Researchers need to increase study sizes and apply strict diagnostic criteria
Polish researchers report that the difficulties with diagnosing ME/CFS and ensuring all research participants have the same condition, can lead to inaccurate research results.
Misdiagnosis can skew results significantly in studies with fewer than 500 participants. If research uses only participants with self-reported ME/CFS and does not check the diagnosis against accepted diagnostic criteria, then the study size needs to increase to improve accuracy.
It is also difficult to determine if results apply to all patients if only a group are studied women, young, old etc. And it is important to check that healthy controls in a study are in fact healthy.
Research studies should therefore have a large number of participants over 500 or 1,000, which could be achieved through multi-centre studies OR care is taken through applying diagnostic criteria and laboratory tests to ensure the group has the same diagnosis.
Research abstract:
Misdiagnosis of myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) can occur when different case definitions are used by clinicians (relative misdiagnosis) or when failing the genuine diagnosis of another disease (misdiagnosis in a strict sense). This problem translates to a recurrent difficulty in reproducing research findings.
To tackle this problem, we simulated data from case-control studies under misdiagnosis in a strict sense. We then estimated the power to detect a genuine association between a potential causal factor and ME/CFS. A minimum power of 80% was obtained for studies with more than 500 individuals per study group. When the simulation study was extended to the situation where the potential causal factor could not be determined perfectly (e.g., seropositive/seronegative in serological association studies), the minimum power of 80% could only be achieved in studies with more than 1000 individuals per group.
In conclusion, current ME/CFS studies have suboptimal power under the assumption of misdiagnosis. This power can be improved by increasing the overall sample size using multi-centric studies, reporting the excluded illnesses and their exclusion criteria, or focusing on a homogeneous cohort of ME/CFS patients with a specific pathological mechanism where the chance of misdiagnosis is reduced.
Impact of Misdiagnosis in Case-Control Studies of Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome, by João Malato Luís Graça, and Nuno Sepúlveda in Diagnostics 13 (3)
[doi:10.3390/diagnostics13030531] 1 Feb 2023
(This article belongs to the Section Pathology and Molecular Diagnostics)
