On 1 Apr 2003 12:05:50 -0800, [EMAIL PROTECTED] (Scheltema, Karen) wrote: > I am struggling with how to analyze the following design. > > Morphine is known to cause urinary retention, which can result in > increased discomfort, LOS, $$, etc. I have an experimental protocol > covering three types of surgeries in which patients are randomly > assigned to treatment as usual or an additional drug to counteract the > side effects of morphine. There are two outcome variables, urinary > retention (yes/no) and pain level (0-10). Urinary retention is > measured every 8 hours and pain level is measured every 4 hours. The > catch is that not everyone is on morphine for the same length of time. > In addition 24 hours of additional data is collected after the > morphine is discontinued because the side effects of morphine hang > around that long. How do I account for some people being on morphine > for 24 hours (a total of 6 measures of urinary retention), and others > for 48 hours (a total of 9 measures of urinary retention)?
"How to account for ..." 24 or 48 hours, is one way to put it. Or, could I ask, Is there any reason that you absolutely are required to combine the two sets of data? - I'm not sure that you *can* combine them for direct statistical analysis, without a great deal of discussion. What sort of discussion can you generate while keeping them separate? You did not mention what nasty confounding exists. For instance, I bet that these folks were not *randomly* assigned to 24 vs. 48 hours of morphine, long before they ever went into surgery, but it 'happened.' Was the longer treatment inspired by pain? but somewhat discouraged by side effects, say, like urinary retention? I hope this bit of meandering might have helped... -- Rich Ulrich, [EMAIL PROTECTED] http://www.pitt.edu/~wpilib/index.html . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
