Comparing 2 Different Dates per Person/Member

I am trying to pull data comparing two dates per person, i.e. discharge date to the next admin date for each patient within 30 days. Also, there could be multiple discharge dates and admin dates.

Pt Name  PT Number    Admin Date       Discharge Date
-----------------------------------------------------
John Doe   55         01/02/2023       01/12/2023
John Doe   55         01/31/2023       02/05/2023
John Doe   55         05/28/2023       06/01/2023
John Doe   55         06/15/2023       06/17/2023

This patient should be counted twice because he was readmitted (01/31/2023) within 30 days of prior discharged (01/12/2023); and readmitted (06/15/2023), discharged (06/01/2023).

Great thanks!

I am expecting a field for Readmissions that output the total of readmission (30 days).

I don't know where to begin. I have created a stored procedure but that is it.

2

1 Answer

we can use table value function cross apply and some correlation to get the records which fall wtihin 30 days of eachother.

note if you have multiple dates which all fall within 30 you're count will inflate because the 1st one will include hte next 2, the next one will include the next one so you get 2 on the first admin date, and 1 on the 2nd admin date. See as an example. you didn't specify how you want this handled.

You can also switch my cross apply to an ourter apply as in my above link to see how the base dataset relates to the applied data set to get the "within 30 day" records.

Demo

Create table T1 (PtName varchar(20),  PTNumber numeric, AdminDate date,  DischargeDate date)
Insert into t1 values 
('John Doe',   55,         '01/02/2023',       '01/12/2023'),
('John Doe',   55,         '01/31/2023',       '02/05/2023'),
('John Doe',   55,         '05/28/2023',       '06/01/2023'),
('John Doe',   55,         '06/15/2023',       '06/17/2023')

Option 1) if you want the rows which are "Readmissions"

Select Z.*
FROM  T1 A
Cross Apply (Select * from T1 B
            where B.PtNumber = A.PtNumber
              and DATEADD(day, 30, A.DischargeDate) >= B.AdminDate
              and A.AdminDate < B.AdminDate) Z

Option 2) if you just want the count of readmissions by Patient

Select count(*) readmissions, Z.PTName, Z.PtNumber
FROM  T1 A
Cross Apply (Select * from T1 B
            where B.PtNumber = A.PtNumber
              and DATEADD(day, 30, A.DischargeDate) >= B.AdminDate
              and A.AdminDate < B.AdminDate) Z

Group by Z.PTName, Z.PTNumber

Gives us:

Result 1)

+----------+----------+------------+---------------+
|  PtName  | PTNumber | AdminDate  | DischargeDate |
+----------+----------+------------+---------------+
| John Doe |       55 | 2023-01-31 | 2023-02-05    |
| John Doe |       55 | 2023-06-15 | 2023-06-17    |
+----------+----------+------------+---------------+

Result 2)

+--------------+----------+----------+
| readmissions |  PTName  | PtNumber |
+--------------+----------+----------+
|            2 | John Doe |       55 |
+--------------+----------+----------+

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Sophia Al-Mansoor

Sophia Al-Mansoor

Global Business & E-Commerce Reporter

Sophia analyzes international trade, startup ecosystems, retail transformation, and supply chain logistics for modern digital publications.

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