Regulatory Focus™ > News Articles > For First Time Since Founding, Government's Mini-Sentinel System Shrinks in Size

For First Time Since Founding, Government's Mini-Sentinel System Shrinks in Size

Posted 13 May 2014 | By Alexander Gaffney, RAC

The US government's Mini-Sentinel adverse event active surveillance system had something unusual happen to it this year: It shrank.


Mini-Sentinel was created in 2008 as an effort to create a nationwide system to track products regulated by FDA after their approval. With the Food and Drug Administration Amendments Act (FDAAA) placing a far greater emphasis on post-approval requirements for drugs (instead of requiring all data to be submitted prior to approval), regulators and legislators realized FDA needed a way of keeping better track of adverse events to inform their ongoing assessments of product safety.

In order to do that, FDAAA called for the creation of a system capable of compiling and analyzing huge swaths of healthcare data, and in 2010 the Mini-Sentinel system was born.

While the system is technically independent of the US Food and Drug Administration (FDA), it remains closely aligned with the agency and frequently releases reports at its request, and using expertise provided by the agency.

Big, Big Data

As Focus reported earlier this year, the system has become enormous since its launch in 2010. As of July 2012, the Mini-Sentinel Distributed Database (MSDD) included information on 160 million individuals, 3.5 billion medication dispensings and 3.8 billion unique medical encounters-data it obtains from more than a dozen healthcare providers.

The size of the database encompasses about half the entire population of the US, which stood at 314 million in 2012.

But according to new data, the database actually shrank in 2013 for the first time since it was established.

As of 22 August 2013, the database contained information on 150 million individuals-a decrease of about 10 million relative to the year prior, though still well above its standing as of December 2011 (126 million).

But while MSDD's data may have covered fewer individuals, several other areas grew in ways indicating that it's building a more robust profile about those who remain.

For example, MSDD now contains information regarding 3.9 billion prescription drug dispensings, up from 3.5 billion the year prior. In addition, the database now has information about 4 billion medical encounters, up from 3.8 billion the year prior.

While no explanation was given for the drop-off, prior reports have indicated that sudden drops are due to data partners no longer participating in the program. A scan in the anonymized records provided by Mini-Sentinel indicate that one of its largest participating organizations either dropped out entirely or significantly reduced the number of records it was providing in 2013.

A breakdown of the Mini-Sentinel reports from all four years is provided below for your convenience.

Mini-Sentinel Data at a Glance
Fall 2010December 2011July 2012August 2013
Individuals (Millions)62126160150
Years of Observation Time230345407356
Individuals Currently Enrolled (Millions)31435249
Individuals With >3 Years of Data (Millions)19273435
Dispensings (Billions)233.53.9
Dispensings Per Month (Millions)30374545
Unique Encounters (Billions)
Acute Inpatient Stays  (Millions)54404341
Encounters Per Month (Millions)30415751
Individuals With >1 Lab Result (Millions)N/A12.6N/A24.7
Number of Data Partners15171818
Link to ReportHereHereHereHere

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