Stewart Kelly, 45, died at Robina Hospital in August 2022, 33 days after he was admitted for a medical condition, according to ABC News.
Gold Coast Hospital and Health Service chief executive Ron Calvert says staff at the hospital "should have done better".
"We acknowledge that there were significant failings in this patient's care," he told reporters on Wednesday.
"I do believe his death was preventable and I offer my unreserved apologies to his family for this."
The Office of the Health Ombudsman is investigating Mr Kelly's death.
Mr Calvert said no staff member was individually culpable and it was a very complex case and "a lot of people could have done it differently.
He said work was underway to improve treatment and support for neurodiverse patients.
Compensation has not been offered to Mr Kelly's family but Mr Calvert said it was open to them to seek legal advice.
"Particularly based on the fact that we've clearly indicated the level of mistakes we made," he said.
"I'm sure they're likely to meet with success."
Mr Kelly was admitted for a medical condition and also had "psychiatric issues".
Deputy Executive Director of Medical Services Bav Manoharan said staff initially failed to identify that Mr Kelly was deteriorating and escalate his case for treatment.
"Once that escalation occurred, the care that was provided was appropriate," he said.
Dr Manoharan said it was difficult to provide care to patients with complex neurodiverse issues and acute medical issues.
A review made 11 recommendations and listed five lessons the hospital has committed to implementing.
"Some of those relate to how we internally communicate within the hospital, how we make referrals between treating teams," Dr Manoharan said.
Others concerned how care is escalated when a patient's health is deteriorating and how patients with neurodiverse issues are managed.
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