Post W K, Venables K M, Ross D, Cullinan P, Heederik D, Burdorf A
Erasmus University, Department of Public Health, Rotterdam, The Netherlands.
Occup Environ Med. 1998 Feb;55(2):119-25. doi: 10.1136/oem.55.2.119.
Questionnaires, lung function tests, and peak flow measurements are widely used in occupational health care to screen for subjects with respiratory disease. However, the diagnostic performance of these tests is often poor. Application of these tests in a stepwise manner would presumably result in a better characterisation of subjects with respiratory disease.
Cross sectional data from workers exposed to acid anhydrides, to laboratory animals, and to flour dusts were used. Sensitivity and specificity were calculated from cross tables of different (combinations of) tests for bronchial hyperresponsiveness and bronchial irritability in the past four weeks (BIS). From sensitivity and specificity likelihood ratios were computed and change in probability of BIS was calculated.
The prevalence of BIS was 7%, 7%, and 5%, respectively. In all groups questionnaire data provided excellent sensitivity but poor specificity, which was inherent on the broad definition of symptoms. Adding the forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio yields almost perfect specificity, and peak expiratory flow (PEF) variability is intermediate in populations in which smoking induced or non-allergic respiratory diseases predominates. In occupational groups in which asthma is a problem, adding PEF measurements will optimise sensitivity and specificity in detection of BIS. The probability of BIS for subjects with a negative combined test outcome was lower than the probability before testing. Subjects with a positive combined test outcome had a probability of BIS after the tests at least three times the probability before.
Combined testing yields better sensitivity and specificity. An advantage of combined testing is an economy in the effort to screen for subjects with BIS. Combined testing resulted in more detailed estimation of the probability of BIS.
问卷调查、肺功能测试和呼气峰值流量测量在职业卫生保健中被广泛用于筛查呼吸系统疾病患者。然而，这些测试的诊断性能往往较差。以逐步方式应用这些测试可能会更好地对呼吸系统疾病患者进行特征描述。
使用了来自接触酸酐、实验动物和面粉粉尘的工人的横断面数据。根据过去四周支气管高反应性和支气管激惹性（BIS）的不同（组合）测试的交叉表计算敏感性和特异性。从敏感性和特异性计算似然比，并计算BIS概率的变化。
BIS的患病率分别为7%、7%和5%。在所有组中，问卷数据提供了出色的敏感性，但特异性较差，这是症状宽泛定义所固有的。加上一秒用力呼气量/用力肺活量（FEV1/FVC）比值可产生几乎完美的特异性，而呼气峰值流量（PEF）变异性在吸烟引起的或非过敏性呼吸系统疾病占主导的人群中处于中等水平。在哮喘成问题的职业群体中，增加PEF测量将优化检测BIS的敏感性和特异性。联合测试结果为阴性的受试者发生BIS的概率低于测试前的概率。联合测试结果为阳性的受试者在测试后发生BIS的概率至少是测试前的三倍。
联合测试产生更好的敏感性和特异性。联合测试的一个优点是在筛查BIS患者方面节省了精力。联合测试导致对BIS概率的更详细估计。
