# Visualization of HCE using maraca plots

#### Samvel B. Gasparyan

## Visualization

### Setup

Load the package `hce` and check the version:

    library(hce)
    packageVersion("hce")
    #> [1] '0.8.8'

For citing the package, run `citation("hce")` (Gasparyan 2025).

### The Maraca Plot

The maraca plot (named for its visual similarity to the musical instrument) has been recently introduced (Karpefors, Lindholm, and Gasparyan 2023) for the visualization of HCEs, which combine multiple dichotomous outcomes with a single continuous endpoint. The maraca plot visualizes the contribution of components of a hierarchical composite endpoint (HCE) over time. It is formed by adjoining, from left to right, uniformly scaled Kaplan–Meier plots of times to each dichotomous outcome among those without more severe outcomes, with a superimposed box/violin plot of the continuous outcome.

The maraca plot is implemented in the `maraca` package (Martin Karpefors, Samvel B. Gasparyan, and Monika Huhn 2024), which depends on the `hce` package. The `maraca` package includes a `plot.hce()` method to visualize objects of type `hce`. Consider the following example:

    library(maraca)
    Rates_A <- 10
    Rates_P <- 15
    dat <- simHCE(n = 1000, n0 = 500, TTE_A = Rates_A, TTE_P = Rates_P,
                  CM_A = 0.2, CM_P = 0, seed = 2, shape = 0.35)
    plot(dat)

The example illustrates a maraca plot with a single dishotomous outcome combined with a continuous outcome. The dischotmous outcomes over time are simulated from a Weibull distribution with `shape = 0.35` in both treatment groups. The `rate` parameter in the active group is 10 per 100 patients per year, and 15 in the control group (100 patients per year is the default value).

## References

Gasparyan, Samvel B. 2025. hce: Design and Analysis of Hierarchical Composite Endpoints. CRAN: The Comprehensive R Archive Network, R Package, Version 0.8.8. https://doi.org/10.32614/CRAN.package.hce.
Karpefors, Martin, Daniel Lindholm, and Samvel B Gasparyan. 2023. “The Maraca Plot: A Novel Visualization of Hierarchical Composite Endpoints.” Clinical Trials 20 (1): 84–88. https://doi.org/10.1177/17407745221134949.
Martin Karpefors, Samvel B. Gasparyan, and Monika Huhn. 2024. Maraca: The Maraca Plot: Visualization of Hierarchical Composite Endpoints in Clinical Trials. https://CRAN.R-project.org/package=maraca.