A damning review of the island's rheumatology service has concluded it is 'well below' the standard of a 'contemporary' clinic.
The Royal College of Physicians investigated the workings of two doctors, referred to in its report as Dr Y and Dr Z, after concerns were raised by a junior doctor in January 2022.
The RCP review found that the prescriptions did not comply with either UK or EU guidelines.
Biologics are immunosuppressant drugs, used to treat several conditions, such as arthritis, cancer and Crohn's Disease.
The RCP instructed Health and Community Services to do an audit of all patients who had been prescribed biologic medication.
341 people were on the medication at the time of the review. Doctors found that half had no evidence to support them taking biologics, with one in four now having their biologic care stopped.
The review also looked into the rheumatology service as a whole and found that it lacked good governance, as did the entire healthcare organisation.
The rheumatology service specifically had no 'expected audits and bench-marking processes' that would be found in modern services.
23 recommendations have been made including having a 'more holistic' approach to care, with exercise classes and education sessions offered to newly-diagnosed patients.
The RCP has also recommended that the two doctors' concerned should not be able to provide rheumatology care independently in HCS, privately or in the NHS.
Dr Z no longer works with Jersey's health system. While Dr Y is still employed by HCS, the department says that they have restrictions on what they can perform, including not being able to prescribe drugs, and they must get approval before being able to work in non-HCS environments.
Chris Bown, HCS Chief Officer, says it's not a service anyone could be proud of.
"The people of Jersey deserve better, and we are deeply sorry that we did not provide a service that staff, patients and our community could be satisfied with.
A number of patients have had changes to diagnoses or medications as a result of the work we have undertaken and it is inevitable that some of these patients will have been harmed clinically, emotionally and/or economically by their earlier diagnosis or treatment.
We expect that in most cases the level of harm will be minor or negligible but, of course, any level of harm is completely unacceptable."
The department is consulting its lawyers about compensation.