Table 1.

Description of included studies and data sets. RCT = randomised control trial; UCT = uncontrolled trial

Intervention trials
Refs	Type of pacing and duration of intervention (if relevant)	Study design (RCT, observational cohort, etc.)	Trial registered or not	Participants (n, age, gender, ethnicity, time since diagnosis)	Comorbidities	Location	Recruitment setting snd study setting	Adherence	Outcome measures	Results (improvement or not, baseline to post-pacing intervention)	PEDro Score
Antcliff et al. [50]	Six-week rehabilitation programme using the activity pacing framework (6 × 3.5 h sessions) Programme included understanding of e.g. graded exercise, relaxation and goal setting etc. Pacing was instructed in one session but not informed or standardised by any particular guide or framework	Single-arm, repeated measures study, a non-randomised feasibility study	Registered at ClinicalTrials.gov: NCT03497585	n = 107 Predominantly female (86%). Mean age 55.25 ± 12.83	Lower back pain (73.8%), CFS/ME (11.2%), 61.3% of participants reported two or more conditions of chronic pain and/or fatigue. 11.2% participants with CFS/ME, 83% reported ME/CFS as main condition, and 92% at least one comorbidity of LBP (64%), chronic widespread pain (55%), fibromyalgia (64%) or another condition (27%)	Northern England, UK	One National Health Service (NHS) pain service	The median number of rehabilitation programme sessions attended of total 6 sessions was five (58.9% participants attended ≥ 5 sessions); 83.2% participants attended at least one activity pacing session and 56.1% attended both activity pacing sessions 100% of participants attended at least one activity pacing specific session and 54 (83.1%) participants attended both activity pacing sessions	APQ-28 CFQ EQ-5D-5L GAD-7 NRS PASS-20 PHQ-9 PSEQ SF-12	Pacing improved mean scores of all symptoms	5
Kos et al. [48]	Coached activity pacing self- management. Three individual therapy sessions of 60–90 min/wk for three consecutive weeks of either “activity pacing self-management” or “Relaxation therapy”	RCT with ‘relaxation’ as control	Registered at ClinicalTrials.gov (NCT01512342	n = 33 (n = 16 in the experimental group, n = 17 in the control group) 41 ± 11 years All female Ethnicity and time since diagnosis not reported	Not reported	Belgium	Waiting list for multidisciplinary rehabilitation and informed about the study through email University Hospital	25% drop-out in the experimental group, 18% in the control group	CFS Symptom list CIS COPM SF-36	Pacing improved COPM performance (33% of group) Pacing improved satisfaction (42% of group) Pacing improved CIS	6
Meeus et al. [49]	One pacing and self-management education one-to-one session for 30 min	RCT with one pain physiology education one-to-one session as control for 30 min	Registered at University Hospital Brussels	n = 48 38 ± 11 years Male = 8 (16.7%) Ethnicity and time since diagnosis not reported	Not reported	Belgium	Medical files available at university-based chronic fatigue clinic	5% dropouts	NPQ PCI PCS (Dutch) PPT TSK	Pain physiology education session group improved knowledge of neurophysiology of pain compared to pacing group Pain physiology education session group improved Pain catastrophizing scale compared to pacing group	9
Nijs et al. [51]	Pacing self-management. Five different visits at 1-week intervals. Wore accelerometer for 24 h for a week	Case series	Not a registered trial	n = 7 43 ± 13 years All female Median illness duration of 96 ± 44 months	Not reported	Belgium	University-based chronic fatigue centre University Hospital	22% dropouts	CFS CFS-APQ CFS Symptom list CIS COPM SF-36 VAS	Pacing improved CFS Pacing improved COPM Pacing improved VAS Pacing did not improve SF-36 Pacing did not improve CFS Pacing did not improve CIS	6
White et al. [35]	One year (52 weeks)of activity pacing therapy (APT)	RCT with graded exercise therapy (GET) and cognitive behavioural therapy (CBT), or specialised medical care (SMC) as comparators	Registered (PACE http://isrctn.org, number ISRCTN54285094.)	n = 641 (recruited), n = 630 (analysed), n = 607 (reported) 39 ± 12 years 76% women 94% white Duration of illness 32 (16–66) months	Co-morbid psychiatric condition (47%) Depressive disorder (33%)	UK	outpatients attending six specialist chronic fatigue syndrome clinics	8% dropouts	CFQ CGI HADS JSS London criteria for ME SF-36 WSAS	Pacing did not improve fatigue, but CBT and GET did Pacing did not improve physical function, but CBT and GET did Pacing did not improve physical function, but CBT and GET did	6
