Comparing cross-sectional stepped-wedge and cluster randomized trials with time-to-event endpoints

Oregon Convention Center 

Stepped wedge cluster randomized trials (SW-CRTs) are a form of trial whereby clusters are progressively transitioned from control to intervention, and the timing of transition is randomized for each cluster. SW-CRTs can be attractive when it is difficult to simultaneously implement the intervention in an adequate number of clusters to facilitate a parallel design; however, they pose their own logistical and analytic challenges that may make a traditional cluster randomized trial (CRT) a more feasible option. It is not always clear which design is better suited. In addition, SW-CRTs with continuous or binary endpoints often have larger power compared to parallel CRTs; it is unclear whether this observation holds with time-to-event endpoints, where pragmatic trial interest is growing. In this talk, we will compare the operating characteristics of cross-sectional parallel CRTs and SW-CRTs with time-to-event endpoints, testing either cluster- or individual-level interventions. We will also explore two paradigms of cross-sectionality for SW-CRTs: events that may be observed beyond the period of study entry, and events that are administratively censored at the end of a period.

pragmatic trial

intracluster correlation

trial design

design choice

clustering 

Biometrics Section