topic Re: "if and THEN" conditional programming. in SAS Procedures

"if and THEN" conditional programming.

Achieng — Thu, 15 Feb 2018 07:07:50 GMT

"if and THEN" conditional programming.

Dear Community,

I hope this email finds you well. Thank you for all your help. I have learned a lot from the other responses.

I need a little help with some programming,

I am analyzing data and would like to meet some conditions.

I have a group of metabolic syndrome participants and non-metabolic one. I would like to classify them into metabolically healthy normal weight (MHNW), metabolically Unhealthy normal weight (MUNW) and metabolically healthy overweight (MHO) and metabolically unhealthy overweight (MUO).

data Alisama;set Alisama;
log_waist=log(Waistcm);/**add log forthe other variables/
/*do it with non normally distributed outcomes*/
log_CRP=log(CRP_High_S);
label T2DMMetS_ALL ="T2DM";
met_s=0;
if MetS_Total>=3 then met_s=1;
array score score0-score5;
do i=0 to 5;
score[i]=0;
end;
     if Gender_Code_2005=1 & Waist_2015>=94                                       then score1=1;*codes for men;
else if Gender_Code_2005=2 & Waist_2015>=80                                       then score1=1;*codes for women;

if TRIG2015>=1.7                                                            then score2=1;

     if Gender_Code_2005=1 & HDLC32015<=1                                        then score3=1;*codes for men;
else if Gender_Code_2005=2 & HDLC32015<=1.3                                      then score3=1;*codes for women;

     if SBPOmr2015>=130 or DBP2015>=85 or HT_MED2015=1     then score4=1;*codes for men;
	 if Glucose2015>=5.6                          or DIAB_MED2015=1 then score5=1;*codes for men;
MetS_Total=sum(of score0-score5);
met_s2=0;if MetS_Total>=3 then met_s2=1;

run;

SAS Output

met_s2 Frequency Percent CumulativeFrequency CumulativePercent01

188	69.63	188	69.63
82	30.37	270	100.00

SAS Output

score_MS Frequency Percent CumulativeFrequency CumulativePercent012345

24	8.89	24	8.89
85	31.48	109	40.37
79	29.26	188	69.63
52	19.26	240	88.89
27	10.00	267	98.89
3	1.11	270	100.00

I have already classified the metabolical syndrome and the above are the numbers.

However, whatever I do, I have failed to get the qualifications mentioned above right,

The problem is here

data ALLMH05TO15; set ALLMH05TO15;
  if BMI_2015 <=24.99999 & met_s2=0                    then MHNW=0;
if BMI_2015 >=25.0 & met_s2=0                        	then MHO=1;
run;

if BMI_2015 <=24.99999 & met_s2=1     				then MUNW=0;
 if BMI_2015 >=25.0 & met_s2=1  						then MUO=1;

run;

SAS Output

The FREQ Procedure

These are the results I am generating thing which is not adding up.

SAS Output

The FREQ Procedure

MHNWMHNW Frequency Percent CumulativeFrequency CumulativePercent01

171	63.33	171	63.33
99	36.67	270	100.00

MHO Frequency Percent CumulativeFrequency CumulativePercent1Frequency Missing = 218

100.00

MUNW Frequency Percent CumulativeFrequency CumulativePercent01Frequency Missing = 188

20	24.39	20	24.39
62	75.61	82	100.00

MUO Frequency Percent CumulativeFrequency CumulativePercent1Frequency Missing = 208

100.00

So I tried another method..

data ALLMH05TO15;set ALLMH05TO15;


 if BMI_2015<=24.99999 & MetS_Total_2015=0                        then MHNW=0;
 if BMI_2015<=24.99999 & MetS_Total_2015=1     						then MHNW=0;
 if BMI_2015<=24.99999 & MetS_Total_2015=2     						then MHNW=0;
 if BMI_2015<=24.99999 & MetS_Total_2015>=3     						then MUNW=1;


if BMI_2015 >=25.0 & MetS_Total_2015=0                        	then MHNW=1;
if BMI_2015 >=25.0 & MetS_Total_2015=1  							then MHNW=1;
if BMI_2015 >=25.0 & MetS_Total_2015=2  							then MHNW=1;

if BMI_2015 <=24.99999 & MetS_Total_2015>=3                           then MUNW=0;
if  BMI_2015 >=25.0 & MetS_Total_2015>=3                             then MUNW=1;

run;

These are the results

SAS Output

MHNWMHNW Frequency Percent CumulativeFrequency CumulativePercent01

171	63.33	171	63.33
99	36.67	270	100.00

MUNW Frequency Percent CumulativeFrequency CumulativePercent01Frequency Missing = 188

20	24.39	20	24.39
62	75.61	82	100.00

So I don't know what I am doing wrong,

I would like to get a column with the exact numbers. I understand the last results, but not the first. Please help.

