stan-dev / stan-dev/rstanarm

stan_jm joint model with non-linear association between biomarker value and hazard

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R
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Description

Summary:

Can non-linear functions of the biomarker value / slope be specified?
For example if a biomarker was associated with an increased hazard at high or low values

Reproducible Steps:

If logbili increased the hazard of death if it was very low or very high, how might one alter the code below to allow for this?

mod1 <- stan_jm(formulaLong = logBili ~ sex + trt + year + (year | id), 
                dataLong = pbcLong,
                formulaEvent = survival::Surv(futimeYears, death) ~ sex + trt, 
                dataEvent = pbcSurv,
                time_var = "year",
                chains = 1, refresh = 2000, seed = 12345)
RStanARM Version:

2.21.1

R Version:

4.0.2

Many thanks

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First steps

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Research direction

Start at the stan_jm entry point, focusing on how formulaEvent represents associations between longitudinal biomarkers and event hazards. Determine how users could specify nonlinear effects of biomarker value or slope, then verify that the example can represent increased hazard at both very low and very high logBili values.

Written by the indexing model from the issue text.

Assessment

Tech stack
r
Domain
data
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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