topic Re: Working with longitudinal data. in SAS Programming

Working with longitudinal data.

PhanS — Thu, 11 Oct 2012 01:56:49 GMT

Dear Everyone,

I am delighted to engage with the SAS support communities. I found the supports, thus far, are very helpful to me with respect to my data manipulations that I am working at this moment.

For this project, I am going to finish my exercises soon, although I would like to post two challenges that I cannot answer myself. These challenges are:

1) Identifying continuity in longitudinal data.

This issue I am looking for a syntax that allows me to calculate changes over time in viral load tests that can be ranged form 1 to over 300 tests in 10 years.

2) When I calculate changes in the first year of VL, I have observed that my data was no longer in longitudinal. I observe that I have one record for each subject study.

My question here how can I keep my data to be longitudinal format.

I look forward to hearing everyone's assistance.

Phan S.

Re: Working with longitudinal data.

PhanS — Fri, 12 Oct 2012 13:33:42 GMT

Hello everyone,

I hope someone can help me with solutions for my inquires. Please let me know if you have concerns.

Thanks,

Phan S.

Re: Working with longitudinal data.

ballardw — Fri, 12 Oct 2012 17:18:05 GMT

Do you need a running cumulative change for each patient?

How do you calculate change in viral load, change in a count or a percent or some other rate?

Re: Working with longitudinal data.

PhanS — Fri, 12 Oct 2012 19:32:08 GMT

Hello,

I will use log10 as well as actual values. I do not use percentage.

Re. cumulative changes, I will look for each subject as well as for the cohort.

Thanks,

Phan S.

Re: Working with longitudinal data.

ballardw — Fri, 12 Oct 2012 22:50:38 GMT

Might be time to post some dummy input data and the desired output(s) and what you did that you didn't like.