随着时间的推移,IPF患者出现进行性呼吸困难和肺功能下降。中位生存期估计为诊断后2~5年,大多数患者因疾病死亡。[82]Martinez FJ, Safrin S, Weycker D, et al. The clinical course of patients with idiopathic pulmonary fibrosis. Ann Intern Med. 2005;142:963-967.http://www.ncbi.nlm.nih.gov/pubmed/15968010?tool=bestpractice.com[88]Kim DS, Collard HR, King TE Jr. Classification and natural history of the idiopathic interstitial pneumonias. Proc Am Thorac Soc. 2006;3:285-292.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658683/http://www.ncbi.nlm.nih.gov/pubmed/16738191?tool=bestpractice.com临床恶化的过程具有异质性,有些患者进展迅速,有些进展缓慢,其余的患者仅在急性临床恶化(急性加重期)时肺功能下降。IPF患者急性加重的年发病率没有很好地描述,估计范围是5%~19%。这些患者的病死率高达49%~78%。[88]Kim DS, Collard HR, King TE Jr. Classification and natural history of the idiopathic interstitial pneumonias. Proc Am Thorac Soc. 2006;3:285-292.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658683/http://www.ncbi.nlm.nih.gov/pubmed/16738191?tool=bestpractice.com
最近提出一个新的分期系统,尚未在临床上常规应用。[89]Ley B, Ryerson CJ, Vittinghoff E, et al. A multidimensional index and staging system for idiopathic pulmonary fibrosis. Ann Intern Med. 2012;156:684-691.http://www.ncbi.nlm.nih.gov/pubmed/22586007?tool=bestpractice.com诊断时,根据性别、年龄和两项生理指标:FVC和肺一氧化碳弥散量(DLCO),计算“GAP”指数和分期系统,将患者分为3期。病死率随着分期进展而增加。作者还描述了一个“GAP计算器”,虽然更为复杂,但是提供了一个更为精确的风险评估方法。除了预测IPF的风险,GAP模型已经在慢性间质性肺疾病其他亚型中得到验证。[90]Ryerson CJ, Vittinghoff E, Ley B, et al. Predicting survival across chronic interstitial lung disease: the ILD-GAP model. Chest. 2014;145:723-728.http://www.ncbi.nlm.nih.gov/pubmed/24114524?tool=bestpractice.com随着时间的推移,GAP指数、分期系统和计算器在临床实践中的应用将更为普遍。
好的预后因素
IPF中HRCT呈“不典型”的类型,在诊断后的6个月里FVC和(或)肺弥散量保持稳定或改善,而矛盾之处是吸烟者与预后良好相关。[91]Flaherty KR, Thwaite EL, Kazerooni EA, et al. Radiological versus histological diagnosis in UIP and NSIP: survival implications. Thorax. 2003;58:143-148.http://thorax.bmj.com/content/58/2/143.longhttp://www.ncbi.nlm.nih.gov/pubmed/12554898?tool=bestpractice.com[92]Collard HR, King TE Jr, Bartelson BB, et al. Changes in clinical and physiologic variables predict survival in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med. 2003;168:538-542.http://www.atsjournals.org/doi/full/10.1164/rccm.200211-1311OC#.UmERpNglgZkhttp://www.ncbi.nlm.nih.gov/pubmed/12773325?tool=bestpractice.com[93]Latsi PI, du Bois RM, Nicholson AG, et al. Fibrotic idiopathic interstitial pneumonia. The prognostic value of longitudinal functional trends. Am J Respir Crit Care Med. 2003;168:531-537.http://www.atsjournals.org/doi/full/10.1164/rccm.200210-1245OC#.UmERetglgZkhttp://www.ncbi.nlm.nih.gov/pubmed/12791580?tool=bestpractice.com[94]Flaherty KR, Mumford JA, Murray S, et al. Prognostic implications of physiologic and radiographic changes in idiopathic interstitial pneumonia. Am J Respir Crit Care Med. 2003;168:543-548.http://www.atsjournals.org/doi/full/10.1164/rccm.200209-1112OC#.UmERTNglgZkhttp://www.ncbi.nlm.nih.gov/pubmed/12773329?tool=bestpractice.com[95]King TE Jr, Tooze JA, Schwarz MI, et al. Predicting survival in idiopathic pulmonary fibrosis: scoring system and survival model. Am J Respir Crit Care Med. 2001;164:1171-1181.http://www.atsjournals.org/doi/full/10.1164/ajrccm.164.7.2003140#.UmEQ-9glgZkhttp://www.ncbi.nlm.nih.gov/pubmed/11673205?tool=bestpractice.com吸烟的影响可能与目前吸烟者表现出的疾病严重程度的差异有关。[96]Antoniou KM, Hansell DM, Rubens MB, et al. Idiopathic pulmonary fibrosis: outcome in relation to smoking status. Am J Resp Crit Care Med. 2008;177:190-194.http://www.ncbi.nlm.nih.gov/pubmed/17962635?tool=bestpractice.com
