I am looking at a survival analysis using Cox PH models. I am interested in the effect of a continuous variable V1 on survival.
I want to look at interaction terms with my model. I believe variable V2 is also partly predictive of survival but I am not sure to what extent and if it is directly influencing V1. I was told by a supervisor to look at interactions between the two variables by creating a product variable (V1*V2) and including that in my model. I was also told that P>0.1 is considered significant due to a loss of power when creating the product term. As such I have the following output:
My interpretation is therefore. V1 is predictive of death, but V2 more so, and that V1 and V2 interact with each other.
What do I do next? V1 is the variable of interest and V2 is a biological confounder.