5 papers
Performance of prior event rate ratio method in the presence of differential mortality or dropout
Yin Bun Cheung, Xiangmei Ma
Purpose: Prior event rate ratio (PERR) method was proposed to control for measured or unmeasured confounders in real-world evaluation of effectiveness and safety of medical treatme…
Bias reduction method for prior event rate ratio, with application to emergency department visit rates in patients with advanced cancer
Xiangmei Ma, Chetna Malhotra, Eric Andrew Finkelstein +1
Objectives: Prior event rate ratio (PERR) is a promising approach to control confounding in observational and real-world evidence research. One of its assumptions is that occurrenc…
Reverse time-to-death as time-scale in time-to-event analysis for studies of advanced illness and palliative care
Yin Bun Cheung, Xiangmei Ma, Isha Chaudhry +5
Background: Incidence of adverse outcome events rises as patients with advanced illness approach end-of-life. Exposures that tend to occur near end-of-life, e.g., use of wheelchair…
Strategy to control biases in prior event rate ratio method, with application to palliative care in patients with advanced cancer
Xiangmei Ma, Grace Meijuan Yang, Qingyuan Zhuang +1
Objectives: Prior event rate ratio (PERR) is a method shown to perform well in mitigating confounding in real-world evidence research but it depends on several model assumptions. W…
Robust evaluation of vaccine effects based on estimation of vaccine efficacy curve
Ziwei Zhao, Xiangmei Ma, Paul Milligan +1
Background: The Cox model and its extensions assuming proportional hazards is widely used to estimate vaccine efficacy (VE). In the typical situation that VE wanes over time, the V…