预后不良的因素
提示不良预后的因素包括高龄、男性、肺功能中FVC和肺弥散量降低的严重程度、肺活检中成纤维细胞灶的数量增加、6分钟步行试验早期氧合血红蛋白的下降、运动后心率恢复障碍、诊断后最初的6~12月FVC的降低,以及急性加重。[45]Song JW, Hong SB, Lim CM, et al. Acute exacerbation of idiopathic pulmonary fibrosis: incidence, risk factors, and outcome. Eur Respir J. 2011;37:356-363.http://www.ncbi.nlm.nih.gov/pubmed/20595144?tool=bestpractice.com[88]Kim DS, Collard HR, King TE Jr. Classification and natural history of the idiopathic interstitial pneumonias. Proc Am Thorac Soc. 2006;3:285-292.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658683/http://www.ncbi.nlm.nih.gov/pubmed/16738191?tool=bestpractice.com[92]Collard HR, King TE Jr, Bartelson BB, et al. Changes in clinical and physiologic variables predict survival in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med. 2003;168:538-542.http://www.atsjournals.org/doi/full/10.1164/rccm.200211-1311OC#.UmERpNglgZkhttp://www.ncbi.nlm.nih.gov/pubmed/12773325?tool=bestpractice.com[94]Flaherty KR, Mumford JA, Murray S, et al. Prognostic implications of physiologic and radiographic changes in idiopathic interstitial pneumonia. Am J Respir Crit Care Med. 2003;168:543-548.http://www.atsjournals.org/doi/full/10.1164/rccm.200209-1112OC#.UmERTNglgZkhttp://www.ncbi.nlm.nih.gov/pubmed/12773329?tool=bestpractice.com[97]Zappala CJ, Latsi PI, Nicholson AG, et al. Marginal decline in forced vital capacity is associated with a poor outcome in idiopathic pulmonary fibrosis.
Eur Respir J. 2010;35:830-836.http://www.ncbi.nlm.nih.gov/pubmed/19840957?tool=bestpractice.com[98]Swigris JJ, Swick J, Wamboldt FS, et al. Heart rate recovery after 6-min walk test predicts survival in patients with idiopathic pulmonary fibrosis. Chest. 2009;136:841-848.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2775995/?tool=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19395579?tool=bestpractice.com[99]Lama VN, Flaherty KR, Toews GB, et al. Prognostic value of desaturation during a 6-minute walk test in idiopathic interstitial pneumonia. Am J Respir Crit Care Med. 2003;168:1084-1090.http://www.atsjournals.org/doi/full/10.1164/rccm.200302-219OC#.UmESG9glgZkhttp://www.ncbi.nlm.nih.gov/pubmed/12917227?tool=bestpractice.com
多项生物标志物有助于对预后的评估,但是这些生物标志物的临床价值尚不清楚。[40]Peljto AL, Zhang Y, Fingerlin TE, et al. Association between the MUC5B promoter polymorphism and survival in patients with idiopathic pulmonary fibrosis. JAMA. 2013;309:2232-2239.http://www.ncbi.nlm.nih.gov/pubmed/23695349?tool=bestpractice.com[100]Song JW, Do KH, Jang SJ, et al. Blood biomarkers MMP-7 and SP-A: predictors of outcome in idiopathic pulmonary fibrosis. Chest. 2013;143:1422-1429.http://www.ncbi.nlm.nih.gov/pubmed/23715088?tool=bestpractice.com[101]Nathan SD, Reffett T, Brown AW, et al. The red cell distribution width as a prognostic indicator in idiopathic pulmonary fibrosis. Chest. 2013;143:1692-1698.http://www.ncbi.nlm.nih.gov/pubmed/23238641?tool=bestpractice.com[102]Kahloon RA, Xue J, Bhargava A, et al. Patients with idiopathic pulmonary fibrosis with antibodies to heat shock protein 70 have poor prognoses. Am J Respir Crit Care Med. 2013;187:768-775.http://www.ncbi.nlm.nih.gov/pubmed/23262513?tool=bestpractice.com