Patients treated by a female physician are less likely to die or to be readmitted to hospital than those treated by a physician who is male, according to a new study by a team of researchers from the US and Japan.

And if the patient happens to also be female, the difference is even more pronounced, especially so when they're severely ill.

While this study doesn't dive deeply into the reasons for the disparity, it supports previous research that comes to similar conclusions.

"What our findings indicate is that female and male physicians practice medicine differently, and these differences have a meaningful impact on patients' health outcomes," says Yusuke Tsugawa, a health policy scientist at the University of California, Los Angeles (UCLA).

The team analyzed data from US Medicare sources describing 458,108 female and 318,819 male patients hospitalized between 2016 and 2019. All patients were over the age of 65, and just under a third of both male and female patients were seen by female physicians.

This info was then referenced against 30-day mortality rates (from the date of admission) and 30-day readmission rates (from the date of discharge). In both cases, female doctors led to better outcomes.

While the differences don't show direct cause and effect, and weren't huge – adjusted mortality rates of 8.15 percent (female doctor) vs 8.38 percent (male doctor) for female patients, for example – they represent a statistically significant gap that shouldn't be there at all. To put that difference into perspective, it amounts to 1 death for every 417 hospitalizations.

"A better understanding of this topic could lead to the development of interventions that effectively improve patient care," says Tsugawa.

"It is important to note that female physicians provide high-quality care, and therefore, having more female physicians benefits patients from a societal point-of-view."

The study authors suggest several reasons could be behind the discrepancies, which have been spotted before in different medical scenarios. It's possible that female doctors communicate better with female patients, the researchers say, or that male doctors are more likely to underestimate the severity of conditions experienced by female patients.

There might also be less embarrassment and discomfort between female doctors and female patients, the research team suggests, meaning more honesty about certain conditions and improved diagnosis and treatment.

The researchers want to see more done to improve sex diversity in hospital settings, and to make sure the quality of care is the same no matter whether patients or physicians are male or female – and for that to happen, more studies will be needed looking at why the differences exist.

"Further research on the underlying mechanisms linking physician gender with patient outcomes, and why the benefit of receiving the treatment from female physicians is larger for female patients, has the potential to improve patient outcomes across the board," says Tsugawa.

The research has been published in the Annals of Internal Medicine.