A Comparison between Venables Standardized Respiratory Questionnaire and Pre-Shift Spirometry in Screening of Occupational Asthma in a Steel Industry

Background: Occupational asthma (OA) is the most common occupational lung disease indeveloped countries. One of the causative agents is metal fume that may be encountered insteel industries. Screening for the OA is mainly performed by questionnaire but in our countryspirometry is used more commonlyObjective: To compare the diagnostic value of the Venables standardized respiratory questionnaireand pre-shift spirometry as screening tools for OAMethod: In a cross-sectional study, we investigated 450 workers of a steel industry bythe Venables standardized questionnaire. We also performed a pre-shift spirometry as thescreening spirometry and a post-shift spirometry. A person with 10% drop in post-shift FEV1compared with the pre-shift value was considered as asthmatic (our gold-standard). Theresults of the questionnaire and the pre-shift spirometry were then examined against thegold-standard test results. For each test, sensitivity, specificity, positive and negative predictivevalues were calculatedResults: The overall prevalence of OA among our studied workers was 3.9% (95% CI:1.9%–5.9%). The highest rate was seen in those working in catering (25%) and welding(10%) units. Pre-shift spirometry and the questionnaire had low sensitivity (42.9% and28.6%, respectively) and positive predictive values (16.7% and 3.6%, respectively); moderatespecificity (92.4% and 71.6%, respectively) and high negative predictive values (97.9%and 96.5%, respectively)Conclusion: Taking into account the ease of use of the questionnaire, it seems that it ismore feasible to use questionnaire as the primary screening tool for the diagnosis of OA