Sample size calculation for the Andersen-Gill model comparing rates of recurrent events

TL;DR

This paper develops a method to calculate the required sample size and power for the Andersen-Gill model in recurrent event analysis, aiding clinical trial design with variable event rates.

Contribution

It introduces a new procedure for sample size calculation for the Wald test in the Andersen-Gill model, applicable to various trial types.

Findings

Procedure demonstrated through numerical examples

Sample SAS code provided for implementation

Applicable to superiority, noninferiority, and equivalence trials

Abstract

Recurrent events arise frequently in biomedical research, where the subject may experience the same type of events more than once. The Andersen-Gill (AG) model has become increasingly popular in the analysis of recurrent events particularly when the event rate is not constant over time. We propose a procedure for calculating the power and sample size for the robust Wald test from the AG model in superiority, noninferiority, and equivalence clinical trials. Its performance is demonstrated by numerical examples. Sample SAS code is provided in the Supplementary Material.