Functional Class and Risk Assessment: Two Important Pieces of the PAH Puzzle

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by United Therapeutics |

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Those living with pulmonary arterial hypertension (PAH) know that managing symptoms is important in everyday life. You’re likely familiar with Functional Class, a standard system that classifies how severe your PAH symptoms are when doing daily activities.

There are four classes:

  • Class 1: You are not overly fatigued or breathless when doing daily activities, and these symptoms do not limit your physical activities.
  • Class 2: You feel fatigued, breathless, chest pain, or almost fainting when doing daily activities, resulting in slight limits on your physical activities.
  • Class 3: You feel fatigued, breathlessness, chest pain, or almost fainting, resulting in pronounced limits on your physical activities.
  • Class 4: You are generally unable to do daily activities without symptoms and feel fatigued and breathless even at rest, resulting in significant limits on your physical activities.

Your Role in Determining Your Functional Class

Your Functional Class is based on the information you provide when your healthcare provider asks you questions about your symptoms and activities. It’s important to be open and honest with your answers.

Consider sharing specific activities that trigger symptoms for you, what these symptoms are, and how frequently these symptoms occur. It can also be helpful to share what activities do not trigger symptoms for you or if you’re avoiding activities and not making plans with friends and family because of your symptoms.

Being open and honest allows your healthcare team to accurately determine your Functional Class, which is an essential part of an overall risk assessment and helping them recommend ways that can better manage your symptoms.

How We Use Functional Class Has Changed Over Time

Our understanding of PAH and Functional Class has come a long way in recent years. We better understand how PAH progresses and how Functional Class doesn’t fully reflect that state of your unique PAH but is still an important piece of the overall picture.

In the past, your healthcare provider used your Functional Class to determine your treatment plan after your diagnosis, monitor how your PAH progressed over time, and adjust your treatment plan if your symptoms worsened.

Today, Functional Class is used differently. Since your symptoms worsen after changes occur in your heart, many PAH experts and specialists do not consider using Functional Class alone as the best way to monitor your disease or determine when to make changes to your treatment plan. PAH experts and specialists are more proactive in treating PAH to prevent symptoms before they happen.

Changes in your heart graph

Functional Class Is Just One Part of an Overall ‘Risk Assessment’  

PAH experts now understand Functional Class is just part of the story of your unique PAH based on research that was validated in thousands of patients.  Like you, those patients were all unique, but some clear patterns emerged. Those patterns identified the most meaningful tests and how often the tests should be performed. It’s called Risk Assessment.

Risk Assessment allows your healthcare provider to get a fuller picture of your PAH by combining your Functional Class and other individual test results into a “risk status.”

Your risk status helps determine if you’re getting the most out of your current treatment plan or if changes need to be made. So while Functional Class is an essential piece of the PAH puzzle, on its own, it may not help you and your healthcare team see the whole picture.

Why Your Risk Status Matters: Now and in the Future

Your risk status can be low risk, intermediate risk, or high risk—the lower your risk status, the better the outlook (“prognosis”) for your PAH. Your risk status can change with successful treatment and lifestyle changes. That’s why getting to low-risk status (or staying there) is now a goal for many patients and their healthcare providers.

Low-risk status means that most of your test results are in the low-risk category and that you have a higher chance of living longer (i.e., an increased chance of survival in the coming years). Better test results also mean you are likely able to do more daily activities with fewer symptoms.

Risk Assessment is now an established practice among PAH specialists and a best practice included in PAH treatment guidelines. Guidelines recommend doing a risk assessment every 3 to 6 months to see if your current treatment plan is working. If your risk status isn’t improving fast enough, your healthcare provider may be able to recommend changes to improve your risk status.

Talking with your healthcare team about your risk status could be the key to doing more today and improving your chance of living longer.

At your next visit, ask your healthcare provider about your Functional Class and risk status. Be sure to talk thoroughly and truthfully with them about your symptoms and other factors of your condition. Doing so can help your healthcare team accurately assess your PAH and find ways to help improve how you feel, allowing you to do more every day.


You can learn more about Functional Class and risk status at

Consider joining the PAH Initiative for more knowledge and inspiration to help you stay informed, stay motivated, and stay focused on your future.

This article was sponsored by the PAH Initiative, where knowledge meets inspiration. The PAH Initiative, sponsored by United Therapeutics, is dedicated to advancing patient care in pulmonary arterial hypertension.


Highland KB, Crawford R, Classi P, et al. Development of the Pulmonary Hypertension Functional Classification Self-Report: A patient version adapted from the World Health Organization Functional Classification measure. Health Qual Life Outcomes. 2021;19(1):202. doi:10.1186/s12955-021-01782-0

Hung CC, Cheng CC, Huang WC, et al. Management of pulmonary arterial hypertension patients with World Health Organization Functional Class II. Acta Cardiol Sin. 2020;36(6):583-587. doi:10.6515/ACS.202011_36(6).20200507A

Besinque GM, Lickert CA, Pruett JA. The myth of the stable pulmonary arterial hypertension patient. Am J Manag Care. 2019;25(3 Suppl):S47-S52.

Galiè N, Channick RN, Frantz RP, et al. Risk stratification and medical therapy of pulmonary arterial hypertension. Eur Respir J. 2019;53(1):1801889. doi:10.1183/13993003.01889-2018

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