IMPORTANT INFORMATION CONCERNING USE OF NAMCS AND NHAMCS DRUG DATA
NOTE: The materials in this folder pertain to the National Drug Code
Directory (NDC) therapeutic classification system used with NAMCS and
NHAMCS data prior to the 2006 surveys. They are included here in case
researchers wish to do analysis on years of drug data prior to 2006
ONLY.
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For researchers trending across years INCLUDING 2006, please DO
NOT use these materials; instead refer to the document: "Trend Analysis
Using NAMCS and NHAMCS Drug Data" and the programs and files found at:
ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentation/NAMCS/drugs/ or
ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentation/NHAMCS/drugs/
Note that the files and programs are the same for NAMCS and NHAMCS.
They are put in both folders simply for the convenience of data users.
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It is important for researchers to note that, starting with the 2006
NAMCS and NHAMCS, a new classification system was adopted to code the
characteristics of drugs reported on the Patient Record forms. The
NAMCS and NHAMCS no longer use the NCHS-developed 5-digit code to
classify drugs according to their generic components (the second coding
described above), nor do they use the National Drug Code Directory to
code therapeutic class. However, the first coding of the drug "as
written" using the NCHS-developed classification is still used.
Drugs are now coded in terms of their generic components and
therapeutic classes using Lexicon PlusĀ®, a proprietary database of
Cerner Multum, Inc., also used by the National Health and Nutrition
Examination Survey, NCHS. The Lexicon Plus is a comprehensive database
of all prescription and some nonprescription drug products available in
the U.S. drug market. For additional information on the Multum
Lexicon Drug Database, please refer to the following Web site:
http://www.multum.com/Lexicon.htm
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FOR THOSE ONLY USING DATA PRIOR TO 2006 who do not need to convert drug codes
and therapeutic classes to the system implemented with 2006 data, the following
information is relevant:
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The Ambulatory Care Drug Database underwent substantial revisions in
2002, as described in the 2002 NAMCS and NHAMCS Public Use Data File
Documentation. As part of our annual data processing, we add new drugs
and update the database as needed. Because of these revisions to the
file, and also because of the addition of a second and third
therapeutic class for each drug beginning in 2004, trend analysis with
survey data prior to 2002 becomes more problematic. We recommend that
researchers download the Drug Characteristics file (DRUGFILE-2004.DAT),
which is updated annually. The characteristics from this file can be
applied by matching on drug codes to previous years of data in order to
get the most accurate results when doing analysis of drug trends. We
have also prepared a SAS program (which can be adapted for use with
other software) (DRUGCHAR.SAS) to apply the new characteristics from
the most current version of the drug database to previous years of
data. This program will create a SAS dataset for you for each data
year you run it for. There is just one version of the Drug
Characteristics file and one version of the SAS program, which can be
used with both NAMCS and NHAMCS public use files. For the convenience
of data users, these have been placed in both the NAMCS and NHAMCS
dataset documentation areas of the FTP server. Please contact the
Ambulatory Care Statistics Branch at 301-458-4600 if you have
questions.