BACKGROUND: Little is known concerning the degree to which initiation of 
sildenafil for pulmonary arterial hypertension (PAH) impacts patterns of 
healthcare utilization and costs.
METHODS: Using a large US health insurance claims database, we identified all 
patients with evidence of PAH (ICD-9-CM diagnosis codes 416.0, 416.8) who 
received sildenafil between 1/1/2005 and 9/30/2008. Date of the first-noted 
prescription for sildenafil was designated the "index date," and claims data 
were compiled for all study subjects for 6 months prior to their index date 
("pretreatment") and 6 months thereafter ("follow-up"); patients with incomplete 
data during either of these periods were excluded. Healthcare utilization and 
costs were then compared between pretreatment and follow-up for all study 
subjects.
RESULTS: A total of 567 PAH patients were identified who began therapy with 
sildenafil and met all other study entry criteria. Mean (SD) age was 52 (10) 
years; 73% were women. Healthcare utilization was largely unchanged between 
pretreatment and follow-up, the only exceptions being decreases in the mean 
number of emergency department visits (from 0.7 to 0.5 per patient; p<0.01) and 
the percentage of patients hospitalized (from 35% to 29%; p=0.01). The mean cost 
of all PAH-related medication was $7139 during pretreatment and $14,095 during 
follow-up (sildenafil cost during follow-up= $5236); exclusive of PAH-related 
medications, however, total healthcare costs decreased modestly (from $30,104 to 
$27,605) (p<0.01 for all comparisons).
CONCLUSIONS: The cost of sildenafil therapy may be partially offset by 
reductions in other healthcare costs.