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Activity Number: 361 - Contributed Poster Presentations: Section on Nonparametric Statistics
Type: Contributed
Date/Time: Wednesday, August 5, 2020 : 10:00 AM to 2:00 PM
Sponsor: Section on Nonparametric Statistics
Abstract #312923
Title: Analysis of Composite Mortality and Non-Mortality Outcomes in Stepped Wedge Cluster Randomized Trials Using Simultaneous Quantile Regression
Author(s): Marzana Chowdhury* and Dylan Small and Scott D. Halpern and Katherine R. Courtright and Fan Li and Michael O. Harhay
Companies: University of Pennsylvania and University of Pennsylvania and University of Pennsylvania and University of Pennsylvania and Yale University and University of Pennsylvania
Keywords: Stepped Wedge Trial; Linear mixed effects model; Simultaneous quantile regression
Abstract:

Continuous outcomes, such as length of stay, from stepped wedge cluster randomized trials (SWCRT), are traditionally compared using linear mixed-effects models (LMM) or quantile regression (QR). For many diseases, patients die during trial follow-up. A common approach to account for death is to give patients who die a fixed value, such as the longest length of stay, or zero-free days when free-day composite outcomes are used. While this solves a conceptual problem, it engenders a spike in the continuous distribution. Motivated by an ICU-based SWCRT, we propose using simultaneous quantile regression (SQR) to compare composite outcome distributions. SQR permits (1) a joint test of treatment effects at >1 quantiles of interest, (2) inference on the whole distribution profile using bootstrap confidence intervals, and (3) comparison of treatment effects between different quantiles. We compared SQR to LMM and QR via simulations and demonstrated that SQR maintained valid type I error rates and had comparable power, suggesting its promise for analyzing spiked distributions in SWCRTs.


Authors who are presenting talks have a * after their name.

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