LOW/HIGH Birth Weight Macro
                               Version 1.00
                           Leonard R. MacWilliam
              Manitoba Centre for Health Policy and Evaluation

                               April 22, 1997


This program is used to compute rates of LOW and HIGH BirthWeight babies
BY Region. By default, the program computes rates based on all SINGLETON
(i.e. single baby) births over the most recent 3 years of Manitoba data.
This can be modified with optional parameters: STARTYR - 2 digit value
representing the starting FISCAL year of hospital calims ; LASTYR - 2
digit number representing the end of the last FISCAL year (eg. 96 if
using 95/96 as the last fiscal year) of claims ; and NYRS - value
representing the number of FISCAL years of claims used.

The DEFAULT region is Regional Health Authority (RHA).


Macro Call:
   option implmac  nosource;
   %include '/home/lmacwil/healthstatus/concepts/_lowbwgt.mac' ;
   option source ;

 _lowbwgt   ;

Options:
     data= name of dataset(s) from which to extract newborn data
           (OPTIONAL, DEFAULT="cpe.hsp9394l cpe.hsp9495l cpe.hsp9596l")
           NOTE: if more than 1 year of cpe hospital datasets are
                 specified BE SURE to enclose them in quotes (") as
                 in the default example above.

     out= name of dataset to which the birth weight rates are written
      (OPTIONAL, DEFAULT=nb9395) NOTE: if you use a two level SAS name, eg.
          dsd.nb9395, then you must have a libname statement in your
          program before the macro call (eg. Libname dsd '/dsd1/roos5';)

     startyr= 2 digit value representing the beginning FISCAL YEAR from
             which to extract birth records. (OPTIONAL, default=93)

     nyrs= number of CALENDAR years of birth data to extract
           (OPTIONAL, default=3).    This parameter will
           cause the macro to extract  NYRS  FISCAL years of birth
           records starting at April. 1 of STARTYR .

     region= name af an area variable for which the macro will compute
             life expectancy values. (OPTIONAL, DEFAULT=RHA).
             Options are:
               RHA - Regional Health Authorities (see: _rha macro)
               WPGAREA - 9 Winnipeg Areas (see: _wpg_reg macro)
               PARHA - Physician Service Areas (see: _parha macro)
               _RANK_ - Winnipeg Urban Quintiles (see: _quint macro)

     debug=  Toggle debugging feature (=debug/=nodebug(default))


Example Calls:

Libname  dsd  'dsd1/lmacwil/rha97' ;
_lowbwgt;  startyr=91    out=dsd.nb9395
           nyrs=5
           debug=no  ;  * compute birth weight rates  per RHA using
                     * 5 fiscal yrs of births: 1 Apr. 1991 to 31 Mar. 1996 *;

_lowbwgt ; ** compute birth weight rates using the 3 most recent yrs of  *;
            * births:  1 Apr. 1993 to 31 Mar. 1996  BY  RHA         *;

_lowbwgt  out=dsd.nbwpgQ
          region=_rank_  ;
       ** compute birth weight rates  per Winnipeg Income
       ** Quintile, using the 3 most recent yrs of births. Save
       ** the results in a permanent SAS dataset

CAUTIONS:

GIVEN THE VERY SMALL FREQUENCY OF low (< 2500 grams) BIRTH WEIGHT
NEWBORNS (approximately 4 % of all singleton births) THE USER OF THIS
MACRO SHOULD ASCERTAIN THAT EACH REGION TO BE ANALYZED HAVE IN EXCESS
OF 1,000 BIRTHS IN ORDER TO OBTAIN "statistically stable" RESULTS FOR
LOW BIRTH WEIGHT NEWBORNS. IN MOST SITUATIONS THIS WILL MEAN USING
MORE THAN 1 YEAR OF NEWBORN DATA. IN THE CASE OF RHAs, YOU WILL NEED A
MINIMUM OF 3 YEARS OF DATA. FOR SMALLER AREAS (eg. PARHAs) I WOULD
RECOMMEND 5 YEARS OF DATA. FOR A WINNIPEG 9 SUB-AREA OR QUINTILE ANALYSIS
1 YEAR OF DATA MAY BE SUFFICIENT HOWEVER 2 YEARS WOULD BE BETTER.

NOTES:

BY default, this macro creates a temporary SAS dataset, named nb9395
containing birth rates per 1,000 SINGLETON newborns (i.e. twin births,
triplets, etc. are excluded) by Birth Weight (1-LOW:< 2500 g.
2- 2500-4000 grams, 3-HIGH:> 4000 g.)
This macro uses the POP_RATE macro to compute  sex standardized rates,
thus all of the variables produced by the POP_RATES macro will be found
in the nb9395 (&out) dataset.
The variable which counts the number of births is named BIRTH, thus the
variable names produced by the POP_RATES macro will be C_BIRTH (Crude
Birth Rate), O_BITRH (observed no. of births), etc.
The DEFAULT region variable used is: Regional Health Authority (RHA).

By default the macro extracts death data from:
  cpe.hsp9394g  cpe.hsp9495  cpe.hsp9596 .

The macro uses the _RHA macro to compute values for a region var. (RHA).
NOTE that it has collapsed the three Winnipeg areas (H, I, J) into a
single value K.  Also, it uses the _WPG_REG macro to create a second
area variable, named WPGAREA, containing the 9 Winnipeg sub-regions.
And, the _PARHA macro is used to produce a third area variable, named
PARHA, containing the 60 Physician Service areas contained within the
Regional Health Authorities.  A fourth area variable (named _RANK_) is
computed using the _QUINT macro. It contains the Income Quintile values.
PLEASE NOTE: if the region=_rank_ option is specified  macro will
compute life expectancy values for ONLY The Winnipeg URBAN Quintile
Population.