OBJECTIVE: To explore treatment patterns and resource utilization and cost for 
subjects with pulmonary arterial hypertension (PAH).
RESEARCH DESIGN: Retrospective claims database analysis of 706 patients with PAH 
enrolled in a large, geographically diverse US managed-care organization.
RESULTS: In the final sample of PAH patients treated with bosentan (n=251) or 
sildenafil (n=455), average age was 57 years, 86% of patients were commercially 
insured, and 52% of patients were male. Gender distribution varied significantly 
across subgroups, with a lower proportion of males in the bosentan (30%) 
subgroup compared with the sildenafil group (64%) (p<0.001). Average baseline 
Charlson comorbidity score was 2.4. Average numbers of fills per month were 0.8 
and 0.4 for bosentan and sildenafil patients, respectively (p<0.001). Over 80% 
of patients received only one PAH treatment in the first 90 days following the 
index date, with 28% of bosentan and 13% of sildenafil patients receiving 
combination therapy (p<0.001). Over one-third of bosentan patients and 
one-quarter of sildenafil patients experienced a dose increase in the follow-up 
period (p=0.009). Sixteen percent of sildenafil patients experienced a dose 
decrease in the follow-up period, while a smaller proportion of patients 
receiving bosentan (4%) experienced a dose decrease (p<0.001). On average, 
number of PAH-related per subject per month (PSPM) inpatient stays and emergency 
department visits and PSPM length of inpatient stays were statistically similar 
between the subgroups. PAH-related PSPM healthcare costs were high for both 
subgroups, with average monthly costs of $5,332 and $3,632 among bosentan and 
sildenafil patients, respectively (p=0.003). Differences in total costs were 
driven mainly by differences in pharmacy expenditures.
CONCLUSIONS: Of the oral agents approved for treating PAH at the time of this 
study, sildenafil was most commonly prescribed as index therapy and was also 
associated with the lowest costs, largely due to significantly lower pharmacy 
costs. This study is characterized by limitations inherent to claims database 
analyses, such as the potential for coding errors and lack of information on 
whether a drug was taken as prescribed. Furthermore, PAH severity (WHO 
functional class) was not assessed.