E2 ModerateModerate confidencePEM not requiredCross-SectionalPeer-reviewedReviewed
[Prevalence of chronic fatigue syndrome in 4 family practices in Leiden].
Versluis, R G, de Waal, M W, Opmeer, C et al. · Nederlands tijdschrift voor geneeskunde · 1997
Quick Summary
Researchers in the Netherlands looked at how many people in general medical practices had chronic fatigue syndrome (CFS). They reviewed medical records from about 23,000 patients and found that at least 1-2 out of every 1,000 patients had CFS. Interestingly, they noticed that women were diagnosed with CFS about five times more often than men.
Why It Matters
This study provides early epidemiological data on CFS occurrence in general practice settings, helping establish disease burden in the community. Understanding prevalence is essential for healthcare planning and recognizing that CFS disproportionately affects women, which remains clinically relevant today.
Observed Findings
- At least 1.1 cases of CFS per 1,000 patients in general practice population
- Male-to-female ratio of 1:5 (approximately 83% female)
- 42 patients initially identified as potential CFS cases from 601 preselected patients
- 25 of 42 patients (60%) confirmed by their general practitioners as meeting Holmes' criteria
- General practitioners used 10 different coding systems to label CFS-related conditions
Inferred Conclusions
- CFS is a recognizable condition in primary care settings with a measurable, though possibly underestimated, prevalence
- CFS shows marked female predominance, with women representing approximately 83% of cases
- Diagnostic coding practices in general practice are inconsistent, potentially obscuring true prevalence
- The actual prevalence may be higher than 1.1 per 1,000 due to underdiagnosis in primary care records
Remaining Questions
- What is the true prevalence of CFS when using active case-finding methods rather than passive record review?
- What biological or social factors account for the 5:1 female-to-male ratio in CFS?
What This Study Does Not Prove
This study does not prove what causes CFS or why it affects women more than men. It also cannot establish incidence (new cases) versus prevalence, and the reliance on medical record documentation means some undiagnosed cases in the community were likely missed.
Tags
Symptom:Fatigue
Method Flag:PEM Not DefinedWeak Case DefinitionSmall SampleExploratory OnlyNo Controls
Metadata
- PMID
- 9543740
- Review status
- Editor reviewed
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 12 April 2026
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 →
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