To examine blood pressure circadian rhythm in subjects with chronic fatigue syndrome (CFS) and appropriate normal and fatigued controls to correlate parameters of blood pressure regulation with perception of fatigue in an observational cohort study. The cause of CFS remains unknown and there are no effective treatments.
To address whether inactivity was a confounder, we performed a 24-hour ambulatory blood pressure monitoring in the following three subject groups: 1) CFS patients (Fukuda Diagnostic criteria) (n = 38); 2) normal controls (n = 120); and 3) a fatigue comparison group (n = 47) with the autoimmune liver disease primary biliary cirrhosis (PBC). All patients completed a measure of fatigue severity (Fatigue Impact Scale). In view of the different demographics between the patient groups, patients were age- and sex-matched on a case-by-case basis to normal controls and blood pressure parameters were compared.
Compared with the control population, the CFS group had significantly lower systolic blood pressure (p < .0001) and mean arterial blood pressure (p = .0002) and exaggerated diurnal variation (p = .009). There was a significant inverse relationship between increasing fatigue and diurnal variation of blood pressure in both the CFS and PBC groups (p < .05).
Lower blood pressure and abnormal diurnal blood pressure regulation occur in patients with CFS. We would suggest the need for a randomized, placebo-controlled trial of agents to increase blood pressure such as midodrine in CFS patients with an autonomic phenotype.
CFS = chronic fatigue syndrome; SBP = systolic blood pressure; MAP = mean arterial pressure; HR = heart rate; DBP = diastolic blood pressure; PBC = primary biliary cirrhosis; FIS = Fatigue Impact Scale.
From the Institute for Cellular Medicine, University of Newcastle, Newcastle-upon-Tyne, United Kingdom.
Address correspondence and reprint requests to Julia L. Newton, Cardiovascular Investigation Unit, Institute of Cellular Medicine, Newcastle University, Newcastle, UK, NE2 4HH. E-mail: firstname.lastname@example.org
Received for publication June 16, 2008; revision received October 15, 2008.
Supported by ME Research UK (J.N.), Medical Research Council (J.N. and D.J.).
Acknowledgments and declarations: None of the authors have any conflict of interest.