Conference: 2010 International PHA Conference and Scientific Sessions
Release Date: 06.24.2010
Presentation Type: Abstracts
Mychaskiw MA1, Berger A2, Mardekian J1, Oster G2
1. Pfizer, Inc., New York, NY, USA
2. Policy Analysis, Inc., Brookline, MA, USA
BACKGROUND: While randomized controlled clinical trials are considered a “gold standard” in establishing drug efficacy and safety, such trials are often limited in their ability to provide insight into “real-world” patterns and outcomes of treatment. The objective of this study was to examine patterns of therapy, healthcare utilization, and healthcare costs among PAH patients initiating therapy with sildenafil.
METHODS: Using a large administrative healthcare claims database, we identified all patients aged >=18 years with evidence of PAH (ICD-9-CM diagnosis codes 416.0, 416.8) and >=1 claims for sildenafil between June 1, 2005 and September 30, 2008. Date of the first-noted claim for sildenafil was designated the “index date,” and patients with <6 months of pre-treatment data were excluded. Patients were followed from their index date until health plan disenrollment or end of study (“follow-up”). Patterns of therapy with sildenafil were examined, including numbers of prescriptions and associated therapy-days, as well as compliance; the latter was measured using medication possession ratio (MPR) (ratio of total number of therapy-days to total number of days of follow-up). For the subgroup of patients with >=6 months of follow-up data, healthcare utilization and costs were compared between the 6-month period preceding and following the index date.
RESULTS: A total of 855 PAH patients were identified who began therapy with sildenafil and met all other study inclusion criteria. Mean age was 53 years; 69% were women. Thirty-two percent had comorbid lung conditions and 17% connective tissue disorders. Over a mean duration of follow-up of 423 days (median, 357 days), study subjects averaged 6 prescriptions for sildenafil spanning 209 therapy-days (mean MPR=0.78). Healthcare utilization was largely unchanged between the 6-month pre- and post-index periods. Mean costs of outpatient care decreased by $501 ($8,321 vs $7,820 during pre-index); mean total healthcare costs increased by $4,137 (95% CI: $38,815, $42,952), primarily due to increased costs of PAH-related pharmacotherapy (including sildenafil) (p<0.01 for all comparisons).
CONCLUSIONS: PAH patients initiating sildenafil therapy are relatively compliant with treatment. While healthcare utilization is largely unchanged following initiation of sildenafil therapy, total healthcare costs increase, primarily due to costs of PAH-related pharmacotherapy. Further research is needed to better understand the “real-world” impact of sildenafil on patient health outcomes.