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Table 1 Baseline demographic and clinical characteristics of the study participants

From: Association of circulating biomarkers with illness severity measures differentiates myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 condition: a prospective pilot cohort study

Variables

ME/CFS

Long COVID

Healthy controls

P-value 1

P-value 2

(n = 31)

(n = 23)

(n = 31)

Age, years

49.3 ± 3.1

48.7 ± 2.4

41.7 ± 1.8

n.s.

n.s.

Female, n (%)

20 (65)

15 (65)

22 (71)

n.s.

n.s.

BMI, kg/m2

25.5 ± 0.6

25.8 ± 0.9

24.2 ± 0.6

n.s.

n.s.

Illness duration at the inclusion time, years

7.4 ± 0.7

2.1 ± 0.6

n/a

n/a

n/a

SBP, mmHg

128.1 ± 3.1

124.6 ± 2.9

115.6 ± 2.0

< 0.0001

0.0038

DBP, mmHg

81.8 ± 1.5

77.8 ± 1.3

71.4 ± 1.4

< 0.0001

0.0006

HR, bpm

73.6 ± 1.8

67.2 ± 2.2

65.5 ± 1.7

0.0036

n.s.

Self-reported symptoms, n (%)

     

Post-exertional malaise

25 (80)

23 (100)

0 (0)

< 0.0001

< 0.0001

Cognitive impairments

6 (19)

23 (100)

0 (0)

0.024

< 0.0001

Unrefreshing sleep

22 (70)

20 (87)

0 (0)

< 0.0001

< 0.0001

Headache

5 (16)

17 (74)

0 (0)

0.050

< 0.0001

Anxiety/depression

10 (32)

6 (26)

0 (0)

0.0008

0.004

Gastrointestinal disturbances

10 (32)

14 (61)

0 (0)

0.0008

< 0.0001

Orthostatic intolerance

10 (32)

6 (26)

0 (0)

0.0008

0.004

Pre-existing comorbidities, n (%)

     

Fibromyalgia

13 (41)

7 (30)

0 (0)

< 0.0001

0.0014

Hypertension

7 (22)

5 (22)

0 (0)

0.011

0.011

IBS

4 (12)

4 (17)

0 (0)

0.017

0.028

Hypothyroidism

4 (12)

0 (0)

0 (0)

< 0.0001

n.s.

Dyslipidemia

4 (12)

4 (17)

0 (0)

n.s.

0.028

Diabetes

4 (12)

3 (13)

1 (3)

n.s.

n.s.

Cardiovascular disease

0 (0)

5 (22)

0 (0)

n.s.

0.011

Cerebrovascular disorder

0 (0)

0 (0)

0 (0)

n.s.

n.s.

Chronic COPD/asthma

4 (12)

1 (4)

0 (0)

n.s.

n.s.

CKD

0 (0)

1 (4)

0 (0)

n.s.

n.s.

COVID-19 status, n (%)

     

At home

14 (45)

4 (17)

5 (16)

0.026

n.s.

Outpatients

1 (3)

14 (61)

5 (16)

n.s.

0.0012

Hospitalized

0 (0)

5 (22)

0 (0)

n.s.

0.011

COVID-19 wave, n (%)a

     

Wave 1

20 (65)

19 (83)

0 (0)

< 0.0001

< 0.0001

Wave 2

6 (19)

4 (17)

5 (16)

n.s.

n.s.

Wave 3

3 (9)

0 (0)

7 (23)

n.s.

0.016

Vaccination status, n (%)b

     

None dose

1 (3)

1 (4)

0 (0)

n.s.

n.s.

One dose

30 (96)

22 (96)

31 (100)

n.s.

n.s.

Two doses

30 (96)

16 (70)

30 (96)

n.s.

0.0078

Three or more doses

19 (61)

8 (35)

22 (70)

n.s.

0.013

Vaccine type, n (%)

     

Pfizer

20 (64)

17(74)

24 (77)

n.s.

n.s.

Oxford

5 (16)

4 (17)

5 (16)

n.s.

n.s.

Moderna

4 (12)

1 (4)

2 (7)

n.s.

n.s.

Janssen

1 (3)

0 (0)

0 (0)

n.s.

n.s.

COVID-19 severityc

     

Asymptomatic

20 (64)

5 (22)

29 (94)

0.011

< 0.0001

Mild/moderate

10 (32)

18 (78)

2 (6)

0.022

< 0.0001

Severe

1(4)

0 (0)

0 (0)

n.s.

n.s.

Critically severe

0 (0)

0 (0)

0 (0)

n.s.

n.s.

Measuresd

     

FIS-40

     

Global score (0-160)

130.3 ± 3.3

127.5 ± 3.6

17.2 ± 2.6

< 0.0001

< 0.0001

 Physical

34.2 ± 0.8

33.3 ± 1.0

5.1 ± 0.7

< 0.0001

< 0.0001

 Cognitive

61.3 ± 2.0

59.1 ± 2.2

8.0 ± 1.3

< 0.0001

< 0.0001

 Psychosocial

34.8 ± 0.9

35.2 ± 1.0

4.1 ± 0.7

< 0.0001

< 0.0001

PSQI

     

Global score (0–21)

