Online Program

Saturday, February 20
PS3 Poster Session 3 & Continental Breakfast sponsored by Capital One Sat, Feb 20, 8:00 AM - 9:15 AM
Ballroom Foyer

Power and Sample Size Calculations for Interval-Censored Survival Analysis (303235)

Hae-Young Kim, New York Medical College 
Hung-Mo Lin, Ichan School of Medicine at Mount Sinai 
*John Michael Williamson, U.S. Centers for Disease Control and Prevention 

Keywords: Interval-censored data, power, sample size, survival analysis

We propose a method for calculating power and sample size for studies involving interval-censored failure time data that only involves standard software required for fitting the appropriate parametric survival model. We use the framework of a longitudinal study where patients are assessed periodically for a response and the only resultant information available to the investigators is the failure window: the time between the last negative and first positive test results. The survival model is fit to an expanded data set using easily computed weights. We illustrate with a Weibull survival model and a two-group comparison, although the method is easily extended to a variety of survival and censoring distributions. The investigator can specify a group difference in terms of a hazards ratio. Our simulation results demonstrate the merits of these proposed power calculations. We also explore how the number of assessments (visits), and thus the corresponding lengths of the failure intervals, affect study power. The proposed method can be easily extended to more complex study designs.