OBJECTIVES: To describe treatment patterns and healthcare burden among 
individuals with suspected pulmonary arterial hypertension (PAH), as identified 
through a practice guideline-based healthcare claims algorithm.
METHODS: Adults with evidence of PAH from 1 January 2004 (commercial and 
Medicaid) or 1 July 2006 (Medicare Advantage) through 30 June 2008 were 
identified. Given the lack of an ICD-9 code for PAH, an algorithm was developed 
requiring: (1) ≥ 1 claim for PAH medication (index date); (2) ≥ 1 claim with a 
pulmonary hypertension diagnosis code in the 6-month pre-index period (baseline) 
or within 90 days post-index; (3) a right heart catheterization or pulmonary 
hypertension-related inpatient stay during baseline or within 90 days 
post-index; and (4) continuous health plan enrollment for 6 months pre-index and 
≥ 6 months post-index. Patients with PAH-specific medications during baseline 
were excluded. Treatment patterns, healthcare utilization, and costs were 
assessed during the period ending with the earlier of health plan disenrollment 
or 31 December 2008.
RESULTS: Among the 521 included patients, 69% were female. Most patients (94%) 
initiated treatment with monotherapy (most commonly sildenafil or bosentan), and 
12.7% of all patients augmented their therapy by the end of the observation 
period. The medication possession ratio was 0.96 each for ambrisentan (SD=0.04), 
bosentan (SD=0.04), and sildenafil (SD=0.05). Overall, 72.6% of patients 
discontinued therapy with a mean of 149 (SD=170) days until discontinuation. A 
mean (SD) of 2.14 (1.82) all-cause office and 1.64 (1.98) outpatient visits 
occurred per patient per month. Mean PAH-related healthcare costs were $6617 per 
patient per month, comprising 71% of all-cause costs. The guideline-based 
algorithm may not have perfectly captured patients with PAH.
CONCLUSIONS: Patients with suspected PAH were likely to initiate treatment with 
oral monotherapy, had high compliance rates, and received close ambulatory 
follow-up. PAH-related costs constituted the majority of all-cause healthcare 
costs.