topic Re: Area under the curve glucose in New SAS User

Area under the curve glucose

Soontobeprofess — Fri, 23 Jul 2021 23:24:24 GMT

I am a graduate student and I need to analyze area under the curve for the following data set (individual subject), can someone give me a simple code for it please. I will do this for every subject and after that I will run the ANOVAs pre and post, thank you very much.

Min Glucose

-7	75
0	73
2	73
12	78
28	106
43	110
58	102
73	101
88	99
103	88
118	82
133	82
148	80
163	79
178	76
193	74
209	75
224	74
244	78

Re: Area under the curve glucose

Ksharp — Sat, 24 Jul 2021 10:32:00 GMT

data have;
input Min    Glucose ;
cards;
-7	75
0	73
2	73
12	78
28	106
43	110
58	102
73	101
88	99
103	88
118	82
133	82
148	80
163	79
178	76
193	74
209	75
224	74
244	78
;

data temp;
 set have;
 delta=dif(min);
 high=mean(lag(Glucose),Glucose);
run;
proc sql noprint;
select sum(delta*high) into : auc from temp;
quit;


proc sgplot data=have;
series x=min y=glucose;
inset "AUC=&auc";
run;

Re: Area under the curve glucose

Soontobeprofess — Sat, 24 Jul 2021 14:22:51 GMT

Dear community

Thank you so much for your help. The code runs fine. I have two more questions:

The first, I forgot to ask, I need to calculate AUC from minute 0 to 240 only.

The second one, in case on missing data (in rare cases, some of the glucose sensors didn't catch the last hour of glucose readings), how can i modify the code to compensate for it? Thank you very much.

Re: Area under the curve glucose

Ksharp — Sun, 25 Jul 2021 10:49:18 GMT

For first question:
Add a filter condition .

data temp;
set have(where=(min between 0 and 240));
..........

For second question, you can impute the missing value with lag value . Like :
data temp;
set have(where=(min between 0 and 240));
retain new_glucose ;
if not missing(glucose ) then new_glucose =glucose ;
drop glucose ;
run;

-7	75
0	73
2	73
12	78
28	106
43	110
58	102
73	101
88	99
103	88
118	82
133	82
148	80
163	79
178	76
193	74
209	75
224	74
244	78

-7	75
0	73
2	73
12	78
28	106
43	110
58	102
73	101
88	99
103	88
118	82
133	82
148	80
163	79
178	76
193	74
209	75
224	74
244	78

-7	75
0	73
2	73
12	78
28	106
43	110
58	102
73	101
88	99
103	88
118	82
133	82
148	80
163	79
178	76
193	74
209	75
224	74
244	78