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Table 4 Final cluster solution–differences in symptoms and functional abilities

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

Cluster

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)

p-valuea

CFQ-mean [95% CI]

18.9 [17.0, 20.9]

17.5 [13.8, 21.2]

18.6 [16.0, 21.1]

23.8 [19.0, 28.5]

20.7 [18.3, 23.1]

17.3 [10.2, 24.5]

0.344

PEM-mean (Mean Rank)

3.8 (47.9)

4.0 (56.6)

3.8 (48.1)

3.8 (n.a)

4.2 (59.0)

4.3 (n.a.)

0.074

MFQ-mean [95% CI]

18.1 [15.0, 21.2]

18.9 [10.6, 27.3]

14.7 [11.3, 18.0]

24.0 [12.5, 35.5]

17.9 [14.4, 21.4]

14.0 [-8.8, 36.8]

0.559

Steps per day-mean [95% CI]

5100 [4396, 5804]

5573 [3906, 7240]

4225 [3091, 5358]]

4015 [130, 7899]

3942 [3211, 4672]

3008 [1837, 4178]

0.063

FDI-mean [95% CI]

21.6 [19.2, 24.1]

19.7 [14.6, 24.7]

21.1 [17.2, 25.0]

28.8 [11.2, 46.3]

29.3 [25.8, 32.7]

21.0 [8.6, 33.4]

<0.001

PedsQL–mean [95% CI]

52.1 [48.5, 55.6]

51.7 [42.4, 60.9]

51.0 [44.6, 57.5]

44.0 [36.9, 51.1]

42.7 [38.2, 47.1]

44.5 [23.5, 65.6]

0.013

  1. HPA: hypothalamus–pituitary–adrenal; SD: standard deviation; CFQ: Chalder Fatigue Questionnaire; PEM: Post Exertional Malaise; MFQ: Moods and Feelings Questionnaire; FDI: Funtion and Disability Inventory; PedsQL: Pediatric Quality of Life. n.a.: not applicable.
  2. aUnadjusted p-values. The p-values are based on one-way ANOVA or Kruskal–Wallis test, as appropriate. Only group 1–3 and 5 were used in the statistical analyses due to few participants in group 4 and 6