Have you or a loved one been diagnosed with paroxysmal nocturnal hemoglobinuria (PNH)? If the answer is yes, you’re likely wondering how PNH may affect you or your loved one’s life span. Here we’ll break down how various factors affect prognosis (outlook), the most common causes of death in PNH, and how treatment has greatly improved the outlook for PNH in the past few decades.

Survival Rates for PNH

PNH is a rare blood condition in which a person’s immune system attacks their red blood cells. This condition can look different for everyone. In some people, hemolysis (breakdown of the cells) causes symptoms that can be severe or even life-threatening. Other people with PNH have mild symptoms that require minimal treatment and that never progress to life-threatening complications (conditions that occur after PNH has developed). A few people may never experience any symptoms from PNH.

Historical studies from the 1990s, cited in the journal Clinical Advances in Hematology & Oncology, found that people lived for an average of 10 to 15 years after a PNH diagnosis. More recently, a long-term study of people with PNH found that the average survival was 22 years. This improvement is likely due to improved treatment options, including complement inhibitors (medications that block part of the immune system), blood transfusion (receiving donated blood), and bone marrow transplant (transfer of the soft tissue inside most bones from a donor).

Impact of Eculizumab

Eculizumab (Soliris) is a type of medication called a monoclonal antibody. Monoclonal antibodies are proteins designed to attach to a specific target (cell or protein) to treat disease. Eculizumab targets the complement system, which is a group of proteins that usually helps protect the body from infection, but in PNH, the complement system also damages red blood cells.

According to a study published in the journal Blood, individuals with PNH who take eculizumab are much less likely to experience blood clots. Since complement inhibitors have become available, people with PNH are now living longer. Some doctors believe that the life span of those with PNH is now close to that of the general population. Ultomiris, a formulation of ravulizumab, is another complement inhibitor approved by the U.S. Food and Drug Administration (FDA) for treating PNH.

Factors Affecting PNH Prognosis

Various factors affect prognosis in any condition, and PNH is no different. Factors like age, genetic variation, race/ethnicity, sex, and comorbid conditions (occurring at the same time) may affect the outlook of a person with any condition. Here we’ll discuss factors that affect the prognosis for people with PNH.

Age

PNH develops most often in adulthood. Based on current research, the outlook for PNH can be worse in people who develop the condition after the age of 40. The risk of developing thrombosis (blood clots) is also higher in people with PNH who are over age 55. The negative effect of older age is probably because of delays in starting treatment.

Race/Ethnicity

The risk of developing PNH is not influenced by a person’s race or ethnicity. However, there’s an increased incidence (occurrence rate) of blood clots in people with PNH (and worse prognosis) in the United States and Europe than in Asian countries. The reason for this finding isn’t well understood, but it may have to do with differences in reporting between countries.

Pancytopenia

Pancytopenia — low levels of white blood cells, red blood cells, and platelets — is a complication that happens in many conditions. Historically, pancytopenia has been related to worse survival in PNH. This is especially true in those who experience high levels of hemolysis as part of their condition. New treatments that specifically target the immune system have greatly improved the prognosis for individuals diagnosed with PNH and pancytopenia.

Most Common Causes of Death in PNH

A study from The New England Journal of Medicine found that at least 50 percent of deaths in people with PNH are directly caused by PNH or bone marrow failure. In bone marrow failure, your body doesn’t produce all of the blood cells and platelets you need. Here we’ll review the most common causes of morbidity (low quality of life) and mortality (death) in people with PNH.

Blood Clots

Blood clots are the most common cause of death among people living with PNH. Blood clots are collections of blood cells that usually form to prevent too much bleeding when an injury happens. Blood clots become a problem when they occur in the wrong places or at the wrong time. PNH causes blood clots because of chronic (ongoing) hemolysis.

The Aplastic Anemia and MDS International Foundation cites that at least 1 out of 3 people with PNH will develop a blood clot. These blood clots most often occur within the veins of the legs, arms, or lungs, but they can also occur in other parts of the body. Importantly, people who have blood clots when they develop PNH are five times more likely to die within four years of diagnosis.

Myelodysplastic Syndromes and Acute Myeloid Leukemia

Myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) are two complications of PNH that can decrease a person’s life span. MDS are a group of conditions that cause low levels of blood cells from bone marrow failure. MDS develops in about 2 percent to 8 percent of people with PNH. The outlook for people with PNH who develop MDS varies based on their genetics. Certain gene differences can lead to a worse or better prognosis.

Sometimes, MDS can progress to AML. AML is a rare complication of PNH and has a very poor prognosis. Acute myeloid leukemia gets its name from the type of cell that becomes cancerous — the myeloid cell. Immature myeloid cells live in the bone marrow and can eventually turn into white blood cells (WBCs), red blood cells, or platelets. AML that develops after MDS is difficult to treat.

Infection

People living with PNH can experience complications caused by a weak immune system. People diagnosed with PNH often have lower levels of white blood cells in their body. WBCs are responsible for many immune system functions. As a result, people with PNH can be at risk of developing various life-threatening infections.

Two large studies that looked at the cause of death in people with PNH found that infection was one of the main complications. In one study, 40 percent of participants died from infection. In the other, an infection caused death in about 32 percent of participants.

Kidney Disease

Kidney disease in PNH is caused by a buildup of hemoglobin (the protein that carries oxygen and is released by the breakdown of red blood cells) in the kidney system and by low nitric oxide levels. Nitric oxide helps keep blood vessels open. When levels are low, the kidneys and other organs can be injured by low blood flow.

Kidney disease is a rare complication of PNH. People with PNH who develop kidney disease have a greater risk of death. A study published in the Journal of Korean Medical Science found that 8 percent to 18 percent of deaths in participants with PNH were caused by kidney failure.

Live Longer With PNH

Living with a chronic condition can be overwhelming. The good news is that there are now many ways to live longer with PNH. With the right management strategies and a strong support system, individuals with PNH can lead fulfilling lives while managing their condition.

Get Vaccinated

PNH and its treatments can increase the risk of life-threatening infections. If you have PNH, getting vaccinated against bacterial and viral infections is an important part of staying well while living with PNH. Talk to your hematologist (a doctor who specializes in conditions that affect blood) about the risks and benefits of vaccines to find out which are right for you.

Keep Track of Symptoms

Monitoring your symptoms is also important. Tracking symptoms such as abdominal pain, fatigue, and chest pain and keeping your health care team aware of changes will help them recommend the most appropriate treatment for you.

Be Careful With Air Travel

If you have PNH, you’ll need to take extra precautions while flying. The lower oxygen levels when flying can cause chest pain in people with hemolytic anemia (low red blood cell counts from cell breakdown). Before flying, make sure to get your blood counts checked. If you have anemia, get it treated before flying.

Air travel also increases the risk of blood clots. If it’s safe to do so, get up and walk around every couple of hours while in flight and drink plenty of water.

Find the Right Treatment

If you need treatment based on symptoms of your PNH, staying on effective medication is essential to improving your quality of life and living longer. Finding the right treatment can take time. A good starting point is to work closely with your doctor to discuss treatment options and seek support from others who are successfully managing PNH.

Talk With Others Who Understand

On myPNHteam, the social network for people with paroxysmal nocturnal hemoglobinuria and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with PNH.

Are you living with PNH? Share your experience in the comments below, or start a conversation by posting on your Activities page.