Worried Ph.D. student

New SAS user,

Re: "if and THEN" conditional programming.

RW9 — Thu, 15 Feb 2018 09:00:39 GMT

I cannot tell from what you post, as always, first step is to provide test data in the form of a datastep.

I suspect your if statement is not capturing all eventualities for instance:

if BMI_2015<=24.99999 & MetS_Total_2015>=3     						then MUNW=1;


if BMI_2015 >=25.0 & MetS_Total_2015=0

What if bmi_2015 = 24.999991? Neither of those if statements would trigger. One way to capture all would be:

if bmi_2015 <= 24.99999 then do;
  ...
end;
else do;
  ...
end;

And nestle your statements. Also, your numbers may contain a very small fraction of a number (due to storage on the machine), so rounding the value may also help. Also, avoid coding in mixed code and use indents so its easy to read the code.

Re: "if and THEN" conditional programming.

Achieng — Thu, 15 Feb 2018 12:26:55 GMT

Der superuser, nice to hear from you.

Apologies for not attaching sample data. Plese, find attached.

Please find attached my sample data set.

Re: "if and THEN" conditional programming.

Achieng — Thu, 15 Feb 2018 12:37:42 GMT

Dear Superuser, sample data attached. Apologies for not attaching earlier. Thank you.

Re: "if and THEN" conditional programming.

Achieng — Thu, 15 Feb 2018 12:54:25 GMT

You may need to run this step first. Thank you very much for your help.

data Sample_Ac;set Sample_Ac;
met_s=0;
if MetS_Total>=3 then met_s=1;
array score score1-score5;
do i=1 to 5;
score[i]=0;
end;

if Gender_Code_2005=1 & Waist_2015>=94                then score1=1;*codes for men;
else if Gender_Code_2005=2 & Waist_2015>=80           then score1=1;*codes for women;

if TRIG2015>=1.7       								  then score2=1;

if Gender_Code_2005=1 & HDLC32015<=1                  then score3=1;*codes for men;
else if Gender_Code_2005=2 & HDLC32015<=1.3           then score3=1;*codes for women;

if SBPOmr2015>=130 or DBP2015>=85 or HT_MED2015=1     then score4=1;
if Glucose2015>=5.6      or T2DM2015=1 				  then score5=1;

score_MS=sum(of score1-score5);
met_s2=0;if score_MS>=3 then met_s2=1;
run;


Proc freq data = Sample_Data;   tables met_s2  score_MS;
run; 


data Sample_Ac; set Sample_Ac;
rename score_MS= MetS_Total_2015;*rename old=new*;
run;

Re: "if and THEN" conditional programming.

RW9 — Thu, 15 Feb 2018 14:12:35 GMT

Sorry, you misunderstand, I don't want to open Excel files, nor do I want to write import programs to try to deal with those or guess your data. I want you to provide, in a datastep, some test data which shows what you have, what the structure of the dataset is, and what you want out at the end. Follow this post if need:

https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-data-AKA-generate/ta-p/258712

Re: "if and THEN" conditional programming.

ballardw — Thu, 15 Feb 2018 17:19:29 GMT

With appropriate formats for continuous variables this will create a grid that shows which combinations of values were assigned which score and may help find missing or overcounts

proc tabulate data= Alisama;
   class Gender_Code_2005   Waist_2015  TRIG2015 HDLC32015
   SBPOmr2015 DBP2015 HT_MED2015 Glucose2015   DIAB_MED2015 /missing;
   /* your continuous variables should have a format to indicate the >, < or
      the range of interest and have a corresponding
      format assignment statment here
   */
   var score0 - score5;
   table  Gender_Code_2005 * Waist_2015 * TRIG2015 HDLC32015*
      SBPOmr2015* DBP2015* HT_MED2015 Glucose2015   *DIAB_MED2015 ,
      (score0 score1 score2 score3 score4 score5)*sum=''
      / misstext=' '
   ;
run;

And I would be very cautious of habitual use of

data Alisama;set Alisama;

as that has a potential for creating all sorts of chaos as testing this sort of recode if any of the independent variables (waist for instance) has adjustment code.

Re: "if and THEN" conditional programming.

Achieng — Mon, 19 Feb 2018 08:22:55 GMT

Hello Superuser,
I have been unable to create the data set you wanted,
I am using SAS 9.4. I don't know what I am doing wrong,
have 270 observations and 298 variables.
Please help.

I have not resolved the original problem I posted last week.
Thank you.

Re: "if and THEN" conditional programming.

