sanofi-aventis Managed Care Digest Series®
Therapeutics Trends Summary™ 2008
Data Collection
Through agreements with a variety of data providers, the Verispan data warehouse receives
between 1.5 billion to 2 billion prescription transactions and 425 million medical
claims (both provider and hospital) annually—a total of 8 billion prescription claims
representing nearly 200 million unique patients. Verispan’s prescription data include samples
from nearly 59,000 pharmacies (a near census) in the United States and include cash,
Medicaid and commercial transactions.
Verispan’s warehouse contains data as reported on NCPDP (prescription),
CMS 1500 (physician office claims) and UB-92 (hospital claims) forms.
All activity is linked and integrated by Verispan’s unique identifier.
CMS 1500 and UB-92 claims contain ICD-9 (diagnosis) and CPT-4 (procedure)
activity that can be linked across prescription activity, and on a cross section
of patients. Other valuable medical metrics include date of service, discharge dates,
and location of care (office, ER, etc.).
Prescription Projections
Verispan receives prescription information from virtually every retail pharmacy
in the U.S. Verispan receives all prescriptions from about one-third of the stores
and an average of approximately one-third of prescriptions for the remaining stores.
Each store has a prescription sequence numbering system that is used by Verispan to
count the missing prescriptions in stores where Verispan receives a sample of their data.
This allows Verispan to track the size of every store in the U.S.
Projections are stratified by payment type, class of trade and geography. In the first phase of projection Verispan uses 814 projection territories aligned to balance coverage proportional to prescribing activity. These territories are stratified by payment type and the sample is expanded
to the universe, by strata, in each territory. In the second phase of projection Verispan stratifies the country by census division and class of trade. There are four store types that define the
classes of trade: Pharmacy Chains, Mass Merchandisers with Pharmacies, Food Stores with Pharmacies, and Independent Pharmacies. Each of the nine census divisions is split into four
store types. The sample in each of these 36 strata is expanded to the universe. In the
third phase of the projection, Verispan reconciles the results of the first two phases to produce
a single projection factor for each claim. This factor is used to project prescriptions and patients filling a prescription.
The projection factors calculated above are used to project prescriptions and patients for
each prescriber in all sales territories. Regional and national projections are created by
rolling up from the prescriber to the geographic area of interest.
Medical Data Projections
Monthly medical projection factors are calculated by specialty at the national level.
Physician specialties are classified into 17 related specialty groups. Each month,
the number of office-based physicians in the U.S. and the number of physicians in
Verispan’s medical database are estimated by specialty. Projection factor is the
inverse of the specialty coverage rate (size of the physician universe/size of the sample).
For specialties with large projection factor variance over time (specialties of low
coverage rate or small size), specialty group projection factors are used to stabilize
the projection. Specialty projection factors are applied to claims according to
date and physician specialty.
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