Clinically accessible tools for documenting the impact of orthostatic intolerance on symptoms and function in ME/CFS.
Lee, Jihyun, Wall, Pelle, Kimler, Chris et al. · Work (Reading, Mass.) · 2020 · DOI
Quick Summary
This study looked at how much time ME/CFS patients can spend upright (standing or walking around) each day and how this relates to dizziness and other symptoms caused by orthostatic intolerance—a condition where symptoms get worse when standing or being active. Researchers compared 25 women with ME/CFS to 25 healthy women and found that ME/CFS patients spend far fewer hours upright and experience much worse symptoms that interfere with daily life. The study suggests that measuring upright hours and asking patients about orthostatic symptoms could be helpful tools for doctors diagnosing and managing ME/CFS.
Why It Matters
Many ME/CFS patients struggle with orthostatic symptoms that worsen with activity, but clinicians lack simple, standardized tools to assess this problem. This study validates that measuring upright hours and using questionnaires about orthostatic symptoms could help doctors better diagnose ME/CFS and track how treatment affects patients' ability to function. These accessible clinical tools may improve recognition and management of a key feature of ME/CFS that significantly impacts patients' lives.
Observed Findings
ME/CFS patients reported significantly fewer hours of upright activity per day compared to healthy controls.
Patients with <5 hours upright activity experienced more severe orthostatic symptoms than those with ≥5 hours.
Only 33% of ME/CFS study participants were employed, and all employed patients achieved ≥5 upright hours with an average of 8 hours daily.
ME/CFS patients reported greater interference with daily activities due to orthostatic symptoms than healthy controls.
Orthostatic intolerance symptom severity appeared to correlate with upright activity capacity in ME/CFS patients.
Inferred Conclusions
Hours of upright activity and standardized orthostatic intolerance assessments may serve as clinically useful tools for ME/CFS diagnosis and management.
Orthostatic intolerance is more prevalent and severe in ME/CFS patients than in healthy individuals and significantly impacts daily functioning and employment.
OI symptom severity may be dose-dependent on activity level, though the functional impact remains substantial across activity levels.
The marked reduction in upright tolerance in ME/CFS may be a key barrier to employment and rehabilitation.
Remaining Questions
Does orthostatic intolerance cause reduced upright tolerance in ME/CFS, or does reduced activity capacity trigger orthostatic deconditioning—or both?
What This Study Does Not Prove
This study shows correlation between reduced upright hours and orthostatic symptoms but does not prove that orthostatic intolerance directly causes reduced activity capacity—the relationship could be bidirectional or influenced by other factors. The small sample size (25 per group) and inclusion of only women limits generalizability to all ME/CFS patients. The study design cannot establish whether orthostatic intolerance is the primary driver of disability or one of multiple contributing factors in ME/CFS.
Tags
Symptom:Orthostatic IntoleranceFatigue
Method Flag:PEM Not DefinedWeak Case DefinitionSmall Sample
How do these findings apply to male ME/CFS patients and those from different racial/ethnic backgrounds?
Would targeted interventions to manage orthostatic intolerance improve patients' ability to increase upright activity and employment status?
How do other ME/CFS symptoms (post-exertional malaise, cognitive dysfunction, pain) interact with orthostatic intolerance to determine overall functional capacity?