Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
Rehabilitation Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
BMJ Open Respir Res. 2020 Dec;7(1). doi: 10.1136/bmjresp-2020-000770.
Asthma is a common, heterogeneous disease that is characterised by chronic airway inflammation and variable expiratory airflow limitation. Current guidelines use spirometric measures for asthma assessment. This systematic review aimed to assess whether the most commonly reported tests of small airways function could contribute to the diagnosis of asthma.
Standard systematic review methodology was used, and a range of electronic databases was searched (Embase, MEDLINE, CINAHL, CENTRAL, Web of Science, DARE). Studies that included physiological tests of small airways function to diagnose asthma in adults were included, with no restrictions on language or date. The risk of bias and quality assessment tools used were Agency for Healthcare Research and Quality tool for cross-sectional studies and Quality Assessment of Diagnostic Accuracy Studies 2 for diagnostic test accuracy (DTA) studies.
7072 studies were identified and 10 studies met review criteria. 7 included oscillation techniques and 5 included maximal mid-expiratory flow (MMEF). Studies were small and of variable quality. In oscillometry, total resistance (R5) and reactance at 5 Hz (X5) was altered in asthma compared with healthy controls. The percentage predicted of MMEF was lower in patients with asthma compared with controls in all studies and lower than the % predicted forced expiratory volume in 1 s. In DTA of oscillometry, R5 showed a sensitivity between 69% and 72% and specificity between 61% and 86%.
There were differences in the results of physiological tests of small airway function in patients with asthma compared with controls. However, studies are small and heterogeneous. Further studies are needed to assess the effectiveness of these tests on a larger scale, including studies to determine which test methodology is the most useful in asthma.
哮喘是一种常见的异质性疾病，其特征为慢性气道炎症和可变的呼气气流受限。目前的指南使用肺量计测量来评估哮喘。本系统评价旨在评估最常报告的小气道功能测试是否有助于哮喘的诊断。
采用标准系统评价方法，检索了一系列电子数据库（Embase、MEDLINE、CINAHL、CENTRAL、Web of Science、DARE）。纳入了包括小气道功能生理测试以诊断成人哮喘的研究，语言和日期均无限制。使用的偏倚风险和质量评估工具为横断面研究的美国医疗保健研究与质量局工具和诊断准确性研究的质量评估 2 工具。
共确定了 7072 项研究，其中 10 项研究符合审查标准。其中 7 项研究包括振荡技术，5 项研究包括最大中期呼气流量（MMEF）。研究规模较小，质量参差不齐。在振荡测量中，与健康对照组相比，哮喘患者的总阻力（R5）和 5 Hz 电抗（X5）发生改变。与对照组相比，所有研究中哮喘患者的 MMEF 预测百分比均较低，且低于 1 秒用力呼气量的预测百分比。在振荡测量的诊断准确性研究中，R5 的敏感性在 69%至 72%之间，特异性在 61%至 86%之间。
与健康对照组相比，哮喘患者的小气道功能生理测试结果存在差异。然而，研究规模较小且存在异质性。需要进一步的研究来评估这些测试在更大范围内的有效性，包括确定哪种测试方法在哮喘中最有用的研究。
