Comorbidity of postural orthostatic tachycardia syndrome and chronic fatigue syndrome in an Australian cohort

Abstract

Abstract. Reynolds GK, Lewis DP, Richardson AM, Lidbury BA (The John Curtin School of Medical Research, The Australian National University, Canberra; Donvale Medical Centre, Donvale, Victoria; and Faculty of Education, Science, Technology and Mathematics, The University of Canberra, Canberra, Australia). Comorbidity of postural orthostatic tachycardia syndromeand chronic fatigue syndrome in an Australian cohort. J Intern Med 2014; 275: 409-417.Objective. Patients with chronic fatigue syndrome (CFS) are frequently diagnosed with comorbid postural orthostatic tachycardia syndrome (POTS), suggesting a shared pathogenesis. The aim of this study was to examine the relationship between demographic characteristics, autonomic functioning and fatigue levels amongst CFS patients with and without comorbid POTS.Design and setting. All patients presenting to the CFS Discovery Clinic between 2009 and 2012 completed a 20-min standing task as part of their initial assessment. Heart rate and pulse pressure were recorded at baseline, at 2-min intervals poststanding, at the end of the task and following a recovery period. Average heart rate and pulse pressure variability were calculated from this data. Age, gender, length of illness and self-reported fatigue scores were also recorded. POTS patients were diagnosed by an orthostatic increase in heart rate >30 beats per min, concomitant symptoms of orthostatic intolerance and no orthostatic hypotension. Differences in autonomic functioning between POTS and CFS patients were compared using independent samples t-tests, whilst logistic and linear regressions were performed to examine the contribution of autonomic functioning to task completion and perceived fatigue, respectively. Results. Comorbidity of CFS and POTS (CFS-POTS)was observed in 11% (33/306) of patients. CFS-POTS patients were significantly younger (P < 0.001), had a shorter length of illness (P = 0.034), experienced greater task difficulty (P = 0.002) and were able to stand for significantly shorter periods compared to the CFS-only patients (P < 0.001). CFS-POTS patients experienced significantly lower baseline diastolic blood pressure (P = 0.002), significantly higher heart rate and lower pulse pressures at each standing measurement. Early heart rate changes (P = 0.002) and overall heart rate change (P < 0.001) were significant predictors of completion status, whereas heart rate variability (P < 0.001) and female gender (P < 0.001) were significant predictors of increased perceived task difficulty.Conclusions. Haemodynamic and demographic differences between CFS-POTS and CFS-only patients suggest that the former group reflects a distinct subgroup of the CFS population. The findings highlight the utility of screening younger patients with fatigue for POTS, and identified heart rate variability as an important marker of fatigue for CFS patients in general.

Weighting of orthostatic intolerance time measurements with standing difficulty score stratifies ME/CFS symptom severity and analyte detection

“…The CFS Discovery orthostatic intolerance (standing test) protocol is described in detail elsewhere [10]. Briefly, participants were required to stand, unaided for a maximum of 20 min after a period of repose necessary for baseline (pre-standing) measurements.…”

“…The standing test is used by clinicians to assess the degree of orthostatic intolerance (OI) in a variety of conditions, including ME/CFS, and for the assessment of cardiovascular response [10, 11], as well as to study of orthostatic hypotension and tachycardia [12]. In addition to time measurements, the standing test can include a subjective score of standing difficulty, which reflects an array of symptoms, for example pre-syncope and pain.…”

A prospective 1-year study of postural tachycardia and the relationship to non-postural versus orthostatic symptoms

“…chronic fatigue syndrome (CFS), fibromyalgia) such as fatigue, dizziness, and lightheadedness, may be over-diagnosed with POTS. There has been much work on the coexistence of CFS and POTS, and it appears that younger age groups are more likely to co-express both disorders [6,16,21]. There has been interesting work looking at patients with common underlying pathophysiological mechanisms where POTS and CFS coexist.…”

Chronic Fatigue Syndrome: Case Definitions, Possible Causes, and Therapies

“…23 Such concurrence was observed in 11% (33/306) of patients seen at a clinic between 2009 and 2012, particularly in younger patients with a shorter duration of illness. POTS was diagnosed by noting an orthostatic increase in HR > 30 beats per minute in a 20-minute standing task.…”