How common is PAH?

Although Pulmonary arterial hypertension (PAH) is a rare disease, with an estimated prevalence of 30-50 cases per million,¹ the prevalence of Pulmonary Arterial Hypertension (PAH) in certain at-risk groups is substantially higher. For example, in HIV-infected patients the prevalence is 0.5%,² in patients with sickle cell disease the prevalence is 20-40%³ and in patients with systemic sclerosis the prevalence has been reported to be up to 38%.⁴

Idiopathic Pulmonary Arterial Hypertension (PAH) is more common in young women with a mean age of diagnosis of 36 years. However it can occur at any age.⁵ Idiopathic Pulmonary Arterial Hypertension (PAH) is twice as common in women as in men.^5,6 Although the true relative prevalence of IPAH, FPAH and APAH are unknown, it is likely that IPAH accounts for at least 40% of cases, and APAH for most of the remaining cases.^7,8

Due to the non-specific nature of the symptoms, Pulmonary Arterial Hypertension (PAH) is most frequently diagnosed when patients have reached an advanced stage of disease (WHO Functional Class III and IV),⁸ suggesting that the true prevalence may be higher than documented in the literature.

References
1. Peacock AJ. Treatment of pulmonary hypertension. BMJ 2003; 326: 835-6
2. Speich R, Jenni R, Opravil M et al. Primary pulmonary hypertension in HIV infection. Chest 1991;100:1268-71.
3. Lin EE, Rodgers GP, Gladwin MT. Hemolytic anemia-associated pulmonary hypertension in sickle cell disease. Curr Hematol Rep 2005;4(2):117-25
4. McGoon M, Gutterman D, Steen V et al. Screening, early detection, and diagnosis of pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines. Chest 2004; 126(1 Suppl):  14S-34S
5. Gaine SP, Rubin LJ. Primary Pulmonary Hypertension. Lancet  1998; 352: 719-25
6. Lane KB, Machado RD, Pauciulo MW et al. Heterozygous germline mutations in BMPR2, encoding a TGF-beta receptor, cause familial primary pulmonary hypertension. The International PPH Consortium. Nat Genet 2000;26(1):81-4.
7. Humbert M, Simmoneau G. Pulmonary arterial hypertension. Orphanet encyclopaedia, Nov 2004.
8. Humbert M, Sitbon O, Chaouat A et al. Pulmonary Arterial Hypertension in France: Results from a National Registry. Am J Respir Crit Care Med 2006; 173(9): 1023-30.