I guess that the iDMC (stands for independent Data Monitoring Committee) has been used for a while, however, I first time heard the terms iSTAT and iDM in the recent data monitoring committee conference. iSTAT stands for independent Statistician and iDM stands for independent Data Management.
To support the iDMC who could review the interim data during the study, an independent statistical programming team is typically needed. Within the same organization (sponsor or CRO), there could be two teams: one is the study team and is always blinded to the study treatment (prior to the study unblinding) and one is the independent team that could have access to the randomization codes and prepare the unblinded interim information for iDMC.
Currently there are many different structures in arranging the iDMC operation with statistical support. The iSTAT could be with the sponsor, with CROs (contract research organization), or ARO (academic research organization). Each modol has its own pros and cons.
IS (independent statistician). See the talk about Pat O'meara
IDC (independent data center)