A hacking incident at the University of New Mexico Health in Ålbuquerque exposed the information of 637,252 patients, according to data recently reported to HHS.
The health system began notifying patients who may have been affected Aug. 3.
On June 4, the health system discovered that an unauthorized third party gained access to its network and may have obtained files containing patient information May 2.
The exposed files contained patient names, addresses, birthdates, medical record numbers and health insurance details. Some patients' Social Security numbers were exposed, according to the online privacy notice.
The health system said it is providing free credit- and identity-monitoring services to patients whose Social Security numbers were exposed.