BACKGROUND There is low diagnostic accuracy of the proxy restrictive spirometric pattern (RSP) to identify true pulmonary restriction. This knowledge is based on patients referred for spirometry and total lung volume determination by plethysmograpy, single breath nitrogen washout technique or gas dilution and selected controls. There is, however, a lack of data from general populations analyzing whether RSP is a valid proxy for true pulmonary restriction. We have validated RSP in relation to true pulmonary restriction in a general population where we have access to measurements of total lung capacity (TLC) and spirometry. METHODS The data was from the Swedish CArdioPulmonary bioImage Study (SCAPIS Pilot), a general population-based study, comprising 983 adults aged 50-64. All subjects answered a respiratory questionnaire. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were obtained before and after bronchodilation. TLC and residual volume (RV) was recorded using a body plethysmograph. All lung function values are generally expressed as percent predicted (% predicted) or in relation to lower limits of normal (LLN). True pulmonary restriction was defined as TLC < LLN5 defined as a Z score < - 1.645, i e the fifth percentile. RSP was defined as FEV1/FVC ≥ LLN and FVC < LLN after bronchodilation. Specificity, sensitivity, positive and negative likelihood ratios were calculated, and 95% confidence intervals (CIs) were calculated. RESULTS The prevalence of true pulmonary restriction was 5.4%, and the prevalence of RSP was 3.4%. The sensitivity of RSP to identify true pulmonary restriction was 0.34 (0.20-0.46), the corresponding specificity was 0.98 (0.97-0.99), and the positive likelihood ratio was 21.1 (11.3-39.4) and the negative likelihood ratio was 0.67 (0.55-0.81). CONCLUSIONS RSP has low accuracy for identifying true pulmonary restriction. The results support previous observations that RSP is useful for ruling out true pulmonary restriction.

中文翻译：

---

50 - 64 岁一般人群样本中的限制性肺量测定模式和真实肺限制。


背景技术用于识别真正的肺限制的代理限制性肺量测定模式（RSP）的诊断准确性较低。这些知识基于转诊进行肺活量测定的患者以及通过体积描记法、单次呼吸氮气冲洗技术或气体稀释和选定的对照来确定肺总量的患者。然而，缺乏来自一般人群的数据来分析 RSP 是否是真正肺限制的有效指标。我们已经在普通人群中验证了 RSP 与真实肺限制的关系，我们可以测量总肺活量 (TLC) 和肺活量测定法。方法 数据来自瑞典 CArdioPulmonary bioImage 研究 (SCAPIS Pilot)，这是一项基于一般人群的研究，包括 983 名 50-64 岁的成年人。所有受试者均回答了呼吸问卷。支气管扩张前后获得 1 秒用力呼气量 (FEV1) 和用力肺活量 (FVC)。使用身体体积描记器记录 TLC 和残余体积 (RV)。所有肺功能值通常表示为预测百分比（%预测）或与正常下限（LLN）的关系。真正的肺限制被定义为TLC< LLN5，定义为Z分数<-1.645，即第五个百分位。 RSP 定义为支气管扩张后 FEV1/FVC ≥ LLN 且 FVC < LLN。计算特异性、敏感性、阳性和阴性似然比，并计算 95% 置信区间 (CI)。结果真性肺限制的发生率为5.4%，RSP的发生率为3.4%。 RSP识别真正肺限制的敏感性为0.34（0.20-0.46），相应的特异性为0.98（0.97-0.99），阳性似然比为21.1（11.3-39）。4) 阴性似然比为 0.67 (0.55-0.81)。结论 RSP 识别真正肺部受限的准确性较低。结果支持了之前的观察结果，即 RSP 对于排除真正的肺限制很有用。