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Table 4 Outcome of clonidine intervention – cardiovascular variables

From: Effects of low-dose clonidine on cardiovascular and autonomic variables in adolescents with chronic fatigue: a randomized controlled trial

  Baseline Week 8 (during treatment)
Supine   
Heart rate - beats/min   
 Clonidine group, mean 70 67
 Placebo group, mean 72 69
 Difference (95 % CI)   −2.0 (−4.1 to 0.1)
 p-value (clonidine vs. placebo)   0.06
SBP – mmHg   
 Clonidine group, mean 103 104
 Placebo group, mean 107 103
 Difference (95 % CI)   1.4 (−1.0 to 3.9)
 p-value (clonidine vs. placebo)   0.25
MBP – mmHg   
 Clonidine group, mean 77 78
 Placebo group, mean 80 77
 Difference (95 % CI)   1.3 (−0.7 to 3.4)
 p-value (clonidine vs. placebo)   0.19
DBP – mmHg   
 Clonidine group, mean 65 64
 Placebo group, mean 66 63
 Difference (95 % CI)   0.8 (−1.0 to 2.7)
 p-value (clonidine vs. placebo)   0.37
SI - ml/m2   
 Clonidine group, mean 47 46
 Placebo group, mean 46 46
 Difference (95 % CI)   0.2 (−2.1 to 2.4)
 p-value (clonidine vs. placebo)   0.86
TPRI - mmHg/L/min/m2   
 Clonidine group, mean 9.1 9.4
 Placebo group, mean 8.9 8.9
 Difference (95 % CI)   0.5 (−0.1 to 1.1)
 p-value (clonidine vs. placebo)   0.11
SDNN – ms   
 Clonidine group, mean 74 78
 Placebo group, mean 66 66
 Difference (95 % CI)   12.0 (−0.2 to 23.7)
 p-value (clonidine vs. placebo)   0.05
r-MSSD – ms   
 Clonidine group, mean 79 83
 Placebo group, mean 65 70
 Difference (95 % CI)   13.1 (−3.2 to 29.5)
 p-value (clonidine vs. placebo)   0.11
pNN50 - %   
 Clonidine group, mean 40 40
 Placebo group, mean 31 38
 Difference (95 % CI)   2.2 (−3.0 to 7.3)
 p-value (clonidine vs. placebo)   0.40
LF-HRV – nu   
 Clonidine group, mean 40 42
 Placebo group, mean 43 38
 Difference (95 % CI)   3.7 (−0.5 to 8.0)
 p-value (clonidine vs. placebo)   0.08
HF-HRV – nu   
 Clonidine group, mean 60 58
 Placebo group, mean 57 62
 Difference (95 % CI)   −3.7 (−8.0 to 0.5)
 p-value (clonidine vs. placebo)   0.08
LF-HRV* - ms2   
 Clonidine group, mean 628 679
 Placebo group, mean 451 487
 Ratio (95 % CI)   1.4 (1.1 to 1.8)
 p-value (clonidine vs. placebo)   0.007
HF-HRV* - ms2   
 Clonidine group, mean 962 961
 Placebo group, mean 600 825
 Ratio (95 % CI)   1.2 (0.9 to 1.5)
 p-value (clonidine vs. placebo)   0.28
Total Power-HRV* - ms2   
 Clonidine group, mean 1991 2053
 Placebo group, mean 1352 1638
 Ratio (95 % CI)   1.3 (1.0 to 1.6)
 p-value (clonidine vs. placebo)   0.06
LF/HF-ratio*   
 Clonidine group, mean 0.65 0.70
 Placebo group, mean 0.75 0.59
 Ratio (95 % CI)   1.2 (1.0 to 1.4)
 p-value (clonidine vs. placebo)   0.09
LF-SBP – nu   
 Clonidine group, mean 39.3 38.0
 Placebo group, mean 38.1 36.9
 Difference (95 % CI)   1.1 (−3.0 to 5.2)
 p-value (clonidine vs. placebo)   0.60
LF-SBP* - mmHgs2   
 Clonidine group, mean 3.8 3.7
 Placebo group, mean 3.0 3.2
 Ratio (95 % CI)   1.1 (0.9 to 1.5)
 p-value (clonidine vs. placebo)   0.34
Response to 20° head-up tilt   
Heart rate - beats/min   
 Clonidine group, mean 5.2 4.9
 Placebo group, mean 4.8 4.9
 Difference (95 % CI)   0.0 (−1.1 to 1.2)
 p-value (clonidine vs. placebo)   0.97
SBP – mmHg   
 Clonidine group, mean 0.74 −0.59
 Placebo group, mean 0.15 −0.01
 Difference (95 % CI)   −0.58 (−2.2 to 1.0)
 p-value (clonidine vs. placebo)   0.48
MBP - mmHg   
 Clonidine group, mean 1.19 0.61
 Placebo group, mean 0.94 1.23
 Difference (95 % CI)   −0.63 (−2.1 to 0.8)
 p-value (clonidine vs. placebo)   0.39
DBP - mmHg   
 Clonidine group, mean 1.13 1.2