14.8 ± 0.7

14.0 ± 0.9

5.6 ± 0.4

< 0.0001

< 0.0001

 Subjective sleep quality

2.2 ± 0.1

2.2 ± 0.1

0.7 ± 0.1

< 0.0001

< 0.0001

 Sleep latency

2.1 ± 0.2

2.2 ± 0.2

1.3 ± 0.1

< 0.0001

0.0003

 Sleep duration

1.9 ± 0.1

1.8 ± 0.2

1.2 ± 0.1

< 0.0001

0.0003

 Habitual sleep efficiency

2.1 ± 0.2

1.8 ± 0.3

0.5 ± 0.1

< 0.0001

< 0.0001

 Sleep disturbances

2.3 ± 0.1

2.0 ± 0.1

1.0 ± 0.04

< 0.0001

< 0.0001

 Use of sleeping medication

2.0 ± 0.2

1.8 ± 0.3

0.3 ± 0.09

< 0.0001

< 0.0001

 Daytime dysfunction

2.24 ± 0.1

2.1 ± 0.2

0.6 ± 0.08

< 0.0001

< 0.0001

HADS

     

Global score (0–42)

24.8 ± 1.2

22.5 ± 1.7

6.5 ± 0.6

< 0.0001

< 0.0001

 Anxiety

12.9 ± 0.6

11.2 ± 1.0

4.7 ± 0.4

< 0.0001

< 0.0001

 Depression

11.9 ± 0.7

11.3 ± 0.9

1.8 ± 0.3

< 0.0001

< 0.0001

COMPASS-31

     

Global score (0-100)

56.0 ± 2.2

40.9 ± 3.7

11.8 ± 1.3

< 0.0001

< 0.0001

 Orthostatic intolerance

23.7 ± 1.2

17.2 ± 2.2

5.1 ± 0.8

< 0.0001

< 0.0001

 Vasomotor

1.7 ± 0.2

1.3 ± 0.3

0.08 ± 0.1

< 0.0001

< 0.0001

 Secretomotor

10.0 ± 0.5

7.5 ± 0.9

1.1 ± 0.3

< 0.0001

< 0.0001

 Gastrointestinal

12.4 ± 0.7

8.6 ± 1.0

4.0 ± 0.5

< 0.0001

< 0.0001

 Bladder

4.4 ± 0.5

3.5 ± 0.8

0.5 ± 0.1

< 0.0001

< 0.0001

 Pupillomotor

3.8 ± 0.2

2.6 ± 0.2

1.0 ± 0.1

< 0.0001

< 0.0001

OGS

     

Global score (0–20)

12.8 ± 0.9

10.6 ± 1.0

0.9 ± 0.3

< 0.0001

< 0.0001

 Frequency of orthostatic symptoms

2.7 ± 0.2

2.2 ± 0.2

0.3 ± 0.1

< 0.0001

< 0.0001

 Severity of orthostatic symptoms

2.6 ± 0.2

2.3 ± 0.2

0.3 ± 0.07

< 0.0001

< 0.0001

 Conditions under which orthostatic symptoms occur

2.7 ± 0.2

2.0 ± 0.2

0.2 ± 0.07

< 0.0001

< 0.0001

 Activities of daily living

2.5 ± 0.2

2.3 ± 0.3

0.02 ± 0.02

< 0.0001

< 0.0001

 Standing time

2.3 ± 0.3

1.7 ± 0.2

0.12 ± 0.08

< 0.0001

< 0.0001

SF-36

     

Global score (0-100)

27.0 ± 2.2

29.1 ± 3.0

86.9 ± 1.5

< 0.0001

< 0.0001

 Physical functioning

34.3 ± 3.2

44.8 ± 5.6

97.1 ± 0.7

< 0.0001

< 0.0001

 Physical role functioning

2.4 ± 1.5

1.1 ± 1.1

92.1 ± 2.5

< 0.0001

< 0.0001

 Bodily pain

18.3 ± 2.4

29.6 ± 4.5

86.2 ± 2.4

< 0.0001

< 0.0001

 General health perception

21.7 ± 2.4

27.8 ± 2.9

86.7 ± 1.5

< 0.0001

< 0.0001

 Vitality

14.0 ± 2.7

20.0 ± 3.9

71.7 ± 2.3

< 0.0001

< 0.0001

 Social role functioning

32.6 ± 3.6

33.4 ± 5.0

94.0 ± 1.8

< 0.0001

< 0.0001

 Emotional role functioning

46.3 ± 6.9

34.8 ± 9.7

90.6 ± 3.2

< 0.0001

< 0.0001

 Mental health

18.2 ± 2.5

44.6 ± 6.8

95.2 ± 3.4

< 0.0001

< 0.0001

 Physical health component summary scores (PCS)

36.1 ± 3.7

21.2 ± 4.6

76.4 ± 2.2

< 0.0001

< 0.0001

 Mental health component summary scores (MCS)

7.8 ± 3.1

11.2 ± 2.8

69.3 ± 2.6

< 0.0001

< 0.0001

  1. Data are presented as mean ± standard error of the mean (SEM) or number of participants (percentages), unless otherwise indicated. P-values were calculated by Mann-Whitney U-tests for continuous variables and from Fisher’s exact test for categorical variables. Bold values denote statistical significance at P ≤ 0.05 between cohorts. Superscripts (1) and (2) are the P-values for ME/CFS vs. healthy controls and Long COVID vs. healthy controls, respectively. a First wave of the COVID-19 epidemic in Spain lasted from February 2020 to September 2020 (original wild-type variant), second wave runs from October 2020 to July 2021 (alpha variant), and three wave is from August 2021 to July 2022 (delta/omicron variants). b The average periods of the vaccine administration were January 2021 (first dose), February 2021 (second dose), and November 2021 (third dose). c The SARS-CoV-2 infection (COVID-19) severity was defined based on the 2021 NIH/CDC COVID-19 treatment guidelines (available at https://www.covid19treatmentguidelines.nih.gov/; accessed on 15 June 2023). d Baseline self-reported outcome measures of symptoms (global and domain scores), as explained in the Methods section. n/a not applicable, n.s. not significant
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Journal of Translational Medicine

ISSN: 1479-5876

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