Observational studies
Antcliff et al. [25]	No intervention, but assessment of perceptions of pacing. Phone interview after received postal study and APQ-38 questionnaire	Cross-sectional observational	Not a registered trial	n = 16 Adult patients, and were aged ≥ 18 years Duration of illness (all ≥ 3 months’ duration) No mention of sex or ethnicity of patients	Chronic low back pain, chronic widespread pain, fibromyalgia	North West England, UK	Physiotherapy out-patients department in NHS Trust Physiotherapy out-patients	Not reported	APQ-38 CPCI PARQ	Most participants who implemented pacing reported it was beneficial	3
Antcliff et al. [63]	No intervention, but assessment of perceptions of pacing	Cross-sectional observational	Not a registered trial	n = 257 Adult patients Age, sex, and ethnicity are not reported	Chronic low back pain, chronic widespread pain, fibromyalgia and CFS/ME	UK	Physiotherapy out-patients department in NHS Trust Postal questionnaires and physiotherapy at hospital	83% enrolled were included in final analyses	APQ-38 APQ-26 CFQ HADS NRS PASS-20 SF-12	Activity adjustment was associated with higher levels of current pain, depression and avoidance, and lower levels of physical function Activity consistency was associated with lower levels of physical fatigue, depression and avoidance and higher levels of physical function Activity progression was associated with higher levels of current pain Activity planning was significantly associated with lower levels of physical fatigue, and activity acceptance was associated with higher levels of current pain and avoidance	4
BacME Association [55]	No intervention, but assessment of perceptions of pacing	Cross-sectional observational	Not a registered trial	n = 1428 (CBT = 493; GET = 233; pacing = 226) 78% female Time since diagnosis: 1–2 years 2%; 3–4 years 6%; 3–4 years 13%; 5–6 years 12%; 7–10 years 20%; 11–21 years 29%; 21–30 years 13%; > 30 years 5% Age and ethnicity not reported	Not reported	UK	Online platform (ME Association website) launched May 2012 Open to anyone with ME, CFS or post-viral fatigue syndrome	N/A	Appropriateness of treatment experience Common ME symptoms severity (several) Disability benefits Employment and education Illness severity PEM	Pacing was reported to be the most effective, safe, acceptable and preferred form of activity management	3
Brown et al. [60]	No intervention, but assessment of energy envelope	Cross-sectional observational	Not a registered trial	n = 91 83% female 87% white	Not reported	Chicago metropolitan area, USA	Newspaper and physician referrals, and support groups 46% were referred by physicians, 34% through media advertisements, and 20% from “other sources” Setting unclear	20% drop out	bCOPE EEQ PEM from CFSMQ SF-36	Cluster 1 (individuals highly outside the energy envelop) experienced high levels of PEM severity and impaired physical function Cluster 2 (those better staying within their energy envelope) experienced higher levels of physical functioning, and lower PEM severity Cluster 3 (symptomatic and mildly overextended) was comprised of individuals who were the least outside of their energy envelope, but were impaired on physical function, and had high levels of PEM	3
Brown et al. [54]	One year of 13, 45 min sessions of CBT with GET, anaerobic activity, cognitive coping skills, and relaxation bi-weekly Treatments were collapsed in this paper Analysis concerned participants within and outside their energy envelope	Prospective observational	Not a registered trial	n = 44 82% female 91% white At least 18 years of age	Not reported	Chicago, USA	Physician referrals, media advertisements, and ME/CFS support groups Setting unclear	61% drop out	Actigraph CFS EEQ FSS SF-36	Pacing improved physical function and fatigue compared to those outside their energy envelope	3
Geraghty et al. [52]	No intervention, but assessment of perceptions of pacing and other treatments. Online survey open for 4 months	Cross-sectional observational compared to BacME Association (2015) survey	Not a registered trial	n = 1428 compared to n = 16,665 Average illness duration 4.4 years Most respondents were female (79%)	Not reported	UK	Online platform advertised nationally and open for 4 months	N/A	Appropriateness of treatment experience Common ME symptoms severity (several) Disability benefits Employment and education Illness severity PEM (same as BacME Association [2015] survey)	Pacing improved symptoms (44% of respondents), or worsened symptoms (14% of respondents)	2
