Centers and participants

Centers were selected based on their treatment of patients with World Health Organization Group 1 PH (PAH) and further input from the CIPDR steering committee (with recommendations based on their expertise in this entity; no specific criteria were predefined for center selection or recommendations). The repository was designed to include a nationwide US cohort, to minimize potential regional bias. Details of participating centers are provided in Figure 1 and in the Supporting Information: Table S1. Central approval was obtained through the Western Institutional Review Board. In addition, all Pulmonary Hypertension Association–accredited centers obtained approval for the TRIO CIPDR protocol from their local institutional review board.

The target sample size for TRIO CIPDR was predefined as 1000 patients with PAH. To facilitate enrollment, specialty pharmacy data corresponding to each center was used to identify patients likely to qualify for the data collection, and to pre‐populate qualification forms. However, no specialty pharmacy data (used for patient eligibility assessment) were captured in the repository itself; data for the repository were taken solely from each center's electronic medical records. Each center reviewed and identified patients who met the TRIO CIPDR inclusion criteria. Qualifying patients had a diagnosis of World Health Organization Group 1 PH (PAH); were ≥18 years; were prescribed PAH‐specific medications; and had documented mean pulmonary arterial pressure ≥25 mmHg, pulmonary capillary wedge pressure ≤15 mmHg, and pulmonary vascular resistance ≥3.0 Wood units at rest, as determined by right heart catheterization (RHC). RHC parameters were aligned with criteria for PAH at the time the repository was established ¹¹ and before recent updates of PH/PAH diagnostic thresholds. ¹² Exclusion criteria included diagnosis of World Health Organization PH Group 2, 3, 4, or 5; absence of documentation of hemodynamic and clinical criteria for PAH; participation in a clinical trial; and age <18 years. Only patients with the required demographic, clinical, and hemodynamic data, as well as corresponding drug‐dispensing data, available from January 2015, were included in TRIO CIPDR.

Patients were enrolled in TRIO CIPDR using a pragmatic approach. Patients confirmed by their physician to meet the predefined inclusion criteria were enrolled sequentially in TRIO CIPDR until the predefined sample size (N = 1000) was reached. The site treating physician made the decision about which patients were enrolled and was not required to provide a reason why a patient was not included.