Automated biomarker analysis

The goals of the aba package are the following:

• to facilitate sound statistical modelling in clinical research
• to provide advanced tools for biomarker-based planning of clinical trials
• to generate publication-ready tables and figures

With the aba package, it becomes easier to fit statistical models on permuatations of covariates / predictors / outcomes / groups, to make it easier to investigate how biomarkers can be used to plan (screening / enirichment) and analyze clinical trials, and to facilitate multi-cohort validation studies when data cannot be easily shared between collaborators.

Getting started

To view tutorials and examples of how to use the package, you can visit the package website at https://ncullen93.github.io/abaR/.

You can install the development version of the aba package from GitHub with the following:

# install.packages("devtools")
devtools::install_github("ncullen93/abaR")

The general workflow of fitting an aba model for statistical analysis looks like this:

library(aba)

df <- aba::adnimerge %>% filter(VISCODE == 'bl')

model_spec <- df %>% aba_model() %>%
  set_groups(everyone()) %>%
  set_outcomes(ConvertedToAlzheimers, CSF_ABETA_STATUS_bl) %>%
  set_predictors(
    PLASMA_ABETA_bl,
    PLASMA_PTAU181_bl,
    PLASMA_NFL_bl,
    c(PLASMA_ABETA_bl, PLASMA_PTAU181_bl, PLASMA_NFL_bl)
  ) %>%
  set_stats(
    stat_glm(std.beta=T)
  )

model_fit <- model_spec %>% fit()
model_summary <- model_fit %>% summary()

Publications

Some publications whose analysis has been done partially or completely with functions from the aba package are featured here:

• Individualized prognosis of cognitive decline and dementia in mild cognitive impairment based on plasma biomarker combinations NC Cullen, A Leuzy, S Palmqvist, S Janelidze, E Stomrud, P Pesini, et al. Nature Aging, 2021

• Prediction of future Alzheimer’s disease dementia using plasma phospho-tau combined with other accessible measures S Palmqvist, P Tideman, N Cullen, H Zetterberg, K Blennow, JL Dage, et al. Nature Medicine, 2021

• Plasma biomarkers of Alzheimer’s disease improve prediction of cognitive decline in cognitively unimpaired elderly populations NC Cullen, A Leuzy, S Janelidze, S Palmqvist, AL Svenningsson, et al. Nature Communications, 2021

• Comparing progression biomarkers in clinical trials of early Alzheimer’s disease NC Cullen, H Zetterberg, PS Insel, B Olsson, U Andreasson, et al. Annals of Clinical and Translational Neurology 7 (9), 1661-1673

Cite

If you use the aba package in your work, we appreciate if you cite us. An example statement which can be added at the end of the “Statistical analysis” section of your methods is provided here:

The analysis was done in the R programming language (v4.0.3) using the Automated Biomarker Analysis for R (“aba”) package [citation].

Receiving help

The easiest way to get help is to create an issue on the github page or to send us an email with your questions.