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 PlusŪ, 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.