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Table 1 Variables subjected to linear regression analyses among CFS patients

From: Relationship between autonomic cardiovascular control, case definition, clinical symptoms, and functional disability in adolescent chronic fatigue syndrome: an exploratory study

 

CFS-patients

Healthy controls * (n = 33)

 

Overall (n = 38)

CDC+ (n=27)

CDC– (n = 11)

 

Level 1, background and cardiovascular

Female gender

30 (79 %)

23 (85 %)

7 (64 %)

19 (58 %)

 

Mean (CI)

Mean (CI)

  

Age (years)

15

15

15

15

 

(14.4 to 15.5)

(14.2 to 15.7)

(14.2 to 16.0)

(14.5 to 15.8)

BMI (kg/m2)

22.3

22.3

22.2

20.6

 

(20.8 to 23.8)

(20.7 to 23.9)

(18.5 to 26.0)

(19.7 to 21.5)

Fatigue duration (months)

24

25

23

 
 

(20 to 28)

(19 to 30)

(18 to 28)

 

MAP baseline (mm Hg)**

82.2

83.1

79.8

80.0

 

(79.4 to 84.9)

(79.9 to 86.4)

(73.8 to 85.8)

(77.8 to 82.3)

HR baseline (beats/min)**

72.7

73.7

70.4

66.8

 

(68.9 to 76.6)

(68.9 to 78.5)

(63.0 to 77.7)

(63.2 to 70.4)

LF-RRI baseline (nu) **

38.3

37.2

40.9

40.8

 

(32.3 to 44.2)

(29.6 to 44.9)

(30.7 to 51.1)

(34.5 to 47.1)

HF-RRI baseline (nu) **

61.7

62.8

59.1

59.2

 

(55.8 to 67.7)

(55.1 to 70.4)

(48.9 to 69.3)

(52.9 to 65.5)

LF-RRI baseline (ms2) **

600

478

899

963

 

(331 to 868)

(280 to 677)

(29 to 1768)

(608 to 1318)

HF-RRI baseline (ms2) **

1120

1038

1319

1859

 

(700 to 1539)

(606 to 1470)

(186 to 2452)

(964 to 2753)

Delta MAP (mm Hg)**

5.4

4.3

7.8

−0.2

 

(3.8 to 6.9)

(2.6 to 6.1)

(4.8 to 10.9)

(−1.4 to 1.0)

Delta HR (beats/min)**

4.0

4.7

2.3

1.0

 

(2.3 to 5.7)

(2.5 to 6.8)

(−0.9 to 5.6)

(−0.3 to 2.3)

Delta LF-RRI (nu) **

8.4

8.7

7.8

−1.2

 

(3.8 to 13.1)

(2.6 to 14.7)

(0.3 to 15.4)

(−4.7 to 2.3)

Delta HF-RRI (nu) **

−8.4

−8.7

−7.8

1.2

 

(−13.1 to −3.8)

(−14.7 to −2.6)

(−15.4 to −0.3)

(−2.3 to 4.7)

Delta LF-RRI (ms2) **

−127

−16

−398

−262

 

(−329 to 76)

(−166 to 134)

(−1042 to 247)

(−446 to −77)

Delta HF-RRI (ms2) **

−372

−266

−632

−456

 

(−618 to −126)

(−458 to −74)

(−1412 to 147)

(−782 to −131)

Level 2, symptoms (1–5 scale)

Fatigue†

4.7

   
 

(4.5 to 4.8)

   

Cognitive alterations‡

3.1

   
 

(2.8 to 3.5)

   

Altered temperature control

3.0

   
 

(2.6 to 3.4)

   

Altered sleep

2.9

   
 

(2.3 to 3.4)

   

Hypersensitivity§

2.7

   
 

(2.3 to 3.1)

   

Paina

2.6

   
 

(2.3 to 3.0)

   

Altered peripheral circulationb

2.6

   
 

(2.2 to 3.1)

   

Altered central circulationc

2.5

   
 

(2.2 to 2.9)

   

Gastrointestinal alterations

2.4

   
 

(2.1 to 2.8)

   

Altered visual control

2.2

   
 

(1.7 to 2.7)

   

Immune alterationsd

1.6

   
 

(1.3 to 1.8)

   

Altered muscle control

1.6

   
 

(1.2 to 2.0)

   

Level 3, function (1–5 scale)

Disabilitye

2.9

   
 

(2.7 to 3.1)

   
  1. *Although not the aim of this article, reference values from healthy control subjects are displayed for clarity. Details concerning this reference material have been described elsewhere [7].**Obtained from 20o head up tilt test. †Fatigue severity scale [23]. ‡Mean of the following items: Difficult to concentrate; difficult to remember. §Mean of: Sensitivity towards sounds; sensitivity towards light. aMean of: Headache; muscle pain; joint pain. bMean of: Pale hands and feet; pale face. cMean of: Upright dizziness; palpitations. dMean of: Enlarged cervical lymph nodes; sensation of fever. eMean of: School attendance; homework; school physical activity; leisure activity; being with friends; being with family; going outdoors; getting up from bed.
  2. CI=confidence interval. CDC=Centers for disease control and prevention. CDC+ = adherence to CDC diagnostic criteria. CDC– = not adhering to CDC diagnostic criteria. BMI=body mass index. MAP=mean arterial pressure. HR=heart rate. LF-RRI=low-frequency variability of RR-interval (i.e. heart rate). HF-RRI=high-frequency variability of RR-interval (i.e. heart rate). n.u.=normalized units.
  3. In order to avoid the methodological problem of multiple testing, no statistical tests have been performed.