ARMD

These are the data of a clinical trial involving patients suffering from age-related macular degeneration (ARMD), a condition that involves a progressive loss of vision. A total of \(181\) patients from \(36\) centers participated in the trial. Patients' visual acuity was assessed using standardized vision charts. There were two treatment conditions (placebo and interferon-\(\alpha\)). The potential surrogate endpoint is the change in the visual acuity at \(24\) weeks (\(6\) months) after starting treatment. The true endpoint is the change in the visual acuity at \(52\) weeks.

In a clinical trial, it frequently occurs that the most credible outcome to evaluate the effectiveness of a new therapy (the true endpoint) is difficult to measure. In such a situation, it can be an effective strategy to replace the true endpoint by a (bio)marker that is easier to measure and that allows for a prediction of the treatment effect on the true endpoint (a surrogate endpoint). The package 'Surrogate' allows for an evaluation of the appropriateness of a candidate surrogate endpoint based on the meta-analytic, information-theoretic, and causal-inference frameworks. Part of this software has been developed using funding provided from the European Union's Seventh Framework Programme for research, technological development and demonstration under Grant Agreement no 602552.

Wim der Elst

Surrogate

Evaluation of Surrogate Endpoints in Clinical Trials

ARMD function

A <code>data.frame</code> with \(181\) observations on \(5\) variables.<dl class="dl-horizontal">
 <dt><code>Id</code></dt><dd>The Patient ID.</dd>
 <dt><code>Center</code></dt><dd>The center in which the patient was treated.</dd>
 <dt><code>Treat</code></dt><dd>The treatment indicator, coded as \(-1\) = placebo and \(1\) = interferon-\(\alpha\).</dd>
 <dt><code>Diff24</code></dt><dd>The change in the visual acuity at \(24\) weeks after starting treatment. This endpoint is a potential surrogate for <code>Diff52</code>.</dd>
 <dt><code>Diff52</code></dt><dd>The change in the visual acuity at \(52\) weeks after starting treatment. This outcome serves as the true endpoint.</dd>
 </dl>

Format

Data of the Age-Related Macular Degeneration Study — ARMD

A <code>data.frame</code> with \(181\) observations on \(5\) variables.<dl class='dl-horizontal'>
 <dt><code>Id</code></dt><dd>The Patient ID.</dd>
 <dt><code>Center</code></dt><dd>The center in which the patient was treated.</dd>
 <dt><code>Treat</code></dt><dd>The treatment indicator, coded as \(-1\) = placebo and \(1\) = interferon-\(\alpha\).</dd>
 <dt><code>Diff24</code></dt><dd>The change in the visual acuity at \(24\) weeks after starting treatment. This endpoint is a potential surrogate for <code>Diff52</code>.</dd>
 <dt><code>Diff52</code></dt><dd>The change in the visual acuity at \(52\) weeks after starting treatment. This outcome serves as the true endpoint.</dd>
 </dl>

ARMD: Data of the Age-Related Macular Degeneration Study

Description

Usage

Arguments

Format