Jason et al. [53]	No intervention, but assessment of energy envelope	Prospective observational	Not a registered trial	n = 110 At least 18 years old Physically capable of attending scheduled sessions Sex and ethnicity not reported	Not reported	Chicago, USA	Newspaper and physician referrals, and support groups 46% were referred by physicians, 34% through media advertisements, and 20% from “other sources” Setting unclear	3.5% drop out	BAI BDI-II BPI CFS DSM-IV FSS GSE PSS PSQI SF-36 QOLS	Pacing was associated with less PEM incidence, less depression, less anxiety, less fatigue, better sleep, better quality of life, better physical functioning and vitality, less difficulties with work or daily activities Pacing was associated with less frequency of exercise avoidance, and less fatigue impairing daily activities	3
O’Connor et al. [58]	No intervention, but assessment of energy envelope	Cross-sectional observational	Registered s (institutional review board approval #LREC 1 – 08/H0906/5)	n = 181 83% female 98% Caucasian Age and Time since diagnosis not reported	Not reported	UK and Norway	Hospital setting	Not reported	DSQ EEQ SF-36	Pacing was associated with better physical function scores, total symptom scores, and engaged in more hours of activity	4
Sub-analysis of pace
Bourke et al. [61]	PACE Trial re-analysis so APT Duration of 52 weeks	RCT with GET, CBT, and SMC as comparators	Registered (PACE http://isrctn.org, number ISRCTN54285094.)	n = 641 Around 90% at least caucasian Mean age 39 years Mostly female 76%	Depressive disorder 34%	UK	Patients from secondary-care specialist CFS clinic	Drop out 5%	ACR CDC criteria Oxford criteria for CFS	CBT and GET improved pain more than APT and SMC	7
Dougall et al. [59]	PACE Trial re-analysis so APT Follow-up interviews were conducted 12, 24, and 52 weeks after randomisation	RCT with GET, CBT, and SMC as comparators	Registered (PACE http://isrctn.org, number ISRCTN54285094.)	n = 641 Sex, age and ethnicity not reported	Not reported	UK	Patients from six secondary care clinics with a diagnosis of CFS	Not reported	AES CBRQ CDC criteria CFS DSM-IV PHQ-15 HADS JSS London criteria for ME Oxford criteria for CFS SF-36 SEMCD	Pacing worsened physical function (25% of group) more than SMC (18%), GET (11%) and CBT (9%) No other between-group differences	4
Sharpe et al. [56]	PACE Trial re-analysis so APT 12, 24, and 52 week, and long-term follow-up measures	2 year follow-up of RCT with GET, CBT, and SMC as comparators	Registered (PACE http://isrctn.org, number ISRCTN54285094.)	n = 481 (75%) participants from the PACE trial 39 ± 12 years 76% female 94% white Duration of illness 32 (16–66) months	Psychiatric disorder (46%) Depressive disorder (32%)	UK	PACE trial database	75% of participants from the PACE Trial responded Adherence N/A	CFQ PCGI SF-36 WSAS	Pacing improved fatigue and physical function similar to CBT and GET at follow-up	7
White et al. [57]	PACE Trial re-analysis so APT. 52 weeks follow-up after randomisation	RCT with GET, CBT, and SMC as comparators	Registered (PACE http://isrctn.org, number ISRCTN54285094.)	n = 640 39 ± 12 years 76% female 94% white Duration of illness 32 (16–66) months	Co-morbid psychiatric condition (47%) Depressive disorder (33%)	UK	PACE trial database	0.2% drop-out	CDC criteria CFQ CGI London ME criteria Oxford criteria for CFS SF-36	Pacing participants were less likely to recover (8%) than the CBT group (22%), or GET group (22%) Pacing participants were as recover (as the SMC group (7%)	6

APT = Adaptive Pacing Therapy. BMI = Body mass index. CBRQ = Cognitive Behavioural Responses Questionnaire. CBRQ-SF = Cognitive Behavioural Responses Questionnaire symptom focussing sub-scale. CBT = Cognitive Behaviour Therapy. CFQ = Chandler fatigue questionnaire. CIS = Checklist individual strength questionnaire for fatigue. DSQ = DePaul Symptom Questionnaire. EDAq: Avoidance resting score on Symptom Interpretation questionnaire. FSS = Fatigue severity scale. GAD = Generalised anxiety disorder. GET = Graded Exercise Therapy. HADS A = Hospital Anxiety and Depression Scale anxiety score. JSS = Jenkins sleep scale. 6MWT = Six metres walked in six minutes. PASS-20 = Escape and avoidance subscale of the Pain Anxiety Symptoms Scale-20. SF-36 = 36-Item Short Form Health Survey questionnaire. UK = United Kingdom. USA = United States of America. WSAS = Work and Social Adjustment Scale