Patients operated on by female surgeons have slightly lower death rates than those treated by men, research suggests.

A new study in the British Medical Journal (BMJ) found a small but significant reduction in death rates of 12% for those patients treated by women compared with men.

But there was no difference between the sexes when it came to patients experiencing readmission to hospital or complications within 30 days.

The researchers, including from the University of Toronto, analysed data for more than 100,000 patients undergoing one of 25 surgical procedures in the same hospital in Ontario, Canada.

The patients were matched for age, sex, range of conditions and income, while surgeons were matched for age, experience and number of operations performed in the last year.

The authors suggested one possible reason for the difference may be that women deliver care that is more in line with guidelines, is more focused on the patient, and involves better communication.

But they said more research was needed.

They concluded: "These findings support the need for further examination of the surgical outcomes and mechanisms related to physicians and the underlying processes and patterns of care to improve mortality, complications, and readmissions for all patients."

In an editorial, Clare Marx and Derek Alderson, from the Royal College of Surgeons of England, said the sex of the surgeon is unlikely to be relevant and the study did not look at longer-term effects for the patient.

They said they were not convinced that the sex of the surgeon "will emerge as an important determinant of a good outcome for patients having surgery".