RW9 — Mon, 19 Feb 2018 09:09:14 GMT

There is nothing I can do, I cannot see your data to tell you where you are going wrong. All I can repeat is that this:

 if BMI_2015<=24.99999 & MetS_Total_2015>=3 then MUNW=1;
if BMI_2015 >=25.0 & MetS_Total_2015=0 then MHNW=1;

Does not cover all evenetualities - 24.999991 for instance would get flagged. I have suggested other methods to cover all eventualities, have you tried these?

if bmi_2015 <= 24.99999 ... do;
  ...
end;
else do;
   ...
end;

Without information on what you are using I cannot do anything.

Re: "if and THEN" conditional programming.

Achieng — Mon, 19 Feb 2018 15:21:05 GMT

Hello Superuser,

I don't know what I am doing wrong, I about to die, I have been unable to solve this problem since last week.

I have tried what you advised. So I went ahead and categorized the two BMI categories.

data ALLMH05TO15; set ALLMH05TO15;

 if BMI_2015 <= 24.794988736 	then BMICAT=0;
if  BMI_2015 => 25.004109139	 	then BMICAT=1;


run;

I then went ahead to classify my metabolic syndrome.

Metabolic healthy with Normal weight (MHNW)

Metabolically healthy overweight/obese (MHO)

Metabolically Unhelathy Normla weight (MUNW)

Metabolically unhealthy overweight/obese (MUO)

in other words, I need to combine the MetS_total_2015 and he BMI category which I have included up there to meet the conditions for the MHNW, MUNW, MHO, MUO.

SAS Output

MetS_Total_2015 Frequency Percent CumulativeFrequency CumulativePercent012345

24	8.89	24	8.89
85	31.48	109	40.37
79	29.26	188	69.63
52	19.26	240	88.89
27	10.00	267	98.89
3	1.11	270	100.00

I have attempted to classify

data ALLMH05TO15; set ALLMH05TO15;

if MetS_Total_2015 <= 2	& BMICAT=0 		then MHNW=0;
if MetS_Total_2015 =>3 	& BMICAT=0  	then MUNW=0;


if MetS_Total_2015 <= 2 & BMICAT=1		then MHNW=1;
if MetS_Total_2015 =>3 	& BMICAT=1  	then MUNW=1;

run;

These are the results I am getting

SAS Output

MHNWMHNW Frequency Percent CumulativeFrequency CumulativePercent01

155	57.41	155	57.41
115	42.59	270	100.00

MUNW Frequency Percent CumulativeFrequency CumulativePercent01Frequency Missing = 188

20	24.39	20	24.39
62	75.61	82	100.00

The second set of results are correct (MUNW). however, the first set (MHNW) is wrong, it is including all the data to give me a total of 270, yet I should have a total of 188 and not 270. Please, I hope someone can understand my problem.

I have a feeling the problem lies in the metabolic syndrome category... but I keep getting an error,

1024  data ALLMH05TO15; set ALLMH05TO15;
1025  met_s=0;
1026  if MetS_Total>=3 then met_s=1;
1027  array score score0-score5;
1028  do i=0 to 5;
1029  score[i]=0;
1030  end;
1031       if Gender_Code_2005=1 & Waist_2015>=94                                       then
1031! score1=1;*codes for men;
1032  else if Gender_Code_2005=2 & Waist_2015>=80                                       then
1032! score1=1;*codes for women;
1033
1034  if TRIG2015>=1.7                                                            then score2=1;
1035
1036       if Gender_Code_2005=1 & HDLC32015<=1                                        then score3=1
1036! ;*codes for men;
1037  else if Gender_Code_2005=2 & HDLC32015<=1.3                                      then score3=1
1037! ;*codes for women;
1038
1039       if SBPOmr2015>=130 or DBP2015>=85 or HT_MED2015=1     then score4=1;*codes for men;
1040       if Glucose2015>=5.6                          or DIAB_MED2015=1 then score5=1;*codes for
1040! men;
1041  MetS_Total=sum(of score0-score5);
1042  met_s2=0;if MetS_Total>=3 then met_s2=1;
1043
1044  run;

ERROR: Array subscript out of range at line 1029 column 1.

I have no help, I am depending on all of you;).

Thank you

Achieng

Re: "if and THEN" conditional programming.

Achieng — Fri, 23 Feb 2018 11:01:19 GMT

Hi everyone,

I managed to resolve the issues. I had to go manually to the data set to find out what was wrong,

I found that some of the variables had Metabolic syndrome classification but were missing BMI values, and others had the BMI status but were missing the metabolic system classification. Once I deleted these, I was able to resolve the problem.

Thank you

very kind regards