Polycythemia Vera Facts and Statistics: What You Need to Know

Polycythemia vera is a blood cell disorder that causes the body to make too many blood cells. The incidence of new cases is approximately 1 to 3 out of 100,000 people in the United States. This condition is considered rare. It requires lifelong treatment, which can improve quality of life, overall health, and survival.

This article will discuss facts and statistics related to polycythemia vera, including how common it is, the populations affected, causes, risk factors, early detection, and mortality rates.

Polycythemia Vera Overview 

Polycythemia vera is a chronic disease that can have mild to moderate effects for some people, but it can also have severe effects. The disease causes an increase in red blood cells, and sometimes it also causes excess white blood cells and platelets. 

Mild forms of this condition do not always cause symptoms. When they occur, symptoms can include weight loss, dizziness, tinnitus (ringing in the ears), enlarged spleen, abdominal pain, enlarged liver, headaches, gum bleeding, nosebleeds, bruising, chest pain, and itching.

Complications of polycythemia vera can be life-threatening and include hypertension (high blood pressure), breathing problems, blood clots, myelofibrosis (bone marrow scarring), and leukemia (a type of white blood cell cancer).

How Common Is Polycythemia Vera? 

The prevalence of polycythemia vera is approximately 1 in 3,300 people in the United States. This includes newly diagnosed people and those who have had it for any length of time.

Polycythemia Vera by Ethnicity

A family history of the polycythemia vera is a known risk factor for this condition, although it usually occurs without any family history.

Some studies suggest that polycythemia vera is more common among Black Americans than White Americans. And it has also been found to be more common among people of Ashkenazi Jewish ancestry (an ancestral group in Central and Eastern Europe).

Polycythemia Vera by Age and Gender 

Polycythemia vera is a disease that develops and begins to show signs and symptoms during adulthood. The most common age for signs and symptoms of polycythemia vera to appear is in the 50s, but it can occur at any age.

Males are more likely to develop polycythemia vera than females.

Causes of Polycythemia Vera and Risk Factors

People who have polycythemia vera have an overproduction of red blood cells in the bone marrow. This can occur due to several Janus kinase 2 (JAK2) gene mutations. This gene is involved in regulating the production of blood cells. The mutation is not usually inherited—it can occur spontaneously.

Some health conditions can increase the risk of polycythemia vera. These include autoimmune diseases (in which a person's immune system mistakenly attacks their own tissues), bone marrow cancer, and treatment for bone marrow cancer.

Additionally, certain lifestyle factors and environmental exposures are associated with an increased risk of polycythemia vera.

Exposure to chemicals associated with certain professions can raise risks, including in:

• Jobs or other activities with petroleum or benzene exposure
• Poultry workers
• Photographers
• Agricultural workers

Certain toxins may trigger damage in a person’s DNA, causing the mutation that leads to polycythemia vera. These toxins may be inhaled or may come into contact with the skin, such as during work.

What Are the Mortality Rates for Polycythemia Vera? 

Management of polycythemia vera includes treatments to reduce the number of red blood cells in the body, such as phlebotomy (removal of cells through an intravenous line) and medication to lower the production of blood cells. Additionally, some people may need treatment for blood clots, bleeding, or other complications.

While the median survival time for polycythemia vera after diagnosis is approximately 15 years, the survival time is extended to 35 years if the person was diagnosed before the age of 40.

The prognosis and treatment plan may also depend on age, including:

• Low risk: Younger than 60 and no history of blood clots
• High risk: Over 60 or a history of blood clots

In an international study of 1,545 people with polycythemia vera, leukocytosis (high white blood cells), blood clots in one or more veins, and an identified mutation were associated with a lower survival among all age groups. 

Screening and Early Detection 

People who are at risk of polycythemia vera may need periodic screening with a complete blood count (CBC), which can detect changes in red blood cell count, hemoglobin, hematocrit, red blood cell size and shape, white blood cell count, or platelets.

According to the World Health Organization (WHO), criteria for the diagnosis of polycythemia vera require either all three major criteria, or the first two major criteria plus the minor criterion.

Major Criteria

Criterion 1:

• Hemoglobin: Higher than 16.5 grams per deciliter (g/dL) in men, or higher than 16.0 g/dL for women
• Hematocrit: Higher than 49% in men or higher than 48% in women
• Red cell mass: Higher than 25% above normal value

Criterion 2:

• Increased blood cells with an increased difference in blood cell size and shape. Blood cell trilineage, which means that the precursor cells can produce red blood cells, white blood cells, or platelets.

Criterion 3:

• The presence of JAK2 V617F mutation or JAK2 exon 12 mutation

Minor Criterion

Erythropoietin level in the serum is expected to be below normal. Erythropoietin is a hormone that the body makes. It stimulates the bone marrow to make new red blood cells.

When red blood cells are too high, erythropoietin levels typically decrease so the body won't make too many red blood cells. With polycythemia vera, the body makes too many red blood cells even with low erythropoietin. This is because of the genetic changes that trigger red blood cell production.

Summary

Polycythemia vera is a rare disease that causes excessive red blood cells to be produced and circulate in the body. The condition occurs during adulthood.

The effects and prognosis can vary, and certain factors are associated with a worse prognosis—older age, a high white blood cell count, blood clots, and a genetic abnormality. Treatment can improve the outcome. Treatments vary based on the blood cell counts, symptoms, and complications.