Table 2.

Diagnostic criteria used in included studies to define ME/CFS (if reported)

Study	Diagnostic criteria used
Antcliff et al. [25]	No diagnostic criteria included Participants had diagnosis of chronic low back pain, chronic widespread pain, fibromyalgia and ME/CFS for ≥ 3 months’
Antcliff et al. [63]	No diagnostic criteria included Participants had diagnosis of chronic low back pain, chronic widespread pain, fibromyalgia and ME/CFS for ≥ 3 months’
Antcliff et al. [50]	No diagnostic criteria included Participants had diagnosis of chronic low back pain, chronic widespread pain, fibromyalgia and ME/CFS for ≥ 3 months’
ME association. [55]	No diagnostic criteria included Survey open to anyone who had had ME, CFS, or post-viral fatigue syndrome
Bourke et al. [61]	Oxford criteria (PACE trial sub-analysis)
Brown et al. [54]	Fukuda criteria
Brown et al. [60]	No diagnostic criteria included
Dougall et al. [59]	Oxford criteria (PACE trial sub-analysis)
Geraghty et al. [67]	No diagnostic criteria included Survey open to anyone who had ME/CFS. According to self-report, 72% received a diagnosis of by a specialist, 22% from a general practitioner (family doctor), and 4.5% from other professional
Jason et al. [53]	Fukuda criteria
Kos et al. [48]	Fukuda criteria
Meeus et al. [49]	Fukuda criteria
Nijs et al., 2009 [64]	Fukuda criteria
O’Connor et al. [58]	Fukuda criteria
Sharpe et al. [56]	Oxford criteria (PACE trial sub-analysis)
White et al. [35]	Oxford criteria (PACE trial)
White et al. [57]	Oxford criteria (PACE trial sub-analysis)