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Table 2 Final cluster solution-contributing variables

From: Are there subgroups of chronic fatigue syndrome? An exploratory cluster analysis of biological markers

 

1: Pain tolerant & good cognitions (n = 40)

2: Restored HPA dynamics (n = 15)

3: Orthostatic intolerance (n = 20)

4: Low-grade inflammation (n = 4)

5: Pain intolerant & poor cognitions (n = 33)

6: High vagal activity (n = 3)

Plasma cortisol, nmol/L-mean (SD)

329 (118)

314 (132)

366 (132)

407 (136)

443 (154)

462 (169)

Urine cortisol:creatinine ratio, nmol/mmol-median (IQR)

3.2 (2.2, 4.4)

14.5 (7.0, 18.4)

3.2 (2.5, 4.9)

3.9 (2.8, 6.2)

3.2 (1.8, 4.4)

3.7 (n.a)

Interferon gamma, pg/mL-median (IQR)

84 (57, 119)

102 (63, 199)

125 (92, 250)

174 (79, 223)

65 (45, 116)

167 (n.a)

IP-10, pg/mL-median (IQR)

345 (261, 479)

419 (225, 467)

314 (323, 410)

2735 (2359, 3803)

313 (174, 502)

557 (n.a.)

HF-HRV supine, ms2-median (IQR)

1264 (422, 3262)

1743 (147, 2630)

869 (526, 2209)

101 (52, 126)

588 (198, 868)

11052 (n.a.)

Δ HR orthostatic response, beats/min-mean (SD)

3.5 (3.2)

2.5 (4.2)

9.9 (4.1)

3.9 (2.6)

4.7 (3.7)

7.8 (6.3)

Δ SI orthostatic response, mL/m2-mean (SD)

− 4.3 (2.9)

− 3.0 (5.6)

− 11.4 (4.1)

− 2.8 (5.4)

− 4.3 (3.3)

− 9.4 (5.0)

Pressure pain threshold, N/cm2-mean (SD)

20.1 (7.6)

16.5 (6.9)

15.2 (5.2)

13.2 (5.7)

9.8 (3.9)

17.1 (7.1)

Digit span forward, total score-mean (SD)

9.3 (2.1)

8.7 (1.5)

8.0 (2.1)

8.5 (2.4)

7.2 (1.2)

8.0 (1.0)

Color-Word interference test condition 2, sec-mean (SD)

25.7 (4.2)

22.9 (4.5)

25.9 (4.4)

25.3 (4.3)

30.2 (9.2)

23.7 (4.2)

  1. HPA: hypothalamus–pituitary–adrenal; CI: confidence interval; IP-10: Interferon gamma-induced protein 10; HR: heart rate; SI: stroke index; HF-HRV: high-frequency power of heart rate variability; IQR: interquartile range (25 and 75 percentile). Δ denotes the response (upright–supine) to orthostatic challenge. The characterizing variable scores within each cluster is highlighted with italics