Ngamjit Kongsupon, Peymane Adab, Rachel E Jordan, Christopher C Huntley, Siwanon Rattanakanokchai, Samuel Wallbanks, Shiyao Li, Gareth I Walters BMJ Open Respiratory Research 2025;12:e003251.
Abstract
Introduction
One in four cases of asthma in adults is caused or worsened by work (work-related asthma: WRA). Early detection of WRA could prevent poor health and employment outcomes, but clinical diagnosis is often missed or delayed. The standardisation and effectiveness of screening tools have not been well established. We aimed to summarise and compare the performance of screening tools for identifying WRA in both clinical settings and workplaces.
Methods
We searched for studies that used structured questionnaires or prediction models (with/without physiological tests) to identify WRA in clinical settings or workplaces with individuals aged≥16 years in MEDLINE, Embase, other bibliographic databases and grey literature between 1975 and 2024. Two reviewers independently screened titles, abstracts and full texts for inclusion, extracted data and assessed risk of bias using QUADAS-2 tool (Quality Assessment of Diagnostic Test Accuracy 2) or PROBAST (Prediction Model Risk of Bias Assessment Tool). Screening tools and their indices of accuracy were summarised with paired forest plots of sensitivities and specificities.
Results
Of 17 504 identified studies, 7 were included. All were implemented in tertiary hospitals (n=5) and specialist centres (n=2). The screening tools comprised questionnaires alone (individual questions n=3 and multiple questions n=2), questionnaire with methacholine challenge test (n=1) and diagnostic models (n=4). The question ‘improvement off work’ had sensitivity=74–87% and specificity=15–58% for identifying WRA. Multiple questions had sensitivity=80–100% and specificity=8–55%. Addition of the methacholine challenge test to one questionnaire improved specificity to 75% with sensitivity=65%. Diagnostic models reported area under the curve (AUC) between 0.69 and 0.89, and AUC was improved when adding demographic variables or objective tests.
Discussion
A single item ‘improvement off work’ and multiple questions have high sensitivity but low specificity for WRA, which are sufficient for screening purposes to enhance WRA diagnosis. Adding demographic variables and objective tests can improve specificity or AUC. However, studies on screening tools for WRA are limited and inadequately reported; further evaluations of performance are needed in primary care populations and workplaces.
What is already known on this topic
- Work-related asthma (WRA) is common, but underdiagnosed. If untreated, it can lead to significant morbidity and loss of work productivity, both of which could be prevented through earlier diagnosis.
- Screening tools are not standardised, and guidelines and recommendations are based on outdated evidence.
What this study adds
- Screening questionnaires and diagnostic models have been developed to detect WRA, but all were tested in specialist clinical settings.
- A single screening question regarding work-related symptom screening (improvement off work), or a combination of questions, has good sensitivity but low specificity in identifying WRA.
- The addition of objective tests to a questionnaire or diagnostic model improves specificity and the area under the curve of the tests.
How this study might affect research, practice or policy
- Asking about improvement of symptoms away from work is sufficient for screening purposes and should be included in asthma care clinics or workplace respiratory health surveillance to improve identifying the WRA.
- High-quality screening test accuracy studies conducted in primary care, general population and workplace settings are needed for better identification of WRA.