Dr Hepburn said steps had been taken to prevent patients' data from being downloaded
Hull and East Yorkshire Hospitals NHS Trust has apologised after confidential data of more than 1,000 patients was stolen from a doctor's home.
The trust said the medic broke regulations by taking away the unencrypted medical records and was now facing a disciplinary hearing.
The information was contained on a laptop and was stolen from the doctor's home in November.
It includes patients' names, dates of birth and hospital treatment.
Mary Holmes, 12, is among the patients whose records were stolen.
Her mother Cathie said she wanted to see changes to ensure other patients did not end up in a similar situation.
"Things that you wouldn't tell anyone else you'd tell a doctor because you know they can't or they are not supposed to share information elsewhere," she said.
"But now some bloke at the end of the road could have Mary's details and know exactly what treatment she receives."
'Non-encrypted laptop'
Dr David Hepburn, medical director for Hull and East Yorkshire NHS Trust, said steps had been taken to prevent patient details being downloaded from computers but it was more difficult to control information being sent by email.
"This particular employer used email to send the information to himself and then stored it on a non-encrypted laptop."
Mr Hepburn added: "We have already written to anyone affected by this to inform them of these incidents and therefore anyone who has not received a letter has no cause for concern.
"The trust takes data protection issues very seriously and this member of staff is currently the subject of a disciplinary process."
