纵向研究提示,17-64% 的患者经治疗得到改善;然而,低于 10% 的患者达到全面恢复标准,且高达 20% 的患者症状可能随着时间恶化。[260]Vercoulen JH, Swanink CM, Fennis JF, et al. Prognosis in chronic fatigue syndrome: a prospective study of the natural course. J Neurol Neurosurg Psychiatry. 1996 May;60(5):489-94.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC486359/http://www.ncbi.nlm.nih.gov/pubmed/8778251?tool=bestpractice.com[261]Ray C, Jefferies S, Weir WR. Coping and other predictors of outcome in chronic fatigue syndrome: A 1-year follow-up. J Psychosom Res. 1997 Oct;43(4):405-15.http://www.ncbi.nlm.nih.gov/pubmed/9330240?tool=bestpractice.com[262]Bonner D, Ron M, Chalder T, et al. Chronic fatigue syndrome: a follow-up study. J Neurol Neurosurg Psychiatry. 1994 May;57(5):617-21.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1072927/http://www.ncbi.nlm.nih.gov/pubmed/8201336?tool=bestpractice.com 重点是审查疲劳的严重程度以及这些研究中用于 CFS/ME 诊断的标准。一些纵向研究也表明,在传染性单核细胞增多症后出现 CFS/ME 的患者中,年轻患者的康复率高于年老患者,在疾病平均持续时间 11.4 年后超过 50% 的患者返回工作。[263]Nyland M, Naess H, Birkeland JS, et al. Longitudinal follow-up of employment status in patients with chronic fatigue syndrome after mononucleosis. BMJ Open. 2014 Nov 26;4(11):e005798.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4248085/http://www.ncbi.nlm.nih.gov/pubmed/25428629?tool=bestpractice.com 一项小型观察性研究的结果也显示,传染性单核细胞增多症后出现 CFS/ME 的青少年的缓解率高于成人的,也更易恢复至完全功能能力。[105]Katz BZ, Shiraishi Y, Mears CJ, et al. Chronic fatigue syndrome after infectious mononucleosis in adolescents. Pediatrics. 2009 Jul;124(1):189-93.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2756827/http://www.ncbi.nlm.nih.gov/pubmed/19564299?tool=bestpractice.com 相比之下,尽管经过标准治疗,但只有不足 10% 的无单核细胞增多症的 CFS/ME 患者恢复至发病前的功能水平。[105]Katz BZ, Shiraishi Y, Mears CJ, et al. Chronic fatigue syndrome after infectious mononucleosis in adolescents. Pediatrics. 2009 Jul;124(1):189-93.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2756827/http://www.ncbi.nlm.nih.gov/pubmed/19564299?tool=bestpractice.com 在单家三级转诊中心进行的一项研究发现,有突发疲劳、发热、淋巴结压痛和肌痛病史的感染后 CFS/ME 亚组患者,5 年内会有所改善。[264]Naess H, Sundal E, Myhr KM, et al. Postinfectious and chronic fatigue syndromes: clinical experience from a tertiary-referral centre in Norway. In Vivo. 2010 Mar-Apr;24(2):185-8.http://iv.iiarjournals.org/content/24/2/185.longhttp://www.ncbi.nlm.nih.gov/pubmed/20363992?tool=bestpractice.com 不良预后因素包括:关节痛、高龄、疾病持续时间较长、疲乏程度严重、有共患精神疾病(自述抑郁)以及造成 CFS/ME 的身体因素。[265]Joyce J, Hotopf M, Wessely S. The prognosis of chronic fatigue and chronic fatigue syndrome: a systematic review. QJM. 1997 Mar;90(3):223-33.http://qjmed.oxfordjournals.org/content/90/3/223.full.pdf+htmlhttp://www.ncbi.nlm.nih.gov/pubmed/9093600?tool=bestpractice.com
有关 CFS/ME 患者死亡率过高的证据有限且混杂。一项小型研究 (n = 56) 发现,与美国总体人群(中位年龄= 77.7 岁)相比,CFS/ME 患者发生心血管死亡的平均年龄较小(中位年龄= 58.8 岁)。[103]McManimen SL, Devendorf AR, Brown AA, et al. Mortality in patients with myalgic encephalomyelitis and chronic fatigue syndrome. Fatigue. 2016;4:195-207.http://www.ncbi.nlm.nih.gov/pubmed/28070451?tool=bestpractice.com 一项更大规模的回顾性队列研究 (n = 2147) 未发现全因死亡率增加,但确实显示自杀死亡风险显著增加。[104]Roberts E, Wessely S, Chalder T, et al. Mortality of people with chronic fatigue syndrome: a retrospective cohort study in England and Wales from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search (CRIS) Register. Lancet. 2016 Apr 16;387(10028):1638-43.http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2815%2901223-4/fulltexthttp://www.ncbi.nlm.nih.gov/pubmed/26873808?tool=bestpractice.com