Repeated measures correlation analysis

[doctortimi]

I am trying to conduct a correlation analysis on repeated measures and I'll appreciate some help. I know a regular proc corr will not answer this question because measures are not independent and also a few patients have missing data. Here's an example code showing the dataset I have: 

data have;
input PID time X Y;
datalines;
001 1 4 4.3
001 2 2.5 3.9
001 3 6 .
002 1 0.3 2
002 2 7 2.1
;
run;

Thanks!

[Rick_SAS]

There are many correlations... on average? For each patient? Take a look at the paper

"Estimation of correlation coefficient in data with repeated measures", which describes several measures and how to compute them in SAS.