Mahler D A, Harver A
Department of Medicine, Dartmouth Medical School, Hanover, New Hampshire 03756.
Am Rev Respir Dis. 1992 Feb;145(2 Pt 1):467-70. doi: 10.1164/ajrccm/145.2_Pt_1.467.
The purpose of this study was to demonstrate that clinical ratings of dyspnea and physiologic function are separate dimensions underlying the pathophysiology of chronic obstructive pulmonary disease (COPD). We used principal-components factor analysis to confirm these dimensions using data collected prospectively in 86 symptomatic patients with COPD. Three different instruments were used to rate dyspnea: a modified Medical Research Council (MRC) scale, the oxygen cost diagram (OCD), and the baseline dyspnea index (BDI). Measures of physiologic function included standard spirometric measures (forced vital capacity [FVC] and forced expiratory volume in one second [FEV1]) and maximal inspiratory (PImax) and expiratory (PEmax) mouth pressures. Age of the 65 male and 21 female subjects was 62.9 +/- 1.2 yr (mean +/- SEM). All three clinical scales were significantly correlated with physiologic function (range of r values, 0.32 to 0.45; p less than 0.05), except for the relationship between the MRC scale and PEmax (r = -0.14; p = NS). The factor analysis yielded three factors that accounted for 71.9% of the total variance of the data: clinical ratings of dyspnea (MRC scale, OCD, and BDI) loaded on the first factor; maximal respiratory pressures and gender loaded on the second factor; and lung function and age loaded on the third factor. Additional post hoc factor analysis provided similar results when the sample was divided into two subgroups by randomization, by severity of dyspnea ratings, or by severity of airflow obstruction. We conclude that dyspnea ratings, maximal respiratory pressures, and lung function are separate factors or quantities that independently characterize the condition of patients with COPD.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是证明呼吸困难的临床评分和生理功能是慢性阻塞性肺疾病（COPD）病理生理学的不同维度。我们使用主成分因子分析，利用前瞻性收集的86例有症状的COPD患者的数据来证实这些维度。使用三种不同的工具对呼吸困难进行评分：改良的医学研究委员会（MRC）量表、氧耗图（OCD）和基线呼吸困难指数（BDI）。生理功能的测量包括标准肺量计测量（用力肺活量[FVC]和一秒用力呼气量[FEV1]）以及最大吸气（PImax）和呼气（PEmax）口腔压力。65名男性和21名女性受试者的年龄为62.9±1.2岁（均值±标准误）。除MRC量表与PEmax之间的关系外（r = -0.14；p =无统计学意义），所有三种临床量表均与生理功能显著相关（r值范围为0.32至0.45；p＜0.05）。因子分析产生了三个因子，占数据总方差的71.9%：呼吸困难的临床评分（MRC量表、OCD和BDI）加载在第一个因子上；最大呼吸压力和性别加载在第二个因子上；肺功能和年龄加载在第三个因子上。当样本通过随机化、呼吸困难评分严重程度或气流阻塞严重程度分为两个亚组时，额外的事后因子分析提供了类似的结果。我们得出结论，呼吸困难评分、最大呼吸压力和肺功能是独立的因子或量，可独立表征COPD患者的病情。（摘要截断于250字）
