Clinical research studyOrthostatic instability in a population-based study of chronic fatigue syndrome
Section snippets
Materials and methods
This study adhered to human experimentation guidelines of the US Department of Health and Human Services and complied with the Helsinki Declaration. All participants were volunteers who gave informed consent.
Stand-up screening test
To screen for autonomic nervous system dysfunction, all 113 study subjects underwent a stand-up test during the arrival medical evaluation.29 The stand-up test recorded systolic and diastolic blood pressure and heart rate after 30 minutes in a recumbent position, immediately upon standing, and after standing for 5 minutes. Standing was performed without support or swaying. Orthostatic instability is suggested by a heart rate increase >30 beats per minute above supine baseline (either
Results
There were no significant differences in age, sex, or race/ethnicity between subjects who agreed to participate in the study (Table 2) and those who did not.
Participation
Significantly more subjects with chronic fatigue syndrome were ineligible for head-up tilt table testing than were nonfatigued controls (P = .05). Performance of the tilt test was limited by refusal (7 chronic fatigue syndrome and 1 control), use of antidepressants (15 chronic fatigue syndrome and 4 controls), use of anti-hypertensives (10 chronic fatigue syndrome and 9 controls), exclusionary medical conditions (3 chronic fatigue syndrome, 2 controls), melancholic depression (1 chronic fatigue
Discussion
In this study we found no association between chronic fatigue syndrome and orthostatic instability/intolerance as measured by stand-up or head-up tilt table testing. Participants were screened to insure exclusion of those with possible confounding factors such as underlying medical/psychiatric diseases, older age, and medication use. The study design was particularly powerful because subjects with chronic fatigue syndrome represented those with the illness in the general population rather than
References (41)
- et al.
Idiopathic orthostatic intolerance and postural tachycardia syndromes
Am J Med Sci
(1999) - et al.
Does the chronic fatigue syndrome involve the autonomic nervous system?
Am J Med
(1997) - et al.
Hemodynamic instability score in chronic fatigue syndrome and in non-chronic fatigue syndrome
Semin Arthritis Rheum
(2002) - et al.
Orthostatic intolerance in the chronic fatigue syndrome
J Auton Nerv Syst
(1999) - et al.
Autonomic testing in patients with chronic fatigue syndrome
Am J Med
(1998) - et al.
Autonomic function and serum erythropoietin levels in chronic fatigue syndrome
J Psychosom Res
(2004) - et al.
The Multidimensional Fatigue Inventory (MFI)psychometric qualities of an instrument to assess fatigue
J Psychosom Res
(1995) - et al.
Neurocardiogenic syncopediagnosis, mechanisms, and treatment
Cardiol Clin
(1993) - et al.
The roles of orthostatic hypotension, orthostatic tachycardia, and subnormal erythrocyte volume in the pathogenesis of the chronic fatigue syndrome
Am J Med Sci
(2000) - et al.
Hypovolemia in syncope and orthostatic intolerancerole of the renin-angiotensin system
Am J Med
(1997)