Death rates after major surgery are similar regardless of whether a male or female surgeon operates on a male or female patient, finds a large US study published by The BMJ today.

The differences seen were small and not clinically meaningful and the researchers say their findings should help improve processes and patterns of care for all patients.

Gender concordance between patients and physicians (when the physician and patient are of the same sex) is generally linked to higher quality care processes and improved patient outcomes through more effective communication, reduced (implicit and explicit) sex and gender bias, and better rapport.

But evidence is limited about the effect of patient and surgeon gender concordance on outcomes of patients undergoing a surgical procedure.

To address this, researchers set out to determine whether patient-surgeon gender concordance is associated with death after surgery in the United States.

Their theory was that patients treated by surgeons of the same gender would have a lower postoperative death rate than patients treated by gender-discordant surgeons.

They analyzed data for almost 3 million Medicare patients aged 65-99 years who underwent one of 14 common major urgent or non-urgent (elective) surgeries between 2016 and 2019 including coronary artery bypass surgery, knee or hip replacement, hysterectomy, liver or lung resection, and thyroidectomy.

Death after surgery was defined as death within 30 days of the operation.

Adjustments were made for patient characteristics (such as age, race and underlying conditions), surgeon characteristics (such as age, years in practice and number of operations performed) and hospital fixed effects (effectively comparing patients within the same hospital).

Of 2,902,756 patients who had surgery, 1,287,845 (44%) had operations done by surgeons of the same gender (1,201,712 (41%) male patient and male surgeon and 86,133 (3%) female patient and female surgeon) and 1,614,911 (56%) were by surgeons of different gender (52,944 (1.8%) male patient and female surgeon and 1,561,967 (54%) female patient and male surgeon).

For urgent and elective procedures combined, the adjusted death rate 30 days after surgery was 2% for male patients treated by male surgeons, 1.7% for male patients treated by female surgeons, 1.5% for female patients treated by male surgeons, and 1.3% for female patients treated by female surgeons.

For elective procedures, female surgeons had slightly lower patient death rates (0.5%) than male surgeons (0.8%), whereas no difference in patient mortality was seen for urgent surgeries.

Several mechanisms could explain this small effect for elective procedures, say the authors. For example, female surgeons may abide by clinical guidelines more than male surgeons or might have better communication and increased attention to postoperative care than male surgeons, which could affect patient death rates.

What's more, as elective surgeries allow patients to choose their own surgeon, they are more prone to influence from other factors compared with urgent procedures where patients are assigned to on-call surgeons, they add.

This is an observational study, so can't establish cause, and the researchers stress that other unmeasured social and cultural factors may have influenced their results. What's more, they say their findings may not apply to younger populations, patients who receive less common procedures, or patients in other countries.

Nevertheless, they say understanding the underlying mechanisms of this observation "allows the opportunity to improve processes and patterns of care for all patients."

They add: "Ongoing qualitative and quantitative research will better delineate how surgeon and patient gender, along with race and other aspects of shared identity, affect quality of care and outcomes after surgery."