthma?

Thorax