topic Re: Continuous enrollment gap by multiple categories in SAS Programming

Continuous enrollment gap by multiple categories

A_Swoosh — Tue, 28 Jul 2020 16:37:10 GMT

Hi all,

I've seen other threads in the SAS programming community that address the issue of continuous enrollment with various lags. I wanted to present a more complex request involving additional variables aside from date.

I have a subset example of a sample dataset as follows:

data History;
input patid plan lob $ aid $ eligible start end;
informat start end mmddyy10.;
format start end date9.;
cards;
1 1 MC LIS 1 10/1/2019 12/31/9999
1 2 MC LIS 1 9/1/2019 9/30/2019
1 1 MC LIS 1 10/1/2018 08/31/2019
1 . FFS LIS 1 4/1/2018 12/31/9999
1 1 MC LIS 1 4/1/2018 9/30/2018
1 . FFS noLIS 0 8/1/2015 3/31/2018
1 1 MC noLIS 0 8/1/2015 3/31/2018
2 . FFS LIS 1 12/18/2019 12/31/9999
2 3 MC LIS 1 6/1/2019 12/17/2019
2 . FFS LIS 1 5/1/2019 12/31/9999
2 3 MC LIS 1 8/1/2018 4/30/2019
2 3 MC LIS 1 7/1/2018 7/31/2018
2 . FFS LIS 1 5/1/2018 4/30/2019
3 2 MC noLIS 0 8/1/2018 12/31/9999
3 2 MC noLIS 0 8/1/2017 7/31/2018
3 . FFS noLIS 0 5/1/2017 12/31/9999
3 . FFS noLIS 0 12/1/2012 4/30/2017
3 2 MC noLIS 0 12/1/2012 4/30/2017
;
run;

This dataset has:
1) patient id
2) Plan
3) Line of Business (e.g. Medicare FFS or Managed Care (MC)
4) Aid (LIS vs. noLIS)
5) Eligibility Criteria
6) Start Date
7) End Date

Want:

I want to create 2 datasets; continuously enrolled for the calendar year with no more than 1 gap of 45 days

By aid (LIS)--like a case vs control with the aid category being the identifier

Results:
Patient 1: Would fall into the case group; has only 1 gap of 30 days so it is included
Patient 2: Would be removed since they have 2 gaps in enrollment
Patient 3: Would fall into the control group; no gap and has noLIS

Re: Continuous enrollment gap by multiple categories

mkeintz — Tue, 28 Jul 2020 05:23:09 GMT

What does 12/31/9999 mean? Does start=01APR2018 with end=31DEC999 mean that time span overlaps with all date ranges after 01APR2018? This would mean there can no gaps in that range.
Which brings me to this question. What is a gap? The only way I can see the 30 day gap for PATID 1 that you mention is if I limit the consideration to records with PLAN=1.

But if I apply the same rule to PATID 2 (looking for gaps with a given PLAN for PATID 2) I don't see the multiple 45 day gaps you cite.
Which in turn makes me ask whether you intend to ignore records with PLAN=.

Re: Continuous enrollment gap by multiple categories

A_Swoosh — Wed, 29 Jul 2020 23:06:31 GMT

@mkeintz

1. 9999 end date means it’s current and basically has no gaps. It extends beyond the measurement year.

2. A gap is continuously enrolled for the entire calendar year with no more than 1 gap of 45 days.

Edit: I corrected the instance for patient 2. They have 2 gaps; one from May to June and another from 12/17-12/31

3. Plan is only needed for this instance; The plan they begin the measurement year with (2019). Any breaks of more than 45 days (eg row 2 for patient 1) would be considered a gap. So for patient 1, they would be in the case group because their aid is LIS, they are eligible and they have 1 gap (row 2 equaling less than 45 days).

Re: Continuous enrollment gap by multiple categories

A_Swoosh — Wed, 29 Jul 2020 23:05:58 GMT

I'm not sure if I'm on the right track but this is what I have so far:

%let mstart  = 01JAN;
%let mend    = 31DEC;
%let ystart  = 2019;
%let yend    = 2019;

proc sort data = history out = cases (keep = patid LOB aid PLAN StartDate EndDate eligible);
			by patid StartDate EndDate;
			where EndDate > "&mstart.&ystart."d and StartDate < "&mend.&yend."d and LOB = "MC" and (intnx('year',DOB,18,'same')) > "&mstart.&ystart."d and eligible=1
run;

		data cases_test;
			retain gap_count last_start service_end service_began official_start official_end;
			set cases;
			by patid;
			format last_start service_end service_began official_start official_end date9.;


			if first.patidthen do;
				if StartDate >= "&mstart.&ystart."d then service_began = StartDate;
				else service_began = "&mstart.&ystart."d;
				if EndDate <= "&mend.&yend."d then service_end = EndDate;
				else service_end = "&mend.&yend."d;
				if StartDate >= "&mstart.&ystart."d then last_start=StartDate;
				else last_start = "&mstart.&ystart."d;
				gap_count=0;
			end;
			else do;
				if StartDate < service_began then do;
					if StartDate >= "&mstart.&ystart."d then service_began = StartDate;
					else service_began = "&mstart.&ystart."d;
				end;
				else service_began = service_began;
				if EndDate > service_end then do;
					if EndDate <= "&mend.&yend."d then service_end = EndDate;
					else service_end = "&mend.&yend."d;
				end;
				else service_end=service_end;
				if intck('day',EndDate,last_start) > 0 then gap_count=gap_count+(intck('day',EndDate,last_start)-1); 
				else gap_count=gap_count;
				if StartDate >= "&mstart.&ystart."d then last_start=StartDate;
				else last_start = "&mstart.&ystart."d;
			end;

			official_start="&mstart.&ystart."d;
			official_end="&mend.&yend."d;
run;

I think from here I may be able to use a lag from the previous row then create gap variables to count the different gaps. Not sure if there is a better approach...