Rethinking the treatment of chronic fatigue syndrome-a reanalysis and evaluation of findings from a recent major trial of graded exercise and CBT.

BACKGROUND: The PACE trial was a well-powered randomised trial designed to examine the efficacy of graded exercise therapy (GET) and cognitive behavioural therapy (CBT) for chronic fatigue syndrome. Reports concluded that both treatments were moderately effective, each leading to recovery in over a fifth of patients. However, the reported analyses did not consistently follow the procedures set out in the published protocol, and it is unclear whether the conclusions are fully justified by the evidence. METHODS: Here, we present results based on the original protocol-specified procedures. Data from a recent Freedom of Information request enabled us to closely approximate these procedures. We also evaluate the conclusions from the trial as a whole. RESULTS: On the original protocol-specified primary outcome measure - overall improvement rates - there was a significant effect of treatment group. However, the groups receiving CBT or GET did not significantly outperform the Control group after correcting for the number of comparisons specified in the trial protocol. Also, rates of recovery were consistently low and not significantly different across treatment groups. Finally, on secondary measures, significant effects were almost entirely confined to self-report measures. These effects did not endure beyond two years. CONCLUSIONS: These findings raise serious concerns about the robustness of the claims made about the efficacy of CBT and GET. The modest treatment effects obtained on self-report measures in the PACE trial do not exceed what could be reasonably accounted for by participant reporting biases.

Assessment of recovery status in chronic fatigue syndrome using normative data.

INTRODUCTION: Adamowicz et al. have reviewed criteria previously employed to define recovery in chronic fatigue syndrome (CFS). They suggested such criteria have generally lacked stringency and consistency between studies and recommended future research should require "normalization of symptoms and functioning". METHODS: Options regarding how "normalization of symptoms and functioning" might be operationalized for CFS cohorts are explored. RESULTS: A diagnosis of CFS excludes many chronic disabling illnesses present in the general population, and CFS cohorts can almost exclusively consist of people of working age; therefore, it is suggested that thresholds for recovery should not be based on population samples which include a significant proportion of sick, disabled or elderly individuals. It is highlighted how a widely used measure in CFS research, the SF-36 physical function subscale, is not normally distributed. This is discussed in relation to how recovery was defined for a large intervention trial, the PACE trial, using a method that assumes a normal distribution. Summary data on population samples are also given, and alternative methods to assess recovery are proposed. CONCLUSIONS: The "normalization of symptoms and function" holds promise as a means of defining recovery from CFS at the current time. However, care is required regarding how such requirements are operationalized, otherwise recovery rates may be overstated, and perpetuate the confusion and controversy noted by Adamowicz et al.