OHDSI Home | Forums | Wiki | Github

Atlas - How to use Criteria fields

Hi People,

I am trying to play around with ATLAS and need your help.

My requirement is that I need to identify patients who have had insulin in the first 2 years from their first diagnosis.

So, I tried the below but I guess its incorrect. You can also get the cohort from public Atlas

I can understand 1 day after index start date but where can I mention that it should be within 730 days from index start date.

I tend to read the criteria that I have setup as 1 day after the index start date and 730 days before index start date. but I am confused on this part as both are contradictory.

How should I interpret them and how can I define the criteria right?

Thanks for your help

the way you phrased it is a contridiction…you can’t specify a time window starting some point in the future to some point in the past.

You want to find drug exposures between 1 day after and 730 days after index (the diagnosis of T2DM). So just change the ‘before’ to ‘after’.

Just out of curiosity: what led you to decide that you would want to make the window ‘1 day after to 730 days before’? What time window would that represent?

1 Like

Hi @Chris_Knoll,

Yes, the way I defined it was incorrect. But when I thought of using after, I had below doubt.

It could purely be due to my limitation with the English language as well.

Let’s consider below example

If we define our criteria like below
where event starts between 1 day after and 730 days after index start date, I tend to relate it with column H which is basically saying anytime after 1 day from index start date. (between 1 day after and 730 day after - indicates all day after 1st day?)

But it actually means column G and the output will only be patient 1 and 2. Am I right?

Okay, Because I wanted to capture insulin records after 1 day from index and within 730 days from index, I was trying 1 day after and 730 days before. But yes, I agree that 730 days before goes to the past (before index date), but I didn’t know how to implement it. I tried adding additional constraint but that was asking for even more information and I was lost. Again, could be due to my limitation with the language or I was finding difficult to understand/visualize how the criteria works.

No problem, @Akshay. Any feedback to clarify the language limitatons in the tool would be helpful.

The statement ‘between 1 day after and 730 days after index’ does mean column G. Between 1 day after and 730 days after means that the ‘insulin day after index’ must be between 1 and 730.

The ‘between’ part of the statement means that the value of the days to insulin must fall with the range of numbers starting with your first value (1) and your second value (730). The ‘before’ and ‘after’ part is saying how you want to add your value to the index date as ‘days before’ means subtract, and '‘days after’ means add. If you changed your range to say 'between 30 days before and 730 days after index, then if you calculated the days to insulin, any value between -30 and +730 would match column G (30 days before means the index date minus 30 days).

So, looking at your column headings, I understand some of the confusion now: saying ‘Between 1 and 730 das FROM index date’ is operating in a mode where you think of a time window (in this case 730 days) and you say where that 730 day window starts from the start date. That’s one way of thinking of it, but the way the tool works is that you specify the window as a lower bound and upper bound by specifying where the lower bound shoudl be set (1 day after) and the uper bound (730 days after).

Another question for you: in row 3,4 and 5, you calculated 1064 days to insulin from index. In column H, you say 'between 1 day after index and 730 days after index) but I’m not seeing how 1065, 1127 or 1063 days would result in a Y in that column since those values are greater than 730. Could you clarify this? I think I am missing somthing.

One last point on the ‘before - after’ syntax of defining the range: if you don’t want to specify a lower bound or an upper bound, then you can use the ‘All days’ option…if you want to say that the inslulin had to appear any time after 1 day after index, you would say ‘Between 1 day after and all days after index’. If you did it that way, then the 1065, 1127 and 1063 records would be returned because there’s no upper bound to where you are allowed to find the insulin, just as long as it is found 1 day after the index. (days to insulin must be 1 or more).

Hope this helps.

1 Like

Thanks @Chris_Knoll for your answer. I understand how it works now. But yes, since you asked for it, I am going to let you know the weird/unusual way I interpreted this. Sorry, I was totally wrong… Anyway here it is

By between 1 day after and 730 days after - I broke this into two windows (don’t know why I interpreted this way)

window 1 - Day 1 till Day 730

window 2 - Day 731 till the end of it.

So, patients 1 and 2 falls in window 1, and patients 3,4 and 5 falls in window 2. So all the patients become Y.

Hence my above question.

But yes, I do see that you have all days option as well…

btw, Is it okay if I use this thread to ask further questions related to ATLAS UI (criteria related queries)?

Should be fine. If it’s all on topic of criteria fields, then go ahead.