Takei Reoto, Yamano Yasuhiko, Kataoka Kensuke, Yokoyama Toshiki, Matsuda Toshiaki, Kimura Tomoki, Furukawa Taiki, Takahashi Osamu, Chiba Hirofumi, Takahashi Hiroki, Kondoh Yasuhiro
Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
Department of Medical IT Center, Nagoya University Hospital, Japan; Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Japan.
Respir Investig. 2020 May;58(3):190-195. doi: 10.1016/j.resinv.2019.12.010. Epub 2020 Mar 8.
In Japan, the severity staging system for idiopathic pulmonary fibrosis (IPF) has been used to determine medical care subsidies. However, this system requires invasive procedures to measure arterial oxygen tension. Recently, noninvasive and simple measurements of oxygen saturation by pulse oximetry (SpO) have been used for severity assessments. We propose a pulse oximetry saturation (POS) staging system consisting of SpO parameters to predict prognosis.
We developed four prototype staging systems based on SpO at rest and desaturation, and adopted the system with the highest C-statistic as the POS staging system. The cutoff SpO values at rest were 96% and 90%, and desaturation was defined as SpO < 90% at the end of the 6-min-walk test.
Two-hundred and nineteen IPF patients were studied and the C-statistic values of models 1, 2, 3, and 4 were 0.633, 0.643, 0.630, and 0.673, respectively. We judged model 4 to be a superior POS staging system; it defined SpO ≥ 96% at rest without desaturation as stage Ⅰ; SpO ≥ 96% at rest with desaturation or SpO 90%-95% at rest without desaturation as stage Ⅱ; and SpO 90%-95% at rest with desaturation or SpO < 90% at rest as stage Ⅲ. The hazard ratios of POS stage Ⅰ, Ⅱ, and Ⅲ were 1.00, 2.25, and 4.99, respectively. The C-statistic of the POS staging system produced from 1000 bootstrap samples was similar (0.673), suggesting good internal validation.
A noninvasive and simple POS staging system defined by SpO can easily predict prognosis.
在日本，特发性肺纤维化（IPF）严重程度分期系统一直用于确定医疗护理补贴。然而，该系统需要通过侵入性操作来测量动脉血氧张力。最近，通过脉搏血氧饱和度仪（SpO）进行的无创且简单的血氧饱和度测量已用于严重程度评估。我们提出了一种由SpO参数组成的脉搏血氧饱和度（POS）分期系统来预测预后。
我们基于静息SpO和血氧饱和度下降情况开发了四个原型分期系统，并采用C统计量最高的系统作为POS分期系统。静息时的SpO截止值为96%和90%，血氧饱和度下降定义为6分钟步行试验结束时SpO<90%。
对219例IPF患者进行了研究，模型1、2、3和4的C统计量值分别为0.633、0.643、0.630和0.673。我们判定模型4为 superior POS分期系统；它将静息时SpO≥96%且无血氧饱和度下降定义为Ⅰ期；静息时SpO≥96%且有血氧饱和度下降或静息时SpO为90%-95%且无血氧饱和度下降定义为Ⅱ期；静息时SpO为90%-95%且有血氧饱和度下降或静息时SpO<90%定义为Ⅲ期。POSⅠ期、Ⅱ期和Ⅲ期的风险比分别为1.00、2.25和4.99。由1000个自抽样样本得出的POS分期系统的C统计量相似（0.673），表明内部验证良好。
由SpO定义的无创且简单的POS分期系统能够轻松预测预后。
