@article{3184408,
    title = "Emulating a trial of joint dynamic strategies: An application to
monitoring and treatment of HIV-positive individuals",
    author = "Caniglia, Ellen C. and Robins, James M. and Cain, Lauren E. and Sabin, and Caroline and Logan, Roger and Abgrall, Sophie and Mugavero, Michael J. and and Hernandez-Diaz, Sonia and Meyer, Laurence and Seng, Remonie and and Drozd, Daniel R. and Seage, III, George R. and Bonnet, Fabrice and Le and Marec, Fabien and Moore, Richard D. and Reiss, Peter and van Sighem, Ard and and Mathews, William C. and Jarrin, Inma and Alejos, Belen and Deeks, and Steven G. and Muga, Roberto and Boswell, Stephen L. and Ferrer, Elena and and Eron, Joseph J. and Gill, John and Pacheco, Antonio and Grinsztejn, and Beatriz and Napravnik, Sonia and Jose, Sophie and Phillips, Andrew and and Justice, Amy and Tate, Janet and Bucher, Heiner C. and Egger, Matthias and and Furrer, Hansjakob and Miro, Jose M. and Casabona, Jordi and Porter, and Kholoud and Touloumi, Giota and Crane, Heidi and Costagliola, Dominique and and Saag, Michael and Hernan, Miguel A.",
    journal = "Statistics in Medicine",
    year = "2019",
    volume = "38",
    number = "13",
    pages = "2428-2446",
    publisher = "Wiley",
    issn = "0277-6715, 1097-0258",
    doi = "10.1002/sim.8120",
    keywords = "causal inference; dynamic regime; joint treatment strategies; marginal
structural model; no direct effect",
    abstract = "Decisions about when to start or switch a therapy often depend on the
frequency with which individuals are monitored or tested. For example,
the optimal time to switch antiretroviral therapy depends on the
frequency with which HIV-positive individuals have HIV RNA measured.
This paper describes an approach to use observational data for the
comparison of joint monitoring and treatment strategies and applies the
method to a clinically relevant question in HIV research: when can
monitoring frequency be decreased and when should individuals switch
from a first-line treatment regimen to a new regimen? We outline the
target trial that would compare the dynamic strategies of interest and
then describe how to emulate it using data from HIV-positive individuals
included in the HIV-CAUSAL Collaboration and the Centers for AIDS
Research Network of Integrated Clinical Systems. When, as in our
example, few individuals follow the dynamic strategies of interest over
long periods of follow-up, we describe how to leverage an additional
assumption: no direct effect of monitoring on the outcome of interest.
We compare our results with and without the “no direct effect”
assumption. We found little differences on survival and AIDS-free
survival between strategies where monitoring frequency was decreased at
a CD4 threshold of 350 cells/mu l compared with 500 cells/mu l and where
treatment was switched at an HIV-RNA threshold of 1000 copies/ml
compared with 200 copies/ml. The “no direct effect” assumption
resulted in efficiency improvements for the risk difference estimates
ranging from an 7- to 53-fold increase in the effective sample size."
}