Factors influencing treatment decisions in patients with pulmonary arterial hypertension.

Background: A large proportion of patients with pulmonary arterial hypertension (PAH) is treated with monotherapy although current treatment guidelines emphasize the importance of combination therapies to achieve the treatment goals. Because the reasons for physicians' treatment decisions in routine clinical practice are not well understood, factors influencing these decisions were investigated. Methods: In this multicentre, non-interventional study, 79 patients who started PAH therapy ≤12 months prior to study inclusion were enrolled. Data available per routine clinical practice were collected. Furthermore, physician's rationale for treatment decision was assessed. All analyses were descriptive. Results: Patients' mean age was 64 years. Most patients were female (57.0%) with idiopathic PAH (76.0%) and had ≥5 comorbidities (64.6%). At therapy start the significant reasons for choosing combination therapy or monotherapy were patient's risk (81.5%; Odds ratio, OR: 12.38, p=0.0227) and comorbidity status (56.7%; OR: 0.07, p=0.0004), respectively. The proportion of patients receiving combination therapy increased from 45.6% at therapy start to 78.4% at month 24. Concomitantly, the percentage of low-risk patients increased from 14.5% to 35.1%. A significant greater percentage of patients on initial combination therapy achieved an improvement of World Health Organization functional class (85.2% and 50.0%, respectively; OR: 5.75, p=0.0357) between therapy start and end of observation. A low-risk status was achieved by 27.3% and 50.0% of patients on monotherapy and combination therapy, respectively. Discussion: Risk and comorbidity status are the key factors for physicians' choice of treatment regimen. Findings from the study suggest that patients on initial combination therapy could potentially improve their clinical status more effectively, even when they have comorbidities.