Dear All,
I am modelling time to onset of a particular disease with three
covariates x1, x2, x3 and the interaction x1*x3 using Survival
Analysis. All the covariates except x1 was significant during
univariate analysis but was kept in the model due to its importance
based on other research. In the final model: HR =
exp(b1x1+b2x2+b3x3+b4x1*x3) only x1 was not significant where HR is
hazard ratio. Any suggestions on where to go from here? Since x1*x3 is
significant and x1 was not, How does one handle such a situation?
Raphael
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