Download - United States Renal Data System

There are two parts to the ‘data=’ expression. The first is the directory location, defined by the LIBNAME, and the second is the
dataset name. The first part (directory location) implies that the dataset is permanent. Later examples do not include this part,
and the datasets you create will disappear when you leave SAS. To permanently save a dataset, the first part of the expression
must be included.
SAS Formats for USRDS data
Information in a dataset may be coded. Thus, the variable GENDER may have the values F, M, or U, where F is the coded value
for female, M is the value for male, and U is the value for unknown. Using one character instead of several saves disk storage,
but because the coded values are not always easy for users to understand, a format is assigned to translate them. Many variables
have been assigned formats by the USRDS.
In each program, SAS must be told where these formats are. Assume that the format catalog is in the directory C:\SAF. Then the
following SAS LIBNAME makes the formats accessible to your SAS programs.
LIBNAME LIBRARY ‘c:\saf’; * Directory location of format catalog;
The SAS keyword LIBRARY must be used because it tells SAS to look for formats in the directory, C:\SAF. Other methods can
accomplishing this, but not as easily. To bypass the use of formats, use the following two SAS statements before running any SAS
procedures:
LIBNAME LIBRARY;
OPTIONS NOFMTERR
Bypassing the use of formats allows you to see raw data instead of the formatted values, which may be useful when you need
to write SAS IF statements to control the flow of your program in a SAS data step. See Data Formatting for a tabular list of the
formats with their coded values.
Comment Lines
Comment lines in the SAS code look like this:
/* Comment line */
* Comment line;
These refer to any descriptive comment. The use of comments is optional but strongly recommended.
The SAF Directory
Throughout this section SAF has been used as the permanent SAS LIBNAME. It is assumed that all of the USRDS SAF datasets
and catalogs have been placed in this directory. If the datasets have been placed in the WINDOWS directory C:\SAF, then the
following SAS LIBNAME would point to the SAF datasets.
LIBNAME saf ‘c:\saf’;
Note: The datasets may be loaded into any directory, with the directory in the LIBNAME changed accordingly.
Examples
LIBNAME core_cd ‘C:\USRDS\CORE_CD\SAF’;
LIBNAME hosp_cd ‘C:\USRDS\HOSP_CD\SAF’;
LIBNAME in_cd ‘C:\USRDS\IN\SAF’;
LIBNAME cpm_cd ‘C:\USRDS\CPM\SAF’;
LIBNAME library ‘C:\USRDS\CORE_CD\SAF’;
Example 1: Incident Cohort
Create a patient cohort of incident patients from 1990 to 1999 to use in the examples that follow.
DATA inc90_99 (KEEP=usrds_id esrddate inc_year rxgroup);
SET core_cd.rxhist60;
BY usrds_id begdate;
FORMAT esrddate MMDDYY10.;
IF (FIRST.usrds_id) AND
(MDY(1,1,1990)