FARGO, N.D. — Essentia Health in Fargo has apologized for giving the names and mailing addresses of hundreds of patients to a private marketing company.

The breach came to light in June when about 430 patients received a letter inviting them to a seminar for people with lower back pain. At least one woman complained, and Essentia last week sent out letters acknowledging the breach and apologizing, reports said.

Essentia said no patient medical information was involved and that it goes to great lengths to protect patient health information. The hospital said in a statement that it is reviewing what happened and educating employees so that a similar incident does not happen again.

Essentia also said it did not sell the names and addresses, and that the marketing company has since returned the information.

Jodine Wien received one of the letters and complained to Essentia. She said an apology doesn’t fix what happened.

“I’m angry. I’m saddened,” the Moorhead resident said. “I feel that I’ve lost trust in Essentia itself, and that has been my primary medical facility for many, many years.”