Aim: The 2003 Canadian Consensus Criteria for chronic fatigue syndrome (CFS) are often assumed to suggest low-grade systemic inflammation, but have never been formally validated. This study explored the content validity of the Criteria in a sample of adolescents with CFS selected according to a wide case definition.
Methods: A total of 120 CFS patients with a mean age of 15.4 years (range 12–18 years) included in the NorCAPITAL project were post hoc subgrouped according to the Canadian Consensus Criteria. Those who satisfied the criteria (Criteria positive) and those who did not (Criteria negative) were compared across a wide range of disease markers and markers of prognosis.
Results: A total of 46 patients were classified as Criteria positive, 69 were classified as Criteria negative and five could not be classified. All disease markers were equal across the two groups, except the digit span backward test of cognitive function, which showed poorer performance in the Criteria positive group. Also, the prognosis over a 30 week period was equal between the groups.
Conclusion: This study questions the content validity of the Canadian Consensus Criteria, as few differences were found between adolescent CFS patients who did and did not satisfy the Criteria.
Study findings challenge the content validity of the Canadian Consensus Criteria for adolescent chronic fatigue syndrome, by Tarjei Tørre Asprusten, Even Fagermoen, Dag Sulheim, Eva Skovlund, Øystein Sørensen, Tom Eirik Mollnes and Vegard Bruun Wyller in Acta Paediatrica, 31 January 2015.