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deengyn
Obsidian | Level 7

I have looked at the previous posts, and have not been able to make sense of it. 

My data set is made of binary variables for a list of patient, disease, health characteristics (i.e. sex, diabetes, cardiac disease). Some are continuous variables (i.e. operation time in minutes) and others are categorical (i.e. tumour location).

The outcome was any complications post-op.

 

There is a total of 24 variables and 141 lines of data. 

Variable

Number of outputs available

Number of outputs missing

1.      Sex

141

0

2.      Thickness, categorical

141

0

3.      Histology, subtype

141

0

4.      Mitosis, binary

68

73

5.      Ulceration

78

63

6.      LVI

69

72

7.      Regression

63

78

8.      Smoker

116

25

9.      Diabetes

141

0

10.   Cardiac disease

141

0

11.   Hypothyroidism

141

0

12.   Staff/surgeon

141

0

13.   Presentation

141

0

14.   Indication

141

0

15.   Dissection type

139

2

16.   OP time

133

8

17.   Blood loss

91

50

18.   Number of drains left

141

0

19.   Duration of immobility

79

62

20.   Duration of post-op AB use

80

61

21.   Total hospital stay

80

61

22.   Total LN

140

1

23.   Total positive LN

141

0

24.   ER revisit

141

0


I've done correlation analyses; most had a RH0 of ~0.3-0.4. I couldn't perform VIF/tolerance tests, oddly. 

 

So to test the model, I did both univariate and multivariate analyses. An example of my code...

Where sex = 1 is male, where comp = 1 is any complication.

proc logisitic data = groin descending; 
class sex (ref = '0')/param = ref; 
model comp = sex/clodds = wald orpvalue; run;

And with each variable, the output states, "All Observations have the same response. No statistics are computed".

 

 

 

 

1 ACCEPTED SOLUTION

Accepted Solutions
ballardw
Super User

Your list of variables and those counts does not show COMP or anything that looks like the outcome "complications post-op".

You need to look closely at that variable and possibly in combination with your SEX variable to see if different levels of sex had any variation in Comp.

 

Such as

 

Proc freq data=groin;

   tables sex*comp/list;

run;

 

If there are no differences in COMP (when not missing) within levels of Sex then that is the reason.

View solution in original post

4 REPLIES 4
maguiremq
SAS Super FREQ

What does a PROC FREQ on `comp` tell you?

deengyn
Obsidian | Level 7

Thank you and good catch, it seemed like the code didn't run through for comp. And it was all 0's. 

ballardw
Super User

Your list of variables and those counts does not show COMP or anything that looks like the outcome "complications post-op".

You need to look closely at that variable and possibly in combination with your SEX variable to see if different levels of sex had any variation in Comp.

 

Such as

 

Proc freq data=groin;

   tables sex*comp/list;

run;

 

If there are no differences in COMP (when not missing) within levels of Sex then that is the reason.

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