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Maya Petersen

2006

Epidemiology

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Full-Text Articles in Medicine and Health Sciences

Assessing The Effectiveness Of Antiretroviral Adherence Interventions: Using Marginal Structural Models To Replicate The Findings Of Randomized Controlled Trials., Maya L. Petersen, Yue Wang, Mark J. Van Der Laan, David R. Bangsberg Nov 2006

Assessing The Effectiveness Of Antiretroviral Adherence Interventions: Using Marginal Structural Models To Replicate The Findings Of Randomized Controlled Trials., Maya L. Petersen, Yue Wang, Mark J. Van Der Laan, David R. Bangsberg

Maya Petersen

Randomized controlled trials of interventions to improve adherence to antiretroviral medications are not always feasible. Marginal Structural Models (MSM) are a statistical methodology that aims to replicate the findings of randomized controlled trials using observational data. Under the assumption of no unmeasured confounders, three MSM estimators are available to estimate the causal effect of an intervention. Two of these estimators, G-computation and Inverse Probability of Treatment Weighted, can be implemented using standard software. G-computation relies on fitting a multivariable regression of adherence on the intervention and confounders. Thus, it is related to the standard multivariable regression approach to estimating causal …


Estimation Of Direct Causal Effects., Maya L. Petersen, Sandra E. Sinisi, Mark J. Van Der Laan May 2006

Estimation Of Direct Causal Effects., Maya L. Petersen, Sandra E. Sinisi, Mark J. Van Der Laan

Maya Petersen

Many common problems in epidemiologic and clinical research involve estimating the effect of an exposure on an outcome while blocking the exposure's effect on an intermediate variable. Effects of this kind are termed direct effects. Estimation of direct effects arises frequently in research aimed at understanding mechanistic pathways by which an exposure acts to cause or prevent disease, as well as in many other settings. Although multivariable regression is commonly used to estimate direct effects, this approach requires assumptions beyond those required for the estimation of total causal effects. In addition, when the exposure and intermediate interact to cause disease, …