Real‐world clinical practice of pulmonary arterial hypertension in Japan: Insights from a large administrative database

Pulmonary arterial hypertension (PAH) is a fatal disease that often occurs at an early age. In recent years, aggressive treatment with multiple drugs from the early‐stage diagnosis is expected to improve the prognosis. Indeed, a high rate of initial combination therapy and excellent treatment outcomes have been reported from specialized centers for PAH in Japan. However, information on PAH epidemiology, including non‐PAH specialized centers in Japan, is unclear. To address the above, we conducted a retrospective observational cohort study from April 2008 to September 2020 using real‐world evidence from a large‐scale administrative database (Medical Data Vision) to examine baseline characteristics, comorbidities, and treatment profiles of Japanese patients with PAH. Five hundred and eighteen patients with PAH (treatment‐naive PAH, age 67.2 ± 15.9) were identified through our comprehensive approach which combined PAH disease codes, medications, and diagnostic procedures. Moreover, we showed that a larger proportion of patients received monotherapy in their initial treatment (66%) compared to those receiving combination therapy (34%). During the 1‐year follow‐up after PAH diagnosis, 13% of patients increased their PAH medications while other patients either decreased their PAH medications (6%) or discontinued PAH treatment (27%). The 3‐ and 5‐year event‐free survival rates of all‐cause death were 72% and 64%, respectively. This is the first large‐scale administrative database study that provides insights into real‐world PAH management in Japan. This study highlighted a different PAH clinical landscape which included a larger portion of the elderly population, higher initial monotherapy treatment, and lower survival rates than previous studies.