Flexible parametric survival analysis with frailty, take two

Hi everyone, Today we are going to continue learning about flexible parametric survival models with random effects, as a follow-up to a previous post on our blog. Specifically, we are going to replicate the analysis from that post, but with a twist: today, we are going to use the {merlin} package in R. {merlin} in R isContinue reading “Flexible parametric survival analysis with frailty, take two”

Biostatistics & Epidemiology Summer School returns!

I’m delighted to say that the Summer School on Modern Methods in Biostatistics and Epidemiology is returning to the picturesque CastelBrando with a huge range of courses in June 2023! Join me in Treviso, Italy, where I will be back teaching our week long (half days) course on Joint modelling of longitudinal and survival data,Continue reading “Biostatistics & Epidemiology Summer School returns!”

stmt: Modelling multiple timescales using flexible parametric survival models in Stata

After many years of working on the stmt package in Stata, our paper Flexible parametric survival analysis with multiple timescales: Estimation and implementation using stmt was recently published in the Stata Journal (1). stmt can be installed by typing in Stata: The aim of this paper was to describe and illustrate how to model multipleContinue reading “stmt: Modelling multiple timescales using flexible parametric survival models in Stata”

Multivariate joint longitudinal-survival models

Joint longitudinal-survival models have been widely developed, but there are many avenues of research where they are lacking in terms of methodological development, and importantly, accessible implementations. We think merlin fills a few gaps. In this post, we’ll take a look at the extension to modelling multiple continuous longitudinal outcomes, jointly with survival. For simplicity,Continue reading “Multivariate joint longitudinal-survival models”

Joint longitudinal-survival models with time-dependent effects (non-proportional hazards)

In this post we’ll focus on how to model time-dependent effects (non-proportional hazards), specifically within a joint longitudinal-survival model. If this is your first time reading a little about joint models, check out our other posts on joint models on our Tutorials page. Now joint models are becoming commonplace in medical research, but as always,Continue reading “Joint longitudinal-survival models with time-dependent effects (non-proportional hazards)”

Relative survival analysis

Relative survival models are predominantly used in population based cancer epidemiology (Dickman et al. 2004), where interest lies in modelling and quantifying the excess mortality in a population with a particular disease, compared to a reference population, appropriately matched on things like age, gender and calendar time. One of the benefits of the approach isContinue reading “Relative survival analysis”

Flexible parametric survival analysis with frailty

This example takes a look at incorporating a frailty, or random intercept, into a flexible parametric survival model, and how to fit them in Stata. First we’ll use merlin to estimate our model, and then the more user-friendly wrapper function stmixed. More details on these models can be found in the following papers: Crowther MJ,Continue reading “Flexible parametric survival analysis with frailty”

Simulation, modelling and prediction with a non-linear covariate effect in survival analysis

Let’s begin. There will be a single continuous covariate, representing age, with a non-linear effect influencing survival. We’ll simulate survival times under a data-generating model that incorporates a non-linear effect of age. We’ll then fit some models accounting for the non-linear effect of age, and finally make predictions for specified values of age. Sounds simple,Continue reading “Simulation, modelling and prediction with a non-linear covariate effect in survival analysis”