Marginal structural models for estimating principal stratum direct effects under the monotonicity assumption.
In epidemiological and clinical research, investigators are frequently interested in estimating the direct effect of a treatment on an outcome that is not relayed by intermediate variables. In 2009, VanderWeele presented marginal structural models (MSMs) for estimating direct effects based on interventions on the mediator. This paper focuses on direct effects based on principal stratification, i.e. principal stratum direct effects (PSDEs), which are causal effects within latent subgroups of subjects where the mediator is constant, regardless of the exposure status. We propose MSMs for estimating PSDEs. We demonstrate that the PSDE can be estimated readily using MSMs under the monotonicity assumption.
Division of Biostatistics, Clinical Research Center, Kinki University School of Medicine 377-2, Ohno-higashi, Osakasayama, Osaka 589-8511, Japan. chibay@med.kindai.ac.jp
Yasutaka
Y
Chiba
D001699:Biometry / Q000379:methods*; D002986:Clinical Trials as Topic / Q000379:methods*; D003327:Coronary Disease / Q000401:mortality / Q000628:therapy; D057194:Intention to Treat Analysis; D015233:Models, Statistical; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D016896:Treatment Outcome