Study results
| Author, year (reference) | Domain | Definition of recovery/partial recovery | Detailed notes on outcome | Proportion recovered |
| Unidimensional outcome | ||||
| Chalder et al, 201023 | School attendance | School attendance ≥70% | Attendance at school/work over a 2-week period as a percentage of expected attendance at 6-month follow-up. Information obtained from parents. Dichotomised outcome set at 70% as many healthy adolescents are not attending full-time school/college at this age |
Family-focused CBT vs psychoeducation: 56% (18/32) vs 29% (9/31) at 3 months 66% (21/32) vs 58% (18/31) at 6 months 59% (19/32) vs 65% (20/31) at 12 months |
| Crawley et al, 20113 | School attendance | Full recovery: full-time attendance | Ascertained at assessment using single-item inventory and through follow-up questionnaires. full time not quantified | 32% (6/19) at 1.5 months 63% (12/19) at 6 months |
| Rowe, 199919 | Self-rated improvement | ‘Participants considered they were well’ | Questionnaire | 60% at mean 56 months (range 15–112 months) |
| Lim and Lubitz, 200224 | Physical activity | ‘Completely back to normal’ assumed to indicate recovery | Self-administered questionnaire with multiple choice answers | 4/41 (10%) immediately following intervention 8/42 (19%) at long-term follow-up (3–5 years) |
| Fatigue | ‘Resolved’ assumed to indicate recovery | 6/41 (15%) following intervention | ||
| Memory and concentration | ‘Better or resolved’ assumed to indicate partial recovery or recovery | 38/42 (90%) during admission | ||
| Social activities | ‘Back to normal or mildly limited in social activities’ assumed to indicate recovery or partial recovery | 22/40 (52%) following intervention 36/41 (88%) at long-term follow-up (3–5 years) | ||
| School attendance | ‘Full time’ assumed to indicate full recovery | 6/39 (15%) following intervention 20/41 (49%) at long term follow-up | ||
| Stulemeijer et al, 200520 | CBT vs waiting list | |||
| Fatigue | Reliable change index >1.96 and fatigue score <35.7 on fatigue subscale of CIS-20* | All measures self-reported | 21/35 (60%) vs 7/34 (21%) at 5 months | |
| Physical functioning | Increase of ≥50 or an end score of ≥75 on physical functioning subscale of SF-36† | 22/35 (63%) vs 8/34 (24%) at 5 months | ||
| School attendance | Full-time school attendance | 19/33 (58%) vs 10/34 (29%) at 5 months | ||
| Self-rated improvement | ‘Completely recovered’ or ‘feel much better’ on 4-point Likert scale | 25/35 (71%) vs 15/34 (44%) at 5 months | ||
| Composite | ||||
| Chalder et al, 200214 | Fatigue school attendance | Improved: attendance at school at ≥75% of the time and a score of <4 on Chalder Fatigue Scale‡ | No explanation of how attendance measured | 83% (15/18) at 6 months |
| Katz et al, 200918 | Clinical evaluation (physical examination, history, blood tests) | Recovered based on complete history, physical examination and laboratory screening | Assessment of recovery status through telephone screening interview | 31% (11/36) at 6 months 52% (17/33) at 18 months |
| Lloyd et al, 2012 (follow-up of Chalder et al, 2010)21 | Fatigue school attendance | Recovery: score ≤18 on the Chalder Fatigue Scale‡ questionnaire and school attendance ≥70% | Score ≤18 chosen in line with cut-off for fatigue recovery defined by25 school attendance assessed by self-reported hours as percentage of expected attendance per week. Cut-off ≥70% used as at this age many healthy adolescents are not attending school or college full time |
Family-focused CBT vs psychoeducation:
79% vs 64% at 24 months |
| Nijhof et al, 201215 | CBT vs usual care | |||
| Fatigue | Fatigue severity score <40 on CIS-20* | Recovery was defined post hoc, in relation to healthy peers±2 SD | 57/67 (85%) vs 17/64 (27%) at 6 months | |
| School attendance | School absence of ≤10% in past 2 weeks | Attendance measured as proportion of classes attended, expressed as a percentage of normal school schedule | 50/67 (75%) vs 10/64 (16%) at 6 months | |
| Physical functioning | Physical functioning score ≥85% on CHQ-CF87 subscale§ | 52/67 (78%) vs 13/64 (20%) at 6 months | ||
| Self-rated improvement | Self-rated as completely recovered or feeling much better¶ | 42/57 (63%) vs 5 (8%) at 6 months | ||
| Composite | 63% (42/67) vs 8% (5/64) at 6 months 64% (41/64) vs 8% (5/63) at 12 months | |||
| Nijhof et al, 2013 (follow-up of Nijhof et al, 2012)22 | Fatigue School attendance Self-rated improvement Physical functioning | Recovery: fatigue severity score <40 on CIS-20†, physical functioning score ≥85% on CHQ-CF87 subscale§, school absence ≤10% in past 2 weeks and self-rated as completely recovered or feeling much better¶ | Recovery was defined post hoc, in relation to healthy peers±2 SD. School attendance measured as the proportion of classes attended, expressed as a percentage of the normal school schedule | 55% (62/112) at 12 months** 59% (66/112) at mean of 2.7 years (range 1.7–3.8 years) |
| Viner et al, 200416 | Global wellness School attendance | Resolution: wellness†† score of ≥90†† and school attendance ≥95% | Average school attendance in previous 3 months measured by families with data verified by telephone contact to school/college or percentage of required weekly contact calculated for those in college |
Programme vs supportive care
43% (11/26) vs 4.5% (1/22) at 6–24 months |
| Van Geelen et al, 201017 | Fatigue | Score <40 on fatigue subscale of CIS-20* | Cut-off score of 40 chosen as it is the mean plus 2 SD of subjective fatigue distribution in healthy adolescents | 30/54 (55.6%) at mean 2.2 years |
| Physical functioning | Score >65 on CHQ-CF87 physical functioning subscale§ | 38/54 (70.4%) at mean 2.2 years | ||
| Composite | 52% (28/54) at mean 2.2 years | |||
*Checklist Individual Strength-20 (CIS-20) consists of 8 items on a 7-point scale with scores ranging from 8 (no fatigue) to 56 (severely fatigued).
†The SF-36 has scores ranging between 0 (maximal physical limitation) and 100 (ability to do vigorous activity), with a subscale for measuring physical functioning.
‡Chalder Fatigue Scale: an 11-item questionnaire measuring physical and mental fatigue on a 4-option Likert continuum to give a total fatigue score. Scoring is bimodal (range from 0 to 11). A score of >4 indicates ‘severe fatigue’.
§CHQ-CF87 is an 87-item questionnaire with a score range of 0%–100%, with 0 indicating maximal physical limitation while 100% indicates the ability to do all activities.
¶Self-rated Improvement was measuring by using a 4-item tool in which patients can indicate whether they have “completely recovered”, “feel much better”, “have the same complaints” or “have become much worse” compared with the measurement before commencement of CFS treatment.
**Paper did not report separate recovery rates for intervention and control arms at long term follow-up.
††Self-rated single item global health wellness score provides a subjective assessment of overall physical and mental well-being and is considered a measure of overall health and quality of life.