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.