title: A Chronic Fatigue Syndrome (CFS) severity score based on case designation criteria.
abstract: BACKGROUND
  Chronic Fatigue Syndrome case designation criteria are scored as physicians' subjective, nominal interpretations of patient fatigue, pain (headaches, myalgia, arthralgia, sore throat and lymph nodes), cognitive dysfunction, sleep and exertional exhaustion.
  
  
  METHODS
  Subjects self-reported symptoms using an anchored ordinal scale of 0 (no symptom), 1 (trivial complaints), 2 (mild), 3 (moderate), and 4 (severe). Fatigue of 3 or 4 distinguished "Fatigued" from "Not Fatigued" subjects. The sum of the 8(Sum8) ancillary criteria was tested as a proxy for fatigue. All subjects had history and physical examinations to exclude medical fatigue, and ensure categorization as healthy or CFS subjects.
  
  
  RESULTS
  Fatigued subjects were divided into CFS with ≥4 symptoms or Chronic Idiopathic Fatigue (CIF) with ≤3 symptoms. ROC of Sum8 for CFS and Not Fatigued subjects generated a threshold of 14 (specificity=0.934; sensitivity=0.928). CFS (n=256) and CIF (n=55) criteria were refined to include Sum8≥14 and ≤13, respectively. Not Fatigued subjects had highly skewed Sum8 responses. Healthy Controls (HC; n=269) were defined by fatigue≤2 and Sum8≤13. Those with Sum8≥14 were defined as CFS-Like With Insufficient Fatigue Syndrome (CFSLWIFS; n=20). Sum8 and Fatigue were highly correlated (R(2)=0.977; Cronbach's alpha=0.924) indicating an intimate relationship between symptom constructs. Cluster analysis suggested 4 clades each in CFS and HC. Translational utility was inferred from the clustering of proteomics from cerebrospinal fluid.
  
  
  CONCLUSIONS
  Plotting Fatigue severity versus Sum8 produced an internally consistent classifying system. This is a necessary step for translating symptom profiles into fatigue phenotypes and their pathophysiological mechanisms.
authors: Division of Rheumatology, Immunology and Allergy, Georgetown University Washington, DC, USA.
authors: James N
authors: JN
authors: Baraniuk
authors: Oluwatoyin
authors: O
authors: Adewuyi
authors: Samantha Jean
authors: SJ
authors: Merck
authors: Mushtaq
authors: M
authors: Ali
authors: Murugan K
authors: MK
authors: Ravindran
authors: Christian R
authors: CR
authors: Timbol
authors: Rakib
authors: R
authors: Rayhan
authors: Yin
authors: Y
authors: Zheng
authors: Uyenphuong
authors: U
authors: Le
authors: Rania
authors: R
authors: Esteitie
authors: Kristina N
authors: KN
authors: Petrie
keywords: Fatigue; fibromyalgia; myalgic encephalomyelitis; pain; proteomics
references: Br J Gen Pract. 2003 Jun;53(491):441-5
references: 12939888
references: Psychol Med. 2005 Sep;35(9):1317-26
references: 16168154
references: Med Care. 1993 Mar;31(3):247-63
references: 8450681
references: Psychol Med. 2005 Sep;35(9):1337-48
references: 16168156
references: J Nerv Ment Dis. 2010 Jul;198(7):486-93
references: 20611051
references: PLoS One. 2011 Mar 30;6(3):e16872
references: 21479222
references: Arthritis Care Res (Hoboken). 2010 May;62(5):600-10
references: 20461783
references: J Clin Psychol Med Settings. 2011 Jun;18(2):155-63
references: 21626356
references: Psychiatry Res. 2011 Jul 30;188(2):245-52
references: 21600664
references: Cephalalgia. 2004;24 Suppl 1:9-160
references: 14979299
references: Biol Psychol. 2006 Aug;73(2):124-31
references: 16473456
references: Med Sci Sports Exerc. 2003 Jun;35(6):908-13
references: 12783037
references: BMC Neurol. 2005 Dec 01;5:22
references: 16321154
references: J Clin Psychol. 2012 Jan;68(1):41-9
references: 21823124
references: Neuropsychol Rev. 2005 Mar;15(1):29-58
references: 15929497
references: JAMA. 1998 Sep 16;280(11):981-8
references: 9749480
references: BMC Neurol. 2011 Mar 05;11:30
references: 21375763
references: Otolaryngol Head Neck Surg. 2002 Nov;127(5):387-97
references: 12447232
references: Toxicol Appl Pharmacol. 2010 Nov 1;248(3):285-92
references: 20430047
references: J Clin Pathol. 2007 Feb;60(2):117-9
references: 16935963
references: J Pain. 2009 Sep;10(9):895-926
references: 19712899
references: BMC Med. 2009 Oct 12;7:57
references: 19818157
references: Pharmacogenomics. 2006 Apr;7(3):429-40
references: 16610953
references: Popul Health Metr. 2007 Jun 08;5:5
references: 17559660
references: Ann Ist Super Sanita. 1999;35(3):435-41
references: 10721210
references: Arthritis Rheum. 1990 Feb;33(2):160-72
references: 2306288
references: Am J Respir Crit Care Med. 2005 Jan 1;171(1):5-11
references: 15477496
references: Behav Brain Funct. 2010 Dec 29;6:76
references: 21190576
references: BMC Med. 2011 Mar 21;9:26
references: 21418640
references: Ann Intern Med. 1994 Dec 15;121(12):953-9
references: 7978722
references: Injury. 2012 Dec;43(12):1990-5
references: 21855064
references: BMC Health Serv Res. 2003 Dec 31;3(1):25
references: 14702202
references: Pain. 1987 Aug;30(2):191-197
references: 3670870
references: J Allergy Clin Immunol. 1997 Jul;100(1):16-22
references: 9257782
references: NMR Biomed. 2011 Dec;24(10):1302-12
references: 21560176
references: Psychosom Med. 2003 Nov-Dec;65(6):1047-54
references: 14645784
references: Am J Med. 2007 Mar;120(3):e13
references: 17349421
references: N Engl J Med. 2011 Jun 2;364(22):2091-100
references: 21631321
references: Science. 2011 Jul 29;333(6042):517-9
references: 21798910
references: Med Care. 1992 Jun;30(6):473-83
references: 1593914
references: BMC Med. 2005 Dec 15;3:19
references: 16356178
references: J Sleep Res. 2008 Dec;17(4):427-31
references: 19021860
references: J Intern Med. 2011 Oct;270(4):327-38
references: 21777306
references: J Psychosom Res. 2005 Nov;59(5):283-90
references: 16253618
references: J Psychosom Res. 1995 Apr;39(3):315-25
references: 7636775
references: Am J Med. 1998 Sep 28;105(3A):83S-90S
references: 9790487
references: Ann Allergy Asthma Immunol. 1998 Oct;81(4):359-65
references: 9809501
references: J Asthma. 1999 Aug;36(5):459-65
references: 10461935
references: PLoS One. 2011 Feb 23;6(2):e17287
references: 21383843
references: Am J Epidemiol. 2000 Nov 15;152(10):992-1002
references: 11092441