By F.N.M. Twisk and L.A.M.M. Corsius
Myalgic Encephalomyelitis (ME) and Chronic Fatigue Syndrome (CFS) are considered to be enigmatic diseases. Several studies propose that the combination of cognitive behaviour therapy with a graded activity protocol (CBT+), justified by a so-called (bio)psychosocial (explanatory) model, is an effective treatment option for CFS (ME).
Objective :A critical review of five Dutch hallmark studies that allegedly support this claim.
Methods: An analysis of the five CBT+ studies with special attention to the patients studied, the criteria (subjective and objective measures and cut-off scores) used to select participants and to define improvement and recovery, the consistency of the definitions of caseness (being diagnosed as a CFS patient at entry) versus the definitions of improvement and recovery after CBT+, and the objective effects.
Results: The studies investigated suffer from various methodological flaws. Apart from these methodological shortcomings, the claim that CBT+ is an effective treatment option for CFS is not substantiated by the data reported. Some studies investigated CFS patients, other studies investigated CF patients, labelled as CFS patients, or combinations of CFS and CF patients. No study investigated the effect of CBT+ in a group of patients meeting the (original) diagnostic criteria for ME. The effects of CBT+ on subjective measures, for example fatigue and disability, if present, are insufficient to achieve normal values. Impressive recovery and improvement rates are based on very loose criteria for subjective measures. Cut-off scores for subjective measures used to define improvement and recovery in studies show overlap with cut-off scores for CFS caseness in one or more of the other studies. More importantly, looking at the objective measures, the proof of clinical improvement after CBT+ is lacking.
Conclusion: Solid evidence of effectiveness of CBT+ for CFS, let alone ME, is lacking in the five hallmark studies. The lack of objective improvement indicates CBT+ is ineffective. This finding confirms the outcome of the large-scale PACE-trial in the UK.
: Twisk FNM (2017) An analysis of Dutch hallmark studies confirms the outcome of the PACE trial: cognitive behaviour therapy with a graded activity protocol is not effective for chronic fatigue syndrome and Myalgic Encephalomyelitis. Gen Med Open
, 2017 doi: 10.15761/GMO.1000117 (Full article)