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From | Nick Cox <njcoxstata@gmail.com> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | Re: st: Help with multiple baseline data |
Date | Mon, 9 Sep 2013 15:33:11 +0100 |
Sounds like bysort patient (date) : gen basedate = date[1] by patient : gen elapsed = date - date[1] See also http://www.stata.com/manuals13/u.pdf p.154 Nick njcoxstata@gmail.com On 9 September 2013 15:16, Mats Martinell <matsmartinell@gmail.com> wrote: > Dear Statalist, > I'm working on a registry of patients with diabetes. The patients (cases) are included at time of diagnosis, thus almost all cases have different dates (ddmmyyyy) for their first registration. The patients are divided into three groups depending on blood sugar concentration at diagnosis. I would like to graph the mean (with 95% CI) blood sugar concentration for each group over time. My problem is the following: > > 1. Is there a way I can create a common baseline (day 0) from their date of diagnosis for each case? > > 2. The follow-up measurements are at differentdates and not at a fixed date from diagnosis. Is there a way to generate a variable for the follow-up measurements ( X days after diagnosis (day 0))? > > > Best regards, > Mats Martinell > PhD stud > Uppsala university, Sweden > > > > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/statalist-faq/ > * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/