Hi Tim, Phil,
sorry it's taken so long to get back in touch.  Having now looked through
your Minitab file, I think I slightly misunderstood the nature of the
problem initially.  I suggested a Friedman test to simultaneously check
for significant differences in treatment results between your different
time "windows" and your two groups; however, a Friedman test should only
be used if your two groups are realted in some way.  Considering each
of sCr and CrC, this is what I would do:
1) To check for differences in renal function through time, compare