minus sqrt calculation

[chinna0369]

Hi all, 

I have below derivation, can anyone help how can I implement this in sas?

Thanks,

Adithya

[Reeza]

Depends on your data set up to some degree. 

Assuming you have a data set with SCR, AGE and SEX as variables. 

if sex='Female' then eGFR = 194
                                                *(SCR**(1.094))
                                                 *(AGE**(-0.287))
                                                 *0.739;
else if sex = 'Male' then eGFR = 194
                                                *(SCR**(1.094))
                                                 *(AGE**(-0.287));

---

@chinna0369 wrote:

Hi all, 

I have below derivation, can anyone help how can I implement this in sas?

Thanks,

Adithya

---

[ballardw]

I don't see a square root anywhere much less a negative one.

In SAS you use the ** operator to exponentiate a value:

data example;
    x= 123;
   /* calculate x squared*/
    y= x**2;
    /* x to the minus 0.287 power*/
    z= x**(-0.287);
run;

[Sajid01]

Hello @chinna0369 
I would like to point that negative numbers have no real square root. 

Incidentally in solving your equation there is no need to calculate a square root.

There are many approaches to solve your equations, I would prefer the following.

I am first creating a user defined function. This function can be used like any other function.

Then I have shown an example usage.

/* Creating function*/
proc fcmp outlib=work.userfuncs.mymath;
function egfr(gender, scr,age);
term1=194*input(&scr.,best12.)**(-1.094) *input(&Age.,best12.)**(-0.287);
if(upcase("&gender") eq "MALE")then factor=1;
 else factor=0.739;;
return (factor*term1);
endsub;


/* Example usage*/
options cmplib=work.userfuncs;
data _null_;
Gender=female;
scr=100;
age=50;
egfr=egfr(gender,scr,age);
put egfr=;
run;