In Brazil, prevalence of diagnosed COPD among adults aged 40 years and over is 16% although over 70% of cases remain undiagnosed. Hypertension is common and well-recorded in primary care, and frequently co-exists with COPD because of common causes such as tobacco smoking, therefore we conducted a cross-sectional screening test accuracy study in nine Basic Health Units in Brazil, among hypertensive patients aged ≥40 years to identify the optimum screening test/combinations to detect undiagnosed COPD. We compared six index tests (four screening questionnaires, microspirometer and peak flow) against the reference test defined as those below the lower limit of normal (LLN-GLI) on quality diagnostic spirometry, with confirmed COPD at clinical review. Of 1162 participants, 6.8% (n = 79) had clinically confirmed COPD. Peak flow had a higher specificity but lower sensitivity than microspirometry (sensitivity 44.3% [95% CI 33.1, 55.9], specificity 95.5% [95% CI 94.1, 96.6]). SBQ performed well compared to the other questionnaires (sensitivity 75.9% [95% CI 65.0, 84.9], specificity 59.2% [95% CI 56.2, 62.1]). A strategy requiring both SBQ and peak flow to be positive yielded sensitivity of 39.2% (95% CI 28.4, 50.9) and specificity of 97.0% (95% CI 95.7, 97.9). The use of simple screening tests was feasible within the Brazilian primary care setting. The combination of SBQ and peak flow appeared most efficient, when considering performance of the test, cost and ease of use (costing £1690 (5554 R$) with 26.7 cases detected per 1,000 patients). However, the choice of screening tests depends on the clinical setting and availability of resources.

ISRCTN registration number: 11377960.

在巴西，40 岁及以上的成年人中确诊 COPD 的患病率为 16%，但仍有超过 70% 的病例未确诊。高血压在初级保健中很常见并且有很好的记录，并且由于吸烟等常见原因而经常与 COPD 共存，因此我们在巴西的九个基本卫生单位进行了一项横断面筛查测试准确性研究，对象是年龄较大的高血压患者≥40 年确定最佳筛查试验/组合以检测未确诊的 COPD。我们将六项指标测试（四项筛查问卷、显微肺活量计和峰值流量）与参考测试进行了比较，参考测试定义为质量诊断肺活量测定低于正常下限 (LLN-GLI) 的那些，并在临床审查中确认了 COPD。在 1162 名参与者中，6.8% ( n = 79) 患有临床确诊的 COPD。峰值流量比显微肺活量测定法具有更高的特异性，但灵敏度较低（灵敏度 44.3% [95% CI 33.1, 55.9]，特异性 95.5% [95% CI 94.1, 96.6]）。与其他问卷相比，SBQ 表现良好（灵敏度 75.9% [95% CI 65.0, 84.9]，特异性 59.2% [95% CI 56.2, 62.1]）。要求 SBQ 和峰值流量均为正值的策略产生的灵敏度为 39.2%（95% CI 28.4, 50.9），特异性为 97.0%（95% CI 95.7, 97.9）。在巴西的初级保健环境中使用简单的筛查测试是可行的。考虑到测试的性能、成本和易用性（每 1,000 名患者检测到 26.7 例，花费 1690 英镑（5554 雷亚尔），SBQ 和峰值流量的组合似乎最有效）。然而，

ISRCTN注册号：11377960。