Prevalence of Idiopathic Erythrocytosis in the World Population
The largest study estimates the frequency of idiopathic erythrocytosis at approximately 1.1 per 1,000 subjects (0.11% or 110 per 100,000), which is notably higher than the prevalence of polycythemia vera. 1
Global Epidemiologic Data
Published Prevalence Estimates
The most robust prevalence figure comes from a large cohort study reporting 1.1 per 1,000 subjects for idiopathic erythrocytosis, representing the best available population-level estimate 1
This prevalence is higher than that observed in polycythemia vera, suggesting idiopathic erythrocytosis may be more common than previously recognized 1
Critical Limitations in Global Data
The true worldwide prevalence remains largely unknown due to significant diagnostic and epidemiologic gaps, particularly in low- and middle-income countries 2
Systematic population-based research on idiopathic erythrocytosis is virtually absent in most regions, creating substantial uncertainty about true global burden 2
In countries like India, limited access to specialized molecular testing (JAK2 V617F, exon 12 mutations) means many cases are likely undiagnosed or misclassified as other conditions 2
The diagnosis requires exclusion of polycythemia vera, secondary causes, and familial forms—a work-up that demands comprehensive laboratory capabilities not universally available 2
Diagnostic Context Affecting Prevalence Estimates
JAK2 Mutation Testing Impact
Among idiopathic erythrocytosis patients with low serum erythropoietin levels, JAK2 exon 12 mutations are detected in 27%, reclassifying these cases as a variant of myeloproliferative neoplasm rather than true idiopathic disease 3
In a cohort of 181 individuals initially diagnosed with idiopathic erythrocytosis, only 58 (32%) had low to normal erythropoietin levels warranting JAK2 exon 12 mutation screening 3
This suggests that published prevalence figures likely overestimate true idiopathic erythrocytosis, as more sophisticated molecular testing reclassifies many cases 1, 3
Clinical Characteristics of Study Populations
Large cohort studies have examined 78 patients with idiopathic erythrocytosis compared to 21 with familial erythrocytosis and 136 with polycythemia vera 4
Idiopathic erythrocytosis patients characteristically have lower white blood cell counts, lower platelet counts, higher serum erythropoietin levels, and less frequent splenomegaly compared to polycythemia vera patients 4
No simple clinical features reliably distinguish idiopathic from familial erythrocytosis, necessitating genetic testing in young patients with sporadic erythrocytosis 4
Geographic and Population Variations
No population-specific prevalence data exist for most regions worldwide, representing a critical knowledge gap 2
Urgent population-based epidemiological studies are needed to establish true prevalence across different ethnic groups and geographic regions 2
The heterogeneous mechanisms underlying idiopathic erythrocytosis—including unrecognized secondary causes, congenital polycythemias, and genetic mutations in oxygen-sensing pathway proteins—suggest prevalence may vary substantially by population 1, 5
Clinical Implications of Prevalence Data
Idiopathic erythrocytosis is a stable disease with low thrombotic risk and minimal tendency toward progression to acute leukemia or myelofibrosis 1
The transition from idiopathic erythrocytosis to polycythemia vera is rare when sophisticated diagnostic techniques are employed, supporting the validity of the diagnostic category 1
Clinicians should maintain high suspicion for idiopathic erythrocytosis, as diagnosed cases likely represent only a fraction of true prevalence due to diagnostic limitations 2