Khor Yet H, Gutman Lawrence, Abu Hussein Nebal, Johannson Kerri A, Glaspole Ian N, Guler Sabina A, Funke-Chambour Manuela, Geiser Thomas, Goh Nicole S L, Ryerson Christopher J
Department of Respiratory and Sleep Medicine/Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia; Faculty of Medicine, University of Melbourne, Melbourne, VIC, Australia; Department of Respiratory Medicine, Alfred Health, Melbourne, VIC, Australia; Centre for Heart Lung Innovation, Providence Health Care, Vancouver, BC, Canada.
Department of Medicine, University of Calgary, Calgary, AB, Canada.
Chest. 2021 Sep;160(3):994-1005. doi: 10.1016/j.chest.2021.04.037. Epub 2021 Apr 24.
Hypoxemia is a cardinal feature of fibrotic interstitial lung disease (ILD). The incidence, progression, and prognostic significance of hypoxemia in patients with fibrotic ILD currently is unknown.
What are the epidemiologic features of hypoxemia and its additive prognostic value in a current risk prediction model of fibrotic ILD?
We identified 848 patients with fibrotic ILD (258 with idiopathic pulmonary fibrosis [IPF]) in five prospective ILD registries from Australia, Canada, and Switzerland. Cumulative incidence of exertional and resting hypoxemia from the time of diagnosis was estimated at 1-year intervals in patients with baseline 6-min walk tests, adjusted for competing risks of death and lung transplantation. Likelihood ratio tests were used to determine the prognostic significance of exertional and resting hypoxemia for 1-year mortality or transplantation when added to the ILD-GAP model. The cohort was divided into derivation and validation subsets to evaluate performance characteristics of the extended model (the ILD-GAP-O model), which included oxygenation status as a predictor.
The 1-, 2-, and 5-year overall cumulative incidence was 6.1%, 17.3%, and 40.1%, respectively, for exertional hypoxemia and 2.4%, 5.6%, and 16.5%, respectively, for resting hypoxemia, which were significantly higher in patients with IPF compared with patients without IPF (P < .001 for both). Addition of exertional or resting hypoxemia to the ILD-GAP model improved 1-year mortality and transplantation prediction (P < .001 for both). The ILD-GAP-O model showed improved discrimination (C-index, 0.80 vs 0.75) and model fit (Akaike information criteria, 400 vs 422) in the validation cohort, with comparable calibration.
Patients with IPF have higher cumulative incidence of exertional and resting hypoxemia than patients without IPF. The extended ILD-GAP-O model provides additional risk stratification for 1-year prognosis in fibrotic ILD.
低氧血症是纤维化间质性肺疾病（ILD）的主要特征。目前，纤维化ILD患者低氧血症的发病率、进展情况及预后意义尚不清楚。
在当前纤维化ILD风险预测模型中，低氧血症的流行病学特征及其附加预后价值是什么？
我们从澳大利亚、加拿大和瑞士的五个前瞻性ILD登记处中，识别出848例纤维化ILD患者（258例特发性肺纤维化[IPF]患者）。对进行了基线6分钟步行试验的患者，每隔1年估计自诊断时起运动性和静息性低氧血症的累积发病率，并对死亡和肺移植的竞争风险进行校正。当将运动性和静息性低氧血症添加到ILD-GAP模型中时，使用似然比检验来确定其对1年死亡率或移植的预后意义。该队列被分为推导子集和验证子集，以评估扩展模型（ILD-GAP-O模型）的性能特征，该模型将氧合状态作为一个预测因素。
运动性低氧血症的1年、2年和5年总体累积发病率分别为6.1%、17.3%和40.1%，静息性低氧血症分别为2.4%、5.6%和16.5%，IPF患者的发病率显著高于非IPF患者（两者P均<0.001）。将运动性或静息性低氧血症添加到ILD-GAP模型中可改善1年死亡率和移植预测（两者P均<0.001）。ILD-GAP-O模型在验证队列中显示出更好的区分度（C指数，0.80对0.75）和模型拟合度（赤池信息准则，400对422），校准情况相当。
IPF患者运动性和静息性低氧血症的累积发病率高于非IPF患者。扩展的ILD-GAP-O模型为纤维化ILD的1年预后提供了额外的风险分层。
