What Is the Safest Day of the Week for Surgery?


Everyone who needs an operation (which eventually will include most of us) wants to be assured that it will be carried out in the best and safest conditions possible. All operations are serious for those having them; a minor operation, as the British physician George Pickering once put it, is an operation carried out on someone else.

Most people with the time or ability to search for the best hospitals, surgeons, etc., will not think of considering the day of the week on which the operation will be performed as a factor of safety. It has long been known that emergency operations done at night or on the weekends have worse results than those done during the day on weekdays; but what about routine or planned operations, those (the great majority) that can be done at the surgeon’s and hospital’s leisure, as it were?

A huge statistical study done in Britain and recently published in the British Medical Journal examined the 30 day death rates after all non-emergency operations performed between 2008 and 2011 (except day cases) according to the day on which the procedure was performed.

There were in total 27,582 deaths after 4,133,345 operations, a raw rate of 6.7 per 1000: a figure that by itself would have astonished our forebears, who were used to, and took as inevitable, death rates at least a hundred times higher.

What the researchers found was that people who underwent an operation on Fridays had a death rate 44 percent higher than those who underwent an operation on Mondays, while those who underwent an operation on the weekend had a death rate 82 percent higher.


Of course, the patients might have differed by more than the day of the week on which they were operated; but the authors corrected their figures for such factors as age, sex, ethnic group, comorbidities (i.e., the presence of other illnesses that might have affected outcomes), and numbers of medical emergencies in the last few years. They also corrected for economic status which they called “socioeconomic deprivation,” a term that is philosophically loaded. The difference remained after these adjustments.

They also broke down the death rates from operations of various categories. They examined the figures for hazardous operations such as removal of the stomach or oesophagus, colon, or lung, coronary artery bypass graft, or removal of abdominal aorta aneurysms. They examined the figures for what they called high-volume, low-risk operations such as hip and knee replacements, inguinal, femoral, and abdominal hernia repairs, and removal of the tonsils. The effect of the day of the week on the safety of the operation was constant.

They also found what to me was rather strange, that the death rate increased steadily as the week progressed. I do not think this can be accounted for by the authors’ preferred explanation, that patient care on the weekends is less good than during the week, since most of the risk of operation occurs immediately afterwards. Perhaps hospital staff, especially surgeons and nurses, grow steadily more tired or careless as the week progresses.

Be that as it may, the question arises what the average patient is supposed to do with this information. It goes without saying that not everyone who needs an operation can undergo an operation on Monday. So long as the information is not known by everyone, therefore, the wise patient would be well-advised to keep it to himself. A small number of patients, but not many, can ask for their operations on Monday and have their wishes respected. Knowledge is power, no doubt, but in this case only if it is not knowledge that not everyone shares.


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