Dear other statalist users

I've done incremental area under the curve (iAUC) calculations for glucose, c-peptide, glucagon and insulin during an oral glucose tolerance test (for both placebo and treatment). I have measurements at t=-60,0,20,40,60,90,120,180 and 240 minutes and treatment or placebo is given at -60, hence the baseline for the iAUC calculations are t=-60 min.

I followed the very helpful instructions in this thread: https://www.statalist.org/forums/for...nder-the-curve

There it was suggested to use the stata's default -integ command (cubic spline approximation) without the -trapezoidal option, since glucose and hormone curves are smooth during an oral glucose tolerance test. However, i see that many researchers within my field still use the trapezoidal method for iAUC calculation.

I was wondering whether some of you could help me deciding whether to continue with the cubic spline approximation or to stick with the "old" trapezoidal method. Specifically it would be helpful with studies comparing the trapezoidal method with the cubic spline approximation.

Best regards,
Esben