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Table 1 Definitions of improvement and recovery specified in the trial protocol [1], and those used in the final trial reports [2, 4]. Improvement was the primary outcome measure specified in the protocol. Recovery was a secondary measure

From: Rethinking the treatment of chronic fatigue syndrome—a reanalysis and evaluation of findings from a recent major trial of graded exercise and CBT

  Definition A: Specified in trial protocol Definition B: Used in published reports
Overall Improvement Minimum score of 75 on the 100-point SF-36 physical function scale or a score increase of 50% or more. At least an 8 point increase in the 100-point SF-36 physical function scale.
Of the 11 fatigue items on the Chalder Fatigue Questionnaire (CFQ), three or fewer rated as worse/much worse than prior to illness OR the total items rated worse/much worse dropped by at least a 50%. At least a 2 point decrease on the 33-point CFQ (Likert scoring method).
Recovery Minimum score of 85 on the 100-point SF-36 physical function scale. Minimum score of 60 on the 100-point SF-36 physical function scale.
Of the 11 items on the CFQ, three or fewer rated as worse/much worse than prior to illness. Maximum score of 18 on the 33-point CFQ.
Overall health self-rated as “very much better” on the Clinical Global Impression scale [50]. Overall health self-rated as “much better” or “very much better” on the Clinical Global Impression scale.
The final “caseness” criterion was met if the patient no longer fulfilled: The Oxford case definition of CFS; the CDC criteria [51]; AND the London ME criteria [52]. (As determined by a non-blinded assessor). The revised “caseness” criterion was met if ANY of the following applied: a) the patient did not meet the standard Oxford case definition; OR b) on the CFQ, they rated less than six of the 11 fatigue items as being worse than prior to illness; OR c) their SF-36 Physical Function score was greater than 65.
  1. CFQ Chalder Fatigue Questionnaire