Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study. — CFSMEATLAS
Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study.
Eccles, Jessica A, Thompson, Beth, Themelis, Kristy et al. · Clinical medicine (London, England) · 2021 · DOI
Quick Summary
This study looked at whether joint hypermobility (unusual flexibility and loose joints) is connected to fibromyalgia and ME/CFS. Researchers found that most patients with these conditions also had signs of hypermobility, and that higher hypermobility scores matched with worse symptoms. The results suggest that hypermobility is often missed in diagnosis, even though it significantly affects how sick people feel.
Why It Matters
This research highlights that connective tissue disorders are frequently overlooked in ME/CFS patients despite having significant clinical impact. Recognizing hypermobility as a common co-occurring condition could improve diagnosis accuracy and guide targeted treatments, potentially improving quality of life for many ME/CFS patients who remain undiagnosed.
Observed Findings
Eighty-one percent of fibromyalgia and ME/CFS patients met Brighton criteria for hypermobility syndrome versus lower rates in healthy controls
Eighteen percent of patients met 2017 hypermobile Ehlers-Danlos syndrome (hEDS) criteria
Hypermobility scores significantly predicted symptom severity levels in patient groups
Exceptional overlap was observed between fibromyalgia and ME/CFS presentations
Higher odds ratio (7.08) for hypermobility in patient group compared to controls
Inferred Conclusions
Symptomatic hypermobility is highly prevalent in fibromyalgia and ME/CFS and appears clinically relevant to symptom burden
Hypermobility is substantially underdiagnosed in these patient populations despite its quality-of-life impact
Fibromyalgia and ME/CFS may share hypermobility as a common pathophysiological mechanism or risk factor
Diagnostic protocols for fibromyalgia and ME/CFS should routinely include assessment for connective tissue hypermobility
Remaining Questions
Does hypermobility represent a primary mechanism driving ME/CFS symptoms or a secondary consequence of chronic illness?
What This Study Does Not Prove
This study does not prove that hypermobility causes ME/CFS or fibromyalgia—it only shows they occur together. The observational design means we cannot determine the direction of causality or whether hypermobility is a primary driver of symptoms versus a coincidental feature. The study's small size and lack of age/sex-matched controls also limit how broadly these findings apply to the full ME/CFS population.