The prospects of the Two-Day Cardiopulmonary Exercise Test (CPET) in ME/CFS patients: a meta-analysis, by Eun-Jin Lim, Eun-Bum Kang, Eun-Su Jang and Chang-Gue Son in JCM Vol 9 Issue 12 Dec 2020 [10.3390/jcm9124040] (This article belongs to the Special Issue Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: Diagnosis and Treatment)
The diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is problematic due to the lack of established objective measurements. Post-exertional malaise (PEM) is a hallmark of ME/CFS, and the two-day cardiopulmonary exercise test (CPET) has been tested as a tool to assess functional impairment in ME/CFS patients. This study aimed to estimate the potential of the CPET.
We reviewed studies of the two-day CPET and meta-analyzed the differences between ME/CFS patients and controls regarding four parameters: volume of oxygen consumption and level of workload at peak (VO2peak, Workloadpeak) and at ventilatory threshold (VO2@VT, Workload@VT).
The overall mean values of all parameters were lower on the 2nd day of the CPET than the 1st in ME/CFS patients, while it increased in the controls. From the meta-analysis, the difference between patients and controls was highly significant at Workload@VT (overall mean: −10.8 at Test 1 vs. −33.0 at Test 2, p < 0.05), which may reflect present the functional impairment associated with PEM.
Our results show the potential of the two-day CPET to serve as an objective assessment of PEM in ME/CFS patients. Further clinical trials are required to validate this tool compared to other fatigue-inducing disorders, including depression, using well-designed large-scale studies.