Patients who visited Sutter Health 's Alta Bates Summit Medical Center , Sutter Delta Medical Center , or Eden Medical Center may have had their names , Social Security numbers , dates of birth , gender , addresses , zip codes , home phone numbers , marital status , names of employers , and work phone numbers exposed . The Alameda County Sheriff 's office notified Sutter Health of the potential breach on May 23 . It is unclear what the source of the breach might be . UPDATE ( 06/10/2013 ): The information was found during a narcotics raid . The personal information of nearly 4,500 patients was discovered . ;