A novel respiratory reactance index, frequency-dependent, and for effort-independent assessment of COPD severity using MostGraph

IF 3.3 3区医学 Q2 CARDIAC & CARDIOVASCULAR SYSTEMS

Respiratory medicine Pub Date : 2026-02-01 Epub Date: 2026-01-15 DOI:10.1016/j.rmed.2026.108656

Hiroyuki Tsuji , Sho Mitsuya , Kenjiro Tsuruoka , Takahiko Nakamura , Yosuke Tamura , Isao Goto , KyongYob Min , Soichiro Ikeda , Akihisa Imagawa , Yasuhito Fujisaka

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引用次数: 0

Abstract

Background

Oscillometry has gained attention as a respiratory function test that does not require patient effort, particularly in older individuals and in those with severe respiratory disease. Although spirometry is essential for classifying the severity of chronic obstructive pulmonary disease (COPD), it requires forced expiration, which may be difficult in frail patients. In COPD, the slope of the respiratory reactance curve measured by oscillometry changes. This study evaluated the usefulness of a novel index, [X5 × (Fres−5)]/ALX, which quantifies the frequency dependence of respiratory reactance using parameters measurable by oscillometry.

Methods

This retrospective observational study included patients with COPD who underwent spirometry and oscillometry at Osaka Medical and Pharmaceutical University Hospital between March 2014 and January 2020. X5, Fres, and ALX were measured using the MostGraph to calculate the novel index. Receiver operating characteristic (ROC) analysis was performed to assess diagnostic performance for detecting Global Initiative for Obstructive Lung Disease (GOLD) stage 3/4 COPD, including sex-specific evaluations.

Results

Based on chest CT findings, patients with lung cancer or interstitial lung disease were excluded, leaving 109 participants. The novel index demonstrated strong performance in identifying GOLD stage 3/4 COPD (AUC: 0.858; sensitivity: 81.0 %; specificity: 79.5 %), outperforming X5, Fres, and ALX individually. The AUCs were 0.874 in males and 0.914 in females. The index showed a moderate correlation with %FEV1 (r_s = 0.603).

Conclusion

The index [X5 × (Fres−5)]/ALX effectively reflects the frequency dependence of respiratory reactance and may serve as a useful, effort-independent tool for assessing COPD severity, particularly for identifying GOLD stage 3/4 disease.

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一种新的呼吸阻抗指数，依赖于频率，并使用MostGraph来评估COPD的严重程度。

背景：振荡测量法作为一种不需要患者努力的呼吸功能测试已经引起了人们的关注，特别是在老年人和患有严重呼吸系统疾病的患者中。虽然肺活量测定法对慢性阻塞性肺疾病（COPD）的严重程度进行分类是必不可少的，但它需要强制呼气，这在虚弱的患者中可能很困难。在慢性阻塞性肺病中，振荡法测量的呼吸电抗曲线斜率发生变化。本研究评估了一种新的指数[x5x (fre -5)]/ALX的有效性，该指数使用振荡法测量的参数量化呼吸电抗的频率依赖性。方法：这项回顾性观察性研究纳入了2014年3月至2020年1月在大阪医科大学医院接受肺活量测定和振荡测量的COPD患者。使用MostGraph测量X5、Fres和ALX以计算新指数。进行受试者工作特征（ROC）分析，以评估全球阻塞性肺疾病倡议（GOLD） 3/4期COPD的诊断性能，包括性别特异性评估。结果：根据胸部CT表现，排除肺癌或间质性肺疾病患者，留下109名参与者。该新指标在识别GOLD期3/4期COPD方面表现出色（AUC: 0.858，敏感性：81.0%，特异性：79.5%），优于X5、Fres和ALX。男性的auc为0.874，女性为0.914。该指数与%FEV1呈中等相关性（r_s = 0.603）。结论：指数[x5x (fre -5)]/ALX能有效反映呼吸阻抗的频率依赖性，可作为评估COPD严重程度的有用且不依赖于努力的工具，特别是用于识别GOLD 3/4期疾病。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Respiratory medicine 医学-呼吸系统

CiteScore

7.50

自引率

0.00%

发文量

199

审稿时长

38 days

期刊介绍： Respiratory Medicine is an internationally-renowned journal devoted to the rapid publication of clinically-relevant respiratory medicine research. It combines cutting-edge original research with state-of-the-art reviews dealing with all aspects of respiratory diseases and therapeutic interventions. Topics include adult and paediatric medicine, epidemiology, immunology and cell biology, physiology, occupational disorders, and the role of allergens and pollutants. Respiratory Medicine is increasingly the journal of choice for publication of phased trial work, commenting on effectiveness, dosage and methods of action.