Non-linear Regression Modelling for Medical Professionals

Overview

This repository contains supplementary materials for the manuscript, "Non-linear regression modelling for medical professionals: making curved paths straight-forward".

This repository contains R scripts for performing the analyses, and outputting the plots and tables shown in the manuscript. The following files are available:

File	Description
case_study.R	Main R script demonstrating the complete analysis workflow
simulate_data.R	Data simulation script
R_markdown_for_Supplementary_PDF.Rmd	R Markdown document for generating supplementary materials
R_markdown_for_Supplementary_PDF.pdf	Generated supplementary PDF document

Analysis Overview

The case study demonstrates:

• Data Simulation: Creating a dataset with known linear (age) and U-shaped (BMI) relationships
• Model Fitting: Using restricted cubic splines with logistic regression
• Model Evaluation: Testing for non-linearity and model diagnostics
• Visualization: Creating publication-ready plots
• Table Generation: Producing formatted tables for manuscript submission

Citation

If you use rmsMD in your work, please cite the following article:

Tingle SJ, Kourounis G, Elliot S, Harrison EM. Non-linear regression modelling for medical professionals: making curved paths straightforward. Postgrad Med J. 2025 Nov; qgaf183. DOI: 10.1093/postmj/qgaf183

BibTeX entry for reference managers:

@article{10.1093/postmj/qgaf183,
    author = {Tingle, Samuel J and Kourounis, Georgios and Elliot, Sarah and Harrison, Ewen M},
    title = {Non-linear regression modelling for medical professionals; making curved paths straightforward},
    journal = {Postgraduate Medical Journal},
    pages = {qgaf183},
    year = {2025},
    month = {11},
    issn = {0032-5473},
    doi = {10.1093/postmj/qgaf183},
    url = {https://doi.org/10.1093/postmj/qgaf183},
    eprint = {https://academic.oup.com/pmj/advance-article-pdf/doi/10.1093/postmj/qgaf183/65131196/qgaf183.pdf},
}