Pulmonary arterial hypertension (PAH) is a rare disease that’s not very well known amongst the general population. If you or a loved one is living with PAH, you’ve likely looked into the causes, symptoms, and course of the disease but may still have questions about it.

PAH is a rare lung disease and a form of pulmonary hypertension (PH), which damages the arteries and causes high blood pressure in the lungs. In people with PAH, the right ventricle of the heart needs to work harder to pump blood into the pulmonary arteries. This puts them at risk of right heart failure, blood clots, and other types of heart disease.

Although there is currently no cure for PAH, timely and regular care can help slow disease progression and improve quality of life.

Here are some lesser-known facts about PAH that can help you better understand the condition and get the care you need.

1. PAH Is a Very Rare Disease

PAH is a rare condition that affects approximately 2 to 8 people per million worldwide. Approximately 500 to 1,000 new cases of PAH are diagnosed each year in the United States. About 15 percent to 20 percent of PAH cases are hereditary — known as heritable PAH (hPAH) — and linked to a family history of the disease.

Approximately 30 percent of PAH cases are associated with connective tissue disease, which can damage blood vessels. PAH can also be linked to congenital heart disease.

There are different types of PAH, including:

• Familial PAH— This refers to PAH inherited from a relative with the condition.
• Associated PAH (aPAH) — Some people develop PAH when they have other medical conditions, such as connective tissue disease, congenital heart disease, liver disease, kidney disease, and HIV.
• Idiopathic PAH (iPAH) — This is a type of PAH with an unknown cause.

Treatment approaches vary among the different types of PAH. Treatment for associated PAH involves treating the PAH as well as for the underlying condition. For example, people with aPAH linked to scleroderma (systemic sclerosis) have been found to be less responsive to treatment and at risk for worse outcomes. Scleroderma is a type of connective tissue disease that can affect the vascular system and damage blood vessels.

2. An Accurate Diagnosis of PAH Can Take Several Years

PAH diagnoses are often delayed. According to the American Lung Association, PAH can be difficult to diagnose, and it can take up to two or more years to get a proper diagnosis. A study in Respirology showed that one-third of people with PAH waited more than two years for a diagnosis, and another 25 percent experienced a delay in diagnosis that was almost three years.

One myPHteam member wrote, “While I certainly feel discouraged with my newest diagnosis, I am relieved to have something that confirms all of my heart and lung symptoms.”

“I also struggled to get a diagnosis,” another member said. “So, go to a pulmonologist right away. By the way, you are not crazy — this is a rare and difficult disease to diagnose.”

The consequences of delayed diagnosis are serious. The Respirology study found that people with PAH who waited more than two years for an accurate diagnosis experienced worse outcomes compared to those who were diagnosed sooner. The authors noted that a delay of more than two years was associated with an 11 percent higher risk of death.

Symptoms of PAH, such as shortness of breath, chest pain, or fatigue, can be nonspecific, and many doctors are not trained to recognize signs of PAH, which are key reasons diagnosis is often delayed.

3. Women Have a Higher Risk of Developing PAH Than Men

According to a study in Methodist DeBakey Cardiovascular Journal, females are almost twice as likely to develop PAH as males. According to the study, that ratio lessens among older people: Females over 65 years old are only 20 percent more likely than males to develop PAH. Because younger women have a higher rate of PAH, researchers believe hormones may play a role in the development of PAH.

4. Race and Ethnicity May Play a Role in the Type of PAH a Person Develops

Although more research is needed on this topic, some research studies have found differences in types of PAH across racial and ethnic groups. Understanding racial and ethnic differences in types of PAH can further help doctors in creating specialized PAH treatment plans.

The Pulmonary Hypertension Association reviewed several studies that found PAH types varied across racial and ethnic groups. Among their findings:

• African-Americans with PAH were more likely to have connective tissue disease-associated PAH — that is, PAH associated with scleroderma, rheumatoid arthritis, systemic lupus erythematosus, or mixed connective tissue disease.
• Hispanic people with PAH were more likely to have congenital heart disease-associated PAH.
• Non-Hispanic white people with PAH were more likely to PAH associated with drug or toxin use. They were also more likely to have familial PAH.

5. Socioeconomic Status May Be a Factor in Rates of PAH

Socioeconomic status (SES) — a measure made up of factors like occupation, income, education level, and place of residence — may be a variable in outcomes from PAH. Lower socioeconomic status is linked to inadequate health insurance, delayed diagnosis, and a lack of follow-up care.

One systematic review led authors to recommend that SES be included as a factor in research studies on PAH. The study found that people with PAH and a lower income came to health care centers with more advanced PAH. Diagnosing PAH before it becomes advanced is important for improving treatment outcomes.

Environmental risk factors related to low socioeconomic status, such as high levels of air pollution, exposure to environmental toxins, and lower-quality diet, may also contribute to poorer outcomes from PAH. Researchers have recommended that health care professionals become better educated on the risks associated with lower socioeconomic status in order to ensure health care providers offer appropriate care.

6. PAH Outcomes Have Improved Significantly in Recent Years

In recent decades, better management of PAH has significantly increased survival rates among people living with the disease. The one-year survival rate is now between 86 percent and 90 percent, up from 65 percent in the 1980s, according to the Journal of Investigative Medicine. Average long-term survival during that period increased from 2.8 years to 6 years.

A number of medications can help reduce PAH symptoms. In some advanced cases of PAH, lung transplant may be advised.

Meanwhile, standards for diagnosis and disease management have also improved with tests such as right heart catheterization, echocardiogram and other types of lung and heart imaging, and blood tests, which can evaluate blood flow in the heart and lungs and determine problems with the right side of your heart.

Risk assessment tools help monitor disease progression and provide essential information that can guide treatment plans. People with PAH should be evaluated every three to six months for their risk of mortality. Talk to your doctor to learn more about risk assessment for PAH.

Talk to People Who Understand

On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 48,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.

Are you living with pulmonary arterial hypertension? What have you learned about the disease that has helped you better understand the condition? Share your thoughts and experience in the comments below, or share your story on your Activities page.