PATIENTS who undergo operations on their surgeon's birthday are 23 per cent more likely to die than patients who have surgery on other days, according to a new study.

Researchers in Los Angeles pointed to evidence of similar trends around the world, including a study in Scotland which previously found that patients admitted as emergencies to Dumfries and Galloway Royal Infirmary on a public holiday were 48% more likely to die within seven days of surgery, and 27% more likely to die within 30 days.

The paper, published today in the British Medical Journal, is the first time a potential link between surgeons' birthdays and patient mortality has been investigated.

The researchers compared more than 980,000 common procedures performed by nearly 48,000 surgeons in US hospitals between 2011 and 2014.

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Of these, 2,064 were performed on the surgeons birthday, with 145 patients dying within a month of their operation. In the non-birthday cohort, there were 54,824 deaths out of 978,812 surgeries.

The analysis covered 17 common operations, including heart surgeries, lung resections, hip fracture repairs, or appendix removals.

All patients had been admitted to hospital as emergency or urgent cases, and were aged 65 to 99 years old.

Patients who underwent operations on surgeons’ birthdays had similar characteristics to those who underwent operations on other days, including age, severity of illness and underlying health conditions.

Their likelihood of dying within 30 days of surgery - known as the predicted mortality rate - was also fractionally lower than patients undergoing operations on other days, at 5.5% versus 5.6%.

However, once adjusting for any differences in the patients' risk factors and even comparing the outcomes for patients treated by the same surgeon on different days, the researchers discovered that the 30-day mortality rate for patients admitted to theatre on their surgeon's birthday was actually 6.9%, compared to the predicted 5.6% for other patients.

This suggests that a surgeon's birthday increases their patients' mortality risk by 23%.

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The researchers note that while this is "substantial" it is also "comparable to the impact of other events, including holidays (eg, Christmas and New Year) and weekends, which have been argued to affect the quality of patient care".

However, they found no evidence for patient mortality being higher on surgeons’ birthdays in relation to elective procedures.

Outside of healthcare, studies have found that factors such as heatwaves and losses of local sports teams can impact poorly on decision making.

The researchers suggest the findings might be explained by surgeons "feeling rushed to complete procedures on time"due to birthday celebrations planned for the evening "which could lead to a higher likelihood of errors and overlooking signals of clinical deterioration in patients".

They say "distracting" birthday conversations with theatre colleagues during surgery might lead to medical errors, or that surgeons "may receive birthday messages on their phones in the operating room", more so than other days, "which can be a potential source of distraction".

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Laboratory experiments have shown that distractions can have a detrimental effect on surgeons’ performance, such as time to task completion, surgical errors, and accuracy.

The researchers add: "It is possible that surgeons might allow surgical trainees to do more on the surgeon’s birthday in order to get home early

"Finally, it is also possible that postoperative care decisions could differ on surgeons’ birthdays.

"For example, surgeons may be less likely to return to the hospital to see their patients who show signs of deterioration if they are having dinner with family and friends, compared with regular evenings."