Pulmonary arterial hypertension (PAH) is an incurable, progressive disease of the pulmonary vasculature that leads to right heart failure and, ultimately, death. Significant advances in our understanding of the pathogenesis and pathobiology of the disease have led to the development of novel therapies that, in turn, have offered improvement in outcomes. However, mortality remains unacceptably high for patients with this disease. In addition, PAH is associated with significant morbidity. Complicated medication delivery and adverse effect profiles, disease progression necessitating hospitalization, and effects on social and emotional functioning all contribute to a high burden of disease. However, while hospitalizations for exacerbations of disease are common and appear to be associated with long-term outcomes in PAH, 1 little is known about the characteristics, effect on short-term outcomes, and costs associated with these hospitalizations.In this issue of JAMA Cardiology, Anand and colleagues 2 make an important first step to answer some of these questions. Using the National Inpatient Sample database, a Healthcare Utilization Project database sponsored by the Agency for Healthcare Research and Quality, the authors examine trends in hospitalization rates for patients with PAH between 2001 and 2012 and note some surprising and expected findings. While the admission rates for PAH decreased by 58% over the study period, the overall cost per hospitalization increased by more than 2-fold, even when adjusting for inflation. The authors speculate that rise in costs is related to the increased acuity of illness in those patients with PAH who are hospitalized; as outpatient care has improved, patients admitted to the hospital are generally more sick. This assertion is supported by the reported increased prevalence of significant comorbidities, such as acute kidney injury (more than 3-fold increase) and acute respiratory failure (more than 4-fold increase), that would potentially increase costs among hospitalized patients with PAH. While this is a reasonable conclusion, other factors that were not considered may also contribute to increased costs. Until November 2001, the only available therapy for PAH was intravenous epoprostenol, a therapy that requires continuous infusion through a centrally placed catheter and necessitates expert medical care, including hospitalization, to initiate. Despite being the only therapy that has demonstrated a survival benefit in a clinical trial, these aforementioned factors likely contribute to its underutilization in the United States. 3 By 2012, 7 additional therapies, including 3 oral agents and 2 inhaled agents, were available. While this represents an advance in the therapeutic armamentarium for PAH, the cost of these agents and the increasing use of combination therapy is considerable, both in the inpatient and outpatient settings. 4