Prepare a dataframe for creating AE plots
df_builder_ae(df_pat_grp, df_pat_llt, ref_grp = NULL)A data frame of patient groups. Must contain columns USUBJID (patient ID)
and RDGRPNAME (group assignment).
A data frame with USUBJID (subject ID), EINUM (AE ID), EILLTN (LLT identifier), EIPTN (PT identifier), EISOCPN (soc identifier) and EIGRDM (severity grade)
(Optional) A reference group for comparisons. Defaults to the first group in df_pat_grp.
A dataframe with all the info to build AE plots