Processing math: 100%

Exposure Adjusted Event Rate

This is a supplementary document for the file “Exposure-Adjusted Adverse Event Summary (Updated)”. We first provide an explanation for the calculation of the exposure adjusted event rate (EAER) of adverse events, and then briefly summarize the programming steps of this calculation.

EAER formula explanation

EAER formula

EAERj(EAER for Trtj)=total number of events for Trtjtotal person-days for Trtj/(exp factor)=total number of events for Trtj×exp factortotal person-days for Trtj

The exposure factor (exp factor) will be adjusted depending on the adjustment unit defined by users. For instance, when the adjustment unit is ‘100 person-month’, EAER will be computed as follows:

EAERj(100 person-months)=total number of events for Trtj×exp factor(=100×30.4367)total person-days for Trtj=total number of events for Trtj×3043.67total person-days for Trtj

EAER for different types of AEs

As an example, below are the EAER definitions for three types of AEs using three treatment groups (PBO, Low Dose, High Dose).

ANY AE adj rate

EAERPBO(100 person-months)=total number of AEs for PBO×3043.67total person-days for PBO

EAERLD(100 person-months)=total number of AEs for Low Dose×3043.67total person-days for Low Dose

EAERHD(100 person-months)=total number of AEs for High Dose×3043.67total person-days for High Dose

Serious AE adj rate

EAERPBO(100 person-months)=total number of SAEs for PBO×3043.67total person-days for PBO

EAERLD(100 person-months)=total number of SAEs for Low Dose×3043.67total person-days for Low Dose

EAERHD(100 person-months)=total number of SAEs for High Dose×3043.67total person-days for High Dose

REL AE adj rate

EAERPBO(100 person-months)=total number of Drug-Related AEs for PBO×3043.67total person-days for PBO

EAERLD(100 person-months)=total number of Drug-Related AEs for Low Dose×3043.67total person-days for Low Dose

EAERHD(100 person-months)=total number of Drug-Related AEs for High Dose×3043.67total person-days for High Dose

Programming steps of EAER

library(metalite.ae)
meta <- meta_ae_example()

x <- meta |>
  prepare_ae_summary(
    population = "apat",
    observation = "wk12",
    parameter = "any;rel;ser",
  ) |>
  extend_ae_summary_eaer(
    duration_var = "TRTDUR",
    adj_unit = "month"
  )

x
## List of 17
##  $ meta           :List of 7
##  $ population     : chr "apat"
##  $ observation    : chr "wk12"
##  $ parameter      : chr "any;rel;ser"
##  $ n              :'data.frame': 5 obs. of  4 variables:
##  $ order          : num [1:5] 1 100 200 300 400
##  $ group          : chr [1:4] "Placebo" "Low Dose" "High Dose" "Total"
##  $ reference_group: num 1
##  $ prop           :'data.frame': 5 obs. of  4 variables:
##  $ diff           :'data.frame': 5 obs. of  2 variables:
##  $ n_pop          :'data.frame': 1 obs. of  4 variables:
##  $ name           : chr [1:5] "Participants in population" "with one or more adverse events" "with no adverse events" "with drug-related{^a} adverse events" ...
##  $ prepare_call   : language prepare_ae_summary(meta = meta, population = "apat", observation = "wk12",      parameter = "any;rel;ser", )
##  $ total_exp      :'data.frame': 1 obs. of  4 variables:
##  $ event_num      :'data.frame': 3 obs. of  4 variables:
##  $ eaer           :'data.frame': 3 obs. of  4 variables:
##  $ adj_unit       : chr "month"

Run x$eaer to get the EAER:

x$eaer
##    Placebo    Low Dose   High Dose       Total
## 1 71.46214 159.1724513 165.8725416 122.9359029
## 2 31.57630 106.8467949 101.7108552  72.6674019
## 3  0.00000   0.3659137   0.7291101   0.3096622