Lewis, I, Pairman, J, Spickett, G et al. · Journal of internal medicine · 2013 · DOI
Some ME/CFS patients also have POTS (a condition where the heart rate and blood pressure don't adjust properly when standing up). This study found that ME/CFS patients with POTS are younger, experience less severe fatigue and depression, and have different patterns of daytime sleepiness compared to ME/CFS patients without POTS. A simple combination of two questionnaires can accurately identify which ME/CFS patients have POTS, potentially helping doctors decide who needs additional testing and treatment.
POTS is a treatable condition that may coexist in approximately 13% of ME/CFS patients, but distinguishing this subgroup is clinically important because it identifies patients who may benefit from specific autonomic interventions. The identification of a simple two-question screening tool could help clinicians recognize POTS in ME/CFS populations and provide targeted treatment, potentially improving outcomes for this subset of patients.
This study does not establish that POTS causes ME/CFS or vice versa—it only shows they co-occur in some patients with distinct clinical features. The cross-sectional design cannot determine causality, temporal relationships, or whether treating POTS in CFS patients improves overall ME/CFS outcomes. The study also does not explain why CFS+POTS patients report less fatigue despite having orthostatic dysfunction.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Lewis, I, Pairman, J, Spickett, G, & Newton, J L (2013). Clinical characteristics of a novel subgroup of chronic fatigue syndrome patients with postural orthostatic tachycardia syndrome.. Journal of internal medicine. https://doi.org/10.1111/joim.12022
BibTeX
@article{mecfsatlas-lewis-2013-clinical-characteristics,
author = {Lewis, I and Pairman, J and Spickett, G and Newton, J L},
title = {Clinical characteristics of a novel subgroup of chronic fatigue syndrome patients with postural orthostatic tachycardia syndrome.},
journal = {Journal of internal medicine},
year = {2013},
doi = {10.1111/joim.12022},
note = {PubMed: 23206180},
url = {https://www.mecfsatlas.com/evidence/lewis-2013-clinical-characteristics},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/lewis-2013-clinical-characteristics
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