@mwheymans profile picture
Martijn Heymans @mwheymans

Missing Data and Prediction. R packages psfmi and miceafter.

Joined January 2015
  • Tweets 130
  • Following 179
  • Followers 139
12 Photos and videos
Martijn Heymans retweeted
Am J Epidemiology@AmJEpi
10 Jul 2023
In AJE: Missing data? Don't drop observations! A longitudinal study in @hrsisr shows multiple imputation with predictive mean matching performs well, is easy to implement, and helps recover unbiased results doi.org/10.1093/aje/kwad139

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Just released on cran, psfmi package version 1.4.0 including new possibility to pool and select stratified Cox models after Multiple Imputation #rstats mwheymans.github.io/psfmi/
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Martijn Heymans retweeted
Alessandro Chiarotto@PhysioAlex
24 Mar 2023
Replying to @RoelWing
@RoelWing just published his last PhD paper in the @JPhysiother! A prognostic model for neck-related disability in patients with sub-acute neck pain was externally validated at 6 weeks with acceptable discrimination and calibration. sciencedirect.com/science/ar…
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Finding it hard to understand the Cox model and baseline hazard in R. See my post that may help you! missingdatasolutions.rbind.i… #RStats #rstudio

Prediction Modeling with the Cox model - all about the baseline hazard

This post is about different functions of the survival package, like basehaz, predict.coxph, survfit, termplot, what kind of results they provide and how they are calculated.

missingdatasolutions.rbind.io
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Martijn Heymans retweeted
Alessandro Chiarotto@PhysioAlex
18 Dec 2022
His publications are suggested reading for anyone interested in prognostic modelling for neck pain. Starting with this systematic review... pubmed.ncbi.nlm.nih.gov/2928… ...to this paper failing to externally validate the most promising models: pubmed.ncbi.nlm.nih.gov/3430… 2/3

Few promising multivariable prognostic models exist for recovery of people with non-specific neck...

PROSPERO CRD42016042204. [Wingbermühle RW, van Trijffel E, Nelissen PM, Koes B, Verhagen AP (2018) Few promising multivariable prognostic models exist for recovery of people with non-specific neck...

pubmed.ncbi.nlm.nih.gov
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Martijn Heymans retweeted
Miquel Porta@miquelporta
13 Dec 2022
A systematic review shows no performance benefit of machine learning over logistic regression for clinical prediction models jclinepi.com/article/S0895-4…

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Martijn Heymans retweeted
Journal of Clinical Epidemiology@JClinEpi
17 Oct 2022
@mwheymans
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Proud to present this paper about Handling Missing Data in Clinical Research as a Key Concept in Clinical Epidemiology @JClinEpi eur04.safelinks.protection.o…

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Martijn Heymans retweeted
Judith Bosmans@judithbosmans
26 Sep 2022
Ever wondered whether it is necessary to impute cost data before using longitudinal linear mixed-model analyses? Check out our paper below for the answer! @hannekevandonge @VroomenJanet @mwheymans doi.org/10.1007/s10198-022-0…

The handling of missing data in trial-based economic evaluations: should data be multiply imputed...

The European Journal of Health Economics - For the analysis of clinical effects, multiple imputation (MI) of missing data were shown to be unnecessary when using longitudinal linear mixed-models...

link.springer.com
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Great paper with a great team! ejnmmires.springeropen.com/a…

External validation: a simulation study to compare cross-validation versus holdout or external...

EJNMMI Research - Clinical prediction models need to be validated. In this study, we used simulation data to compare various internal and external validation approaches to validate models. Data of...

link.springer.com
Martijn Heymans retweeted
Journal of Clinical Epidemiology@JClinEpi
27 Aug 2022
#openaccess Time lags and time interactions in mixed-effects models impacted longitudinal mediation effect estimates jclinepi.com/article/S0895-4…

Time lags and time interactions in mixed effects models impacted longitudinal mediation effect...

Longitudinal mediation effects can be estimated with mixed effects models. Mixed effects models are versatile, as they accommodate the estimation of contemporaneous, lagged, time-independent, and...

jclinepi.com
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Do not dichotomize variables! Read here why, including easy to understand explanation and interpretation of linear and restricted cubic splines R code. frontiersin.org/articles/10.…
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Excited to share this NEW PAPER about pooling and selecting prognostic/prediction models after Multiple Imputation using the median of p-values rule (MPR) that outperforms more complex methods. eur04.safelinks.protection.o…
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Martijn Heymans retweeted
Posit PBC@posit_pbc
27 Jul 2022
We are excited to announce that RStudio, PBC will become Posit, PBC in October! More information here: rstudio.com/blog/rstudio-is-…

RStudio is becoming Posit

We are very excited to announce that RStudio has a new name, Posit.

posit.co
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Working with R code makes you think...should I change my name into M>artijn ?
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Martijn Heymans retweeted
Journal of Clinical Epidemiology@JClinEpi
9 May 2022
#openaccess Missing data were poorly reported and handled in randomized controlled trials with repeatedly measured continuous outcomes: a cross-sectional survey jclinepi.com/article/S0895-4…

Missing data were poorly reported and handled in randomized controlled trials with repeatedly...

Missing data are common in randomized controlled trials (RCTs) involving repeatedly measured continuous outcomes. Evidence on the reporting and handling of such outcome data is lacking, which has...

jclinepi.com
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Martijn Heymans retweeted
Wolfgang Viechtbauer@wviechtb
5 May 2022
Reminder: Tomorrow is the follow-up session to the 'Meta-Analysis with R' workshop I gave prior to #ESMARConf2022. Details here: wvbauer.com/doku.php/worksho… We will continue where I left off (see here for the materials covered so far: github.com/wviechtb/esmarcon…).
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Want to learn about the added value of splines? See: Proposed New Dynamic Prognostic Index for Diffuse Large B-Cell Lymphoma: International Metabolic Prognostic Index pubmed.ncbi.nlm.nih.gov/3535…

Proposed New Dynamic Prognostic Index for Diffuse Large B-Cell Lymphoma: International Metabolic...

A new prognostic index is proposed using MTV, age, and stage, which outperforms IPI and enables individualized estimates of patient outcome.

pubmed.ncbi.nlm.nih.gov
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Martijn Heymans retweeted
Journal of Clinical Epidemiology@JClinEpi
11 Feb 2022
Missing data was handled inconsistently in UK prediction models: a review of method used jclinepi.com/article/S0895-4…

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Martijn Heymans retweeted
Mariska Leeflang@leeflang_m
23 Nov 2021
Attending the online @APH Methodology tutorial by @JudithRijnhart: about the robustness of #multiverse analysis - assessing the effect of the researcher's degrees of freedom on the #replicability of an analysis. with @judithbosmans link.springer.com/article/10…
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