I am running cox PH survival analyses for diabetes as an outcome, with <10 variables and no interaction terms. The c stats are all consistent with the literature sitting at around 0.75-0.80, as expected. However, I am struggling to print calibration curves, as although the per decile points appear to be in essentially a diagonal line, the scale of the axes aren’t correct as the x=y is almost completely vertical. Here is the code that I have used: