LOS ANGELES (AP) — UCLA’s system of hospitals and clinics warned more than 16,000 patients that their personal information was on a computer hard drive stolen in the burglary of a doctor’s home, officials said Friday.

The UCLA Health System sent letters to the 16,288 patients affected, warning them of possible identity theft and giving them contact information for a data security company the system has enlisted for help.

Someone using the documents for identity theft was “very unlikely,” but there was a possibility, the statement said.

“UCLA’s concern for its patients is absolute, and we deeply regret any breach of confidentiality and the stress and concern it might cause,” it said.