 Placebo group, mean 1.58 1.8
 Difference (95 % CI)   −0.59 (−2.0 to 0.8)
 p-value (clonidine vs. placebo)   0.40
SI - ml/m2   
 Clonidine group, mean −5.9 −4.5
 Placebo group, mean −5.1 −5.3
 Difference (95 % CI)   0.9 (−0.4 to 2.1)
 p-value (clonidine vs. placebo)   0.17
TPRI - mmHg/L/min/m2   
 Clonidine group, mean 0.66 0.44
 Placebo group, mean 0.60 0.62
 Difference (95 % CI)   −0.18 (−0.47 to 0.11)
 p-value (clonidine vs. placebo)   0.22
SDNN - ms   
 Clonidine group, mean −5.1 −7.9
 Placebo group, mean −4.4 −0.7
 Difference (95 % CI)   −7.2 (−16.0 to 1.6)
 p-value (clonidine vs. placebo)   0.11
r-MSSD - ms   
 Clonidine group, mean −18 −24
 Placebo group, mean −16 −17
 Difference (95 % CI)   −7.6 (−19.6 to 4.4)
 p-value (clonidine vs. placebo)   0.11
pNN50 - %   
 Clonidine group, mean −14 −11
 Placebo group, mean −9 −13
 Difference (95 % CI)   1.2 (−3.1 to 5.4)
 p-value (clonidine vs. placebo)   0.59
LF-HRV - nu   
 Clonidine group, mean 8.3 6.1
 Placebo group, mean 6.7 9.2
 Difference (95 % CI)   −3.1 (−7.4 to 1.1)
 p-value (clonidine vs. placebo)   0.15
HF-HRV - nu   
 Clonidine group, mean −8.3 −6.1
 Placebo group, mean −6.7 −9.2
 Difference (95 % CI)   3.1 (−1.1 to 7.4)
 p-value (clonidine vs. placebo)   0.15
LF-HRV# - ms2   
 Clonidine group, mean −320 −161
 Placebo group, mean −176 −171
 n.a.   n.a.
 p-value (clonidine vs. placebo)   0.87
HF-HRV# - ms2   
 Clonidine group, mean −828 −640
 Placebo group, mean −523 −629
 n.a.   n.a.
 p-value (clonidine vs. placebo)   0.99
Total Power-HRV# - ms2   
 Clonidine group, mean −1107 −790
 Placebo group, mean −668 −736
 n.a.   n.a.
 p-value (clonidine vs. placebo)   0.78
LF/HF-ratio   
 Clonidine group, mean 0.35 0.34
 Placebo group, mean 0.44 0.55
 Difference (95 % CI)   −0.21 (−0.46 to 0.04)
 p-value (clonidine vs. placebo)   0.09
LF-SBP - nu   
 Clonidine group, mean 2.5 4.4
 Placebo group, mean 3.2 3.7
 Difference (95 % CI)   0.7 (−2.4 to 3.8)
 p-value (clonidine vs. placebo)   0.66
LF-SBP - mmHgs2   
 Clonidine group, mean −2.6 −1.0
 Placebo group, mean −0.6 −0.2
 Difference (95 % CI)   −0.7 (−1.7 to 0.3)
 p-value (clonidine vs. placebo)   0.17
  1. Missing values were imputed based on the principle of last observation carried forwards. Thus, all calculations are based on 120 individuals (60 in each intervention group). Means and differences at week 8 are estimated from the parameters of the general linear model
  2. For variables annotated with a *, modeling was performed on ln-transformed variables; all means are based on back-transformation of the variables, and ratios instead of differences are reported. For variables annotated with a #, modeling was performed on square root-transformed variables; all means are based on back-transformation of the variables, but neither differences nor ratios can be computed, as indicated with the label n.a. (not applicable). CI = Confidence Interval; SBP = Systolic Blood Pressure; MBP = Mean arterial Blood Pressure; DBP = Diastolic Blood Pressure; SI = Stroke Index; TPRI = Total Periferal Resistance Index; RRI = R-R Interval; HRV = heart rate variability; HF = High Frequency; LF = Low Frequency; SDNN = standard deviation of all RR-intervals; pNN50 = the proportion of successive RRIs with adifference greater than 50 ms; r-MSSD = the square root of the mean square differences of successive RRIs; nu = normalized units; n.a. = not applicable because of square root transformation of variables; n = number of patients, for most variables equal to 60 because of imputation