E2 ModerateModerate confidencePEM ?Cross-SectionalPeer-reviewedMachine draft
Subtyping Patients with Myalgic Encephalomyelitis (ME) and Chronic Fatigue Syndrome (CFS) By Course of Illness.
Stoothoff, Jamie, Gleason, Kristen, McManimen, Stephanie et al. · Journal of biosensors, biomarkers and diagnostics · 2017 · DOI
Quick Summary
This study looked at how ME/CFS progresses differently in different people. Researchers asked 541 patients to describe how their illness changed over time—whether it stayed the same, got worse, got better, or went up and down. They found that patients with different illness patterns had different symptom severity and ability to function, suggesting that grouping patients by how their illness progresses could help doctors better understand and treat the condition.
Why It Matters
ME/CFS presents with highly variable disease courses and outcomes, making it difficult to identify homogeneous patient populations for research and treatment. This study provides evidence that classifying patients by illness trajectory may be clinically meaningful and could improve clinical trial design, prognostic accuracy, and personalized treatment approaches. Better patient stratification could accelerate research progress and help clinicians provide more targeted care.
Observed Findings
- 59.7% of patients reported a Fluctuating illness course, while 15.9% reported Constantly Getting Worse and 8.5% reported Relapsing and Remitting patterns
- Illness trajectory groups showed statistically significant differences in symptom severity on select domains of the DSQ
- Functional disability (measured by SF-36 subscales) varied significantly across different illness course groups
- Overall energy expenditure levels differed significantly between trajectory groups
- Only 1.9% of patients reported a Constantly Getting Better trajectory
Inferred Conclusions
- Illness trajectory-based subtyping may create more homogeneous patient groups than previous classification systems
- Different illness courses are associated with distinct patterns of symptom severity and functional impairment
- Trajectory classification shows promise as a clinically meaningful way to stratify ME/CFS patients for research and treatment purposes
Remaining Questions
- Do these trajectory patterns remain stable over time, or do patients shift between categories? Which biological or clinical factors predict which trajectory a patient will follow? Does knowing a patient's trajectory help predict treatment response or long-term prognosis? How do the five trajectory categories compare to other patient classification systems, and which is most clinically useful?
What This Study Does Not Prove
This study does not establish what causes different illness trajectories or whether illness course predicts long-term prognosis—it captures a snapshot at one point in time. The self-reported illness classification was not verified against objective clinical data, and the cross-sectional design cannot determine whether trajectory classification causes different symptoms or is simply associated with them. Results do not prove that trajectory-based subtyping is superior to other classification methods.
Tags
Symptom:Post-Exertional MalaiseCognitive DysfunctionPainFatigue
Method Flag:PEM Not DefinedWeak Case DefinitionExploratory Only