Estimation of the Effect of Dynamic Treatment Regimes Under Flexible Dynamic Visit Regimes

• Activity Number: 89
• Type: Invited
• Date/Time: Monday, July 30, 2007 : 8:30 AM to 10:20 AM
• Sponsor: IMS
• Author(s): Andrea Rotnitzky*+ and Liliana Orellana
• Companies: Universidad Torcuato Di Tella and Universidad de Buenos Aire
• Keywords: Marginal Structural Model ; Causal Inference ; Dynamic Regime

Abstract

Often in the management of chronic diseases, doctors indicate the patient when the next clinic visit should be according to medical guidelines. Patients return to the clinic earlier if they need to do so. At every clinic visit treatment decisions are made. It is thus of interest to estimate the effect of dynamic treatment regimes that are to be implemented in settings in which: i) medical guidelines are used to indicate when the next clinic visit should be and these may depend on the patient health status, ii) patients may return earlier than the indicate date and iii) treatment decisions are made at each clinic visit. In this talk we present a method, based on an extension of the Marginal Structural Model (Robins 1999, 2000), which allows estimation from observational data of the effects of dynamic treatment regimes that are to be implemented in settings in which i) ii) and iii) hold.