Using observational data to emulate a randomized trial of dynamic treatment-switching strategies: an application to antiretroviral therapy. International Journal of Epidemiology
Cain et al. reviewed a framework for the comparison of dynamic switching strategies using observational data from 43’803 HIV-infected individuals. In this hypothetical randomized trial, individuals were randomized to either switch antiretroviral therapy (ART) within 90 days of HIV-1 RNA crossing above 400 copies/ml (tight-control group) compared to a switch within 90 days of HIV-1 RNA crossing above 1000 copies/ml (loose-control group). There were 21 deaths and 33 AIDS or death events in the tight-control group, and 28 deaths and 41 AIDS or death events in the loose-control group. Compared with tight control, the fully adjusted hazard ratios for loose control were 1.10 for death and 1.04 for AIDS or death.
In conclusion, this approach detected little or no differences between switching at HIV-1 RNA thresholds of 400 and 1000 copies/ml in preventing death and AIDS-defining illness.