Division of Rheumatology, Jewish General Hospital, Room A-725, 3755 Cote Ste Catherine Road, Montreal, QC, Canada, H3T 1E2,
Clin Rheumatol. 2013 Oct;32(10):1467-74. doi: 10.1007/s10067-013-2301-8. Epub 2013 Jun 4.
In systemic sclerosis (SSc), impaired diffusing capacity for carbon monoxide (DLCO) can indicate interstitial lung disease (ILD), pulmonary hypertension (PH), and/or other disease manifestations, including anemia. We undertook this study to compare the various measures of DLCO in the setting of a complex disease like SSc. We analyzed the pulmonary function tests of a cohort of SSc subjects, as a whole and among subjects with isolated PH and ILD separately. Associations were assessed using Spearman correlation coefficients, Student's t tests, and F tests by one-way ANOVA. P values <0.05 were considered statistically significant. This study included 225 subjects (mean age, 57 years; 88 % women; mean disease duration, 9.6 years; 32 % with diffuse disease, 44 % with ILD, and 17 % with PH). Mean percent predicted DLCO values were 75 % for DLCOsb and 83 % for DLCOrb. Adjustment for alveolar volume (VA) resulted in near normalization of both DLCOsb/VAsb (91 %) and DLCOrb/VArb (91 %). Subjects with ILD had significantly lower DLCOsb but not DLCOsb/VAsb, whereas those with PH had significantly lower DLCOsb and DLCOsb/VAsb. Among the various measures of DLCO, DLCOsb had the strongest and most consistent associations with clinical outcomes of interest. Adjusting for alveolar volume dampened the associations except with PH, with which DLCOsb/VAsb was more strongly associated than DLCOsb. Low DLCOsb is the most sensitive measure to detect abnormalities in gas exchange in SSc but reflects both parenchymal lung disease and pulmonary vascular disease. Low DLCOsb/VAsb is more specific for pulmonary vascular disease and should be the preferred measure of gas exchange in SSc.
在系统性硬化症（SSc）中，一氧化碳弥散量（DLCO）降低可提示间质性肺病（ILD）、肺动脉高压（PH）和/或其他疾病表现，包括贫血。我们进行这项研究是为了比较在 SSc 等复杂疾病背景下不同的 DLCO 测量指标。我们分析了 SSc 患者队列的肺功能测试结果，包括整体和单独存在 PH 和 ILD 的患者。采用 Spearman 相关系数、学生 t 检验和单因素方差分析的 F 检验评估相关性。P 值<0.05 被认为具有统计学意义。这项研究共纳入了 225 名患者（平均年龄 57 岁，88%为女性，平均病程 9.6 年，32%为弥漫性疾病，44%为 ILD，17%为 PH）。DLCOsb 和 DLCOrb 的平均预计百分比分别为 75%和 83%。调整肺泡体积（VA）后，DLCOsb/VA（91%）和 DLCOrb/VArb（91%）接近正常。ILD 患者的 DLCOsb 显著降低，但 DLCOsb/VA 未降低，而 PH 患者的 DLCOsb 和 DLCOsb/VA 均显著降低。在各种 DLCO 测量指标中，DLCOsb 与我们关注的临床结局的相关性最强且最一致。调整肺泡体积后，除与 PH 相关的情况外，这些相关性减弱，DLCOsb/VA 与 PH 的相关性强于 DLCOsb。DLCOsb 降低是检测 SSc 中气体交换异常最敏感的指标，但反映了肺实质疾病和肺血管疾病。DLCOsb/VA 降低对肺血管疾病更特异，应作为 SSc 中气体交换的首选测量指标。
