Thieves stole four unencrypted computers from an administrative building of the medical group.
Thieves stole four unencrypted computers from an administrative building of the medical group.

Millions of patients of the largest physician group in Chicago had their personal data stolen in an apparent burglary.

The breach occurred on July 15, when four computers were taken from Advocate Medical Group (AMG), which is part of Advocate Health Care, the largest health system in Illinois. According to an AMG news release sent to SCMagazine.com on Monday, the sensitive information of more than four million patients may be at risk as a result of the theft.

Compromised data includes names, Social Security numbers, dates of birth and addresses of patients, as well as “limited clinical information,” such as the names of physicians who treated individuals, diagnoses, medical record numbers, health insurance records and medical service codes, the release said.

The desktop computers did not contain full medical records or financial information of patients, but the data that was compromised was unencrypted, according to a website set up for impacted patients. The computers, which were taken from an administrative building in the Park Ridge suburb of Chicago, were password-protected.

It's not believed, however, that the machines were targeted for the information they contained, according to reports.

Following the burglary, AMG added round-the-clock security at the breached location and is determining which of its other facilities require similar surveillance.

AMG has more than 1,000 physicians and specialists at around 200 practices throughout Chicago and McLean County, Illinois. The medical group is offering patients free credit monitoring services, and began notifying individuals by letter on Friday, the site notice said.

Park Ridge police have yet to find the stolen computers, and are still investigating the incident. In the meantime, AMG set up a call center dedicated to impacted patients, in addition to the site, patientnotice.org.