topic Re: How can I determine if midnight is included in the last day of a pateint's stay in SAS Programming

How can I determine if midnight is included in the last day of a pateint's stay

DocMartin — Mon, 05 Oct 2020 16:02:08 GMT

I have patients admitted to an intensive care unit., their start datetime (istart) and their discharge datetime (istop). I need to know if the patient's last day in the intensive care unit crossed midnight. Below are some samples datetimes. Any ideas?

istart	istop	Cross_Midnight
01/01/2020 13:00:00	01/03/2020 1:00:00	Y
01/01/2020 13:00:00	01/03/2020 23:00:00	N
01/01/2020 1:00:00	01/01/2020 23:50:00	N
01/01/2020 1:00:00	01/02/2020 2:00	Y

Thanks!

Andrew

Re: How can I determine if midnight is included in the last day of a pateint's stay

PaigeMiller — Mon, 05 Oct 2020 16:11:08 GMT

How does one determine "the patient's last day in the intensive care unit crossed midnight"? I am not clear on this. However:

Something like this?

cross_midnight = intck('dtday',istart,istop,'d')>0;

Shouldn't row 2 have cross_midnight=Y ??

By the way, it is really helpful if you provide your example data as SAS DATA step code, and not as a screen capture, so we can actually test our sample code on your actual data. Please do that from now on.

Re: How can I determine if midnight is included in the last day of a pateint's stay

Kurt_Bremser — Mon, 05 Oct 2020 16:10:23 GMT

if intck('dtday',istart,istop) > 0

if datepart(istop) > datepart(istart)

Re: How can I determine if midnight is included in the last day of a pateint's stay

DocMartin — Mon, 05 Oct 2020 16:26:14 GMT

I didn't explain it clearly. What I didn't put in my post was the length of stay: 1.500 for the first patient above, then 2.500, 0.951, and 1.042. What I wanted to do is to see if the fractional part of the length of stay crossed midnight. Did the 0.500 part of a day include midnight, .0.500, 0.951, 0.042.?

Re: How can I determine if midnight is included in the last day of a pateint's stay

PaigeMiller — Mon, 05 Oct 2020 16:36:01 GMT

@DocMartin wrote:
I didn't explain it clearly. What I didn't put in my post was the length of stay: 1.500 for the first patient above, then 2.500, 0.951, and 1.042. What I wanted to do is to see if the fractional part of the length of stay crossed midnight. Did the 0.500 part of a day include midnight, .0.500, 0.951, 0.042.?

How can a fractional part include midnight? Do you mean the istop time compared to the difference (istop time minus the fractional part) includes midnight?

Re: How can I determine if midnight is included in the last day of a pateint's stay

DocMartin — Mon, 05 Oct 2020 16:50:20 GMT

Here's the SAS code:

data icu; input istart datetime16. istop datetime16.;
cards;
01Jan20:13:00:00    03Jan20:01:00:00	 
01Jan20:13:00:00	03Jan20:23:00:00	 	
01Jan20:01:00:00	01Jan20:23:50:00	
01Jan20:01:00:00	02Jan20:02:00 
;

data icu1; set icu;
  format istart istop datetime16.;
  iculos = (istop - istart)/86400;
  put istart istop iculos;
run;

01JAN20:13:00:00 03JAN20:01:00:00 1.5
01JAN20:13:00:00 03JAN20:23:00:00 2.4166666667
01JAN20:01:00:00 01JAN20:23:05:00 0.9201388889
01JAN20:01:00:00 02JAN20:02:00:00 1.0416666667

Re: How can I determine if midnight is included in the last day of a pateint's stay

DocMartin — Mon, 05 Oct 2020 17:26:47 GMT

Yikes, I figured it out for myself. I was making things too hard. All I had to do was:
if timepart(istart) > timepart(istop) then midnight = 'Y'; else midnight = 'N';

Re: How can I determine if midnight is included in the last day of a pateint's stay

PaigeMiller — Mon, 05 Oct 2020 17:31:55 GMT

But this doesn't work if the stay in the ICU is greater than 24 hours (or does it)? How would this work on your row 2?