Pulmonary arterial hypertension in the USA: an epidemiological study in a large insured pediatric population

Pulmonary arterial hypertension (PAH) is rare in children and few data are available in a pediatric general population. This study aims to calculate the annual incidence and prevalence of PAH and to describe these children in a large US population of patients aged under 18 years. Using the US MarketScan claims database we identified 695 children with PAH in 2010–2013. We calculated annual incidence rates and prevalence overall, by age and PAH type (idiopathic and non-idiopathic) using Byar’s method. We also described characteristics, co-morbidities, treatment patterns, and diagnostic procedures for these children. In 2010–2013, the annual incidence rates of PAH per 1,000,000 children-years was in the range of 4.8–8.1; 0.5–0.9 for idiopathic PAH and 4.3–7.3 for non-idiopathic PAH. The annual prevalence of PAH was in the range of 25.7–32.6 per 1,000,000 children; 4.4–6.0 for idiopathic PAH and 21.3–27.0 for non-idiopathic PAH. Incidence rates and prevalence were highest in children under age 2 years. Around 36% of affected children were born prematurely. Most (75%) had some type of congenital heart defect and 13% had Down’s syndrome. Most patients received PAH monotherapy (83%), while 13% received dual therapy. Phosphodiesterase type 5 inhibitors were the most commonly used treatments. Around 92% had at least one echocardiogram and 37% a right heart catheterization. PAH is very rare in children especially in the absence of etiological factors such as congenital heart defects. A large proportion of diagnoses in children seem to be based on echocardiography rather than right heart catheterization.