Table 1

Baseline characteristics

Patients with CFS, baselineDifference/OR95% CI of difference/ORP value
SEID-negative
(n=69)
SEID-positive
(n=45)
Gender, n (%)
 Male22 (32)10 (22)1.640.69 to 3.900.262
 Female47 (68)35 (78)
Age, years, mean (SD)15.5 (1.6)15.1 (1.6)−0.35−0.95 to 0.260.264
BMI, kg/m2, mean (SD)21.8 (3.9)21.2 (4.7)0.54−2.16 to 1.070.507
Disease duration, months, median (IQR)18 (17)15 (16)3−2 to 110.101
Symptoms suggesting a mood disorder, total score, mean (SD)13.4 (7.6)23.2 (10.8)9.195.78 to 12.6<0.001
Steps per day, number, mean (SD)4824 (2507)4342 (2276)−481−1409 to 4460.306
Chalder Fatigue Questionnaire, total score, mean (SD)18.1 (5.8)20.7 (6.0)2.670.40 to 4.940.022
School absence, %, median (IQR)50.0 (65)75.0 (65)25.00.00 to 37.50.069
Allocation to clonidine vs placebo, n (%)
 Clonidine33 (48)25 (56)0.730.34 to 1.560.420
 Placebo36 (52)20 (44)
  • P values are based on χ2 test, Student’s t-test or Mann-Whitney’s test, as appropriate. Due to multiple comparisons, the level of significance is considered equal to 0.05/44=0.00114.

  • BMI, body mass index; CFS, chronic fatigue syndrome; SEID, systemic exertion intolerance disease.