Pulmonary Arterial Hypertension (PAH)


Prevalence of PAH

Pulmonary arterial hypertension (PAH) is a rare condition with an estimated prevalence of 15 to 50 cases per million within the US and Europe. It is difficult to determine the exact overall prevalence of pulmonary arterial hypertension due to its heterogeneous signs and symptoms and underdiagnosis. Around 52.6% of PAH cases are idiopathic, heritable, or anorexigen-induced. Although PAH occurs more commonly in females aged 30 to 60 years, it can occur in males, who in most cases have worse clinical outcomes.1

A National Institutes of Health (NIH) registry that included PAH data from 1981 to 1985 found it was 1.7 times more frequent in females, the mean age of presentation was 36 years±15, and patients survived a mean 2.8 years from diagnosis.1

An observational 2006 US-based registry called REVEAL (Registry to Evaluate Early and Long-Term PAH Disease Management) found a mean age of 53 among PAH patients, female predominance (79.5% females), and a female-to-male ratio of 4.8:1. Further, 46% of cases were idiopathic PAH, 25% of cases were associated with connective tissue diseases, and 10% were associated with congenital heart diseases. The mean duration between symptom onset and diagnosis was found to be 2.8 years. Long-term survival analysis found survival rates of 85% at year 3, 68% at year 5, and 49% at year 7, from the time of diagnosis.2

Presently, the mean age of patients diagnosed with PAH is about 50 years to 65 years, in contrast to the mean age of 36 years determined by the NIH registry. In addition, the current median survival is 7 years, compared to 2.8 years determined by the NIH registry. The NIH registry determined the 1-, 3-, and 5-year survival rates to be 68%, 48%, and 34%, respectively. With the advent of multiple PAH therapies, recent registries show improved survival of 89-96% at 1 year and 73-77% at 3 years.3

A recent systematic review, which included epidemiologic studies (national registries, clinical databases, or administrative databases) from 2003-2020, found that the incidence of PAH in adults ranged from 1.5 to 32 cases per million and the prevalence of PAH in adults ranged between 12.4 to 268 cases per million, with a range of 20-fold for both PAH incidence and prevalence. An analysis of the recent national systematic registry data (within the last 5 years) from centralized health care systems showed the PAH incidence in adults is approximately 5.8 cases per million, while the range of PAH prevalence in adults is 47.6-54.7 cases per million.4

Epidemiology of PAH Types

Idiopathic PAH has a prevalence of 6-10 cases per million in Western countries.5 The most common type of PAH is secondary to connective tissue diseases, with systemic sclerosis (SSc) being most commonly associated with PAH (around 8%-12% of SSc patients) followed by systemic lupus erythematosus (1%-5% of patients develop PAH) and mixed connective tissue disease (3%-4% of patients develop PAH).6

The prevalence of PAH in patients with human immunodeficiency virus (HIV) infection is estimated to be around 0.5%, which is about 2000 times greater than in the general population.7,8 It is difficult to accurately determine the prevalence of PAH associated with portal hypertension. However, epidemiologic studies have estimated the prevalence to range between 5% to 15% in PAH patients.9 The prevalence of PAH associated with congenital heart disease (CHD) in adults is estimated to range between 4.2% and 28%.10 The exact prevalence of PAH associated with schistosomiasis is not known, however, studies have estimated the prevalence to be around 5% to 10% cases with hepatosplenic schistosomiasis, which makes it one of the leading causes of PAH worldwide.11 The incidence of persistent pulmonary hypertension of the newborn syndrome is around 2 cases per 1000 live births, with a mortality rate of 4% to 33%.12

References

  1. Levine DJ. Pulmonary arterial hypertension: updates in epidemiology and evaluation of patients. Am J Manag Care. 2021;27(3):S35-S41. doi:10.37765/ajmc.2021.88609
  2. McGoon MD, Benza RL, Escribano-Subias P, et al. Pulmonary arterial hypertension: epidemiology and registries. J American College of Cardiology. 2013;62:D51-D59. doi:10.1016/j.jacc.2013.10.023
  3. Swinnen K, Quarck R, Godinas L, Belge C, Delcroix M. Learning from registries in pulmonary arterial hypertension: Pitfalls and recommendations. Eur Respir Rev. 2019;28(154). doi:10.1183/16000617.0050-2019
  4. Leber L, Beaudet A, Muller A. Epidemiology of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: identification of the most accurate estimates from a systematic literature review. Pulm Circ. 2021;11(1):2045894020977300. doi:10.1177/2045894020977300
  5. Knafl D, Gerges C, King CH, Humbert M, Bustinduy AL. Schistosomiasis-associated pulmonary arterial hypertension: a systematic review. Eur Respir Rev. 2020;29(155). doi:10.1183/16000617.0089-2019
  6. Zanatta E, Polito P, Famoso G, et al. Pulmonary arterial hypertension in connective tissue disorders: Pathophysiology and treatment. Exp Biol Med. 2019;244(2):120-131. doi:10.1177/1535370218824101
  7. Simenauer A, Nozik-Grayck E, Cota-Gomez A. The DNA damage response and HIV-associated pulmonary arterial hypertension. Int J Mol Sci. 2020;21(9). doi:10.3390/ijms21093305
  8. Barnett CF, Hsue PY. Human immunodeficiency virus-associated pulmonary arterial hypertension. Clin Chest Med. 2013;34(2):283-292. doi:10.1016/j.ccm.2013.01.009
  9. Thomas C, Glinskii V, de Jesus Perez V, Sahay S. Portopulmonary hypertension: from bench to bedside. Front Med. 2020;7:569413. doi:10.3389/fmed.2020.569413
  10. Condliffe R. Pulmonary arterial hypertension associated with congenital heart disease: classification and pathophysiology. J Congenit Cardiol. 2020;4(S1):1-7. doi:10.1186/s40949-020-00040-0
  11. Knafl D, Gerges C, King CH, Humbert M, Bustinduy AL. Schistosomiasis-associated pulmonary arterial hypertension. Eur Respir Rev. 2020;29(155). doi:10.1183/16000617.0089-2019
  12. Martinho S, Adão R, Leite-Moreira AF, Brás-Silva C. Persistent pulmonary hypertension of the newborn: pathophysiological mechanisms and novel therapeutic approaches. Front Pediatr. 2020;8:342. doi:10.3389/fped.2020.00342

Reviewed by Kyle Habet, MD, on 7/1/2021.

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