Several studies suggest that point to the possibility that bariatric surgery may cause symptomatic hypoglycemia to occur. In a controlled study of 45 patients, episodes of hypoglycemia after bariatric surgery were standard although primarily unnoticed by patients.

About the Study

The three-day average current period of patients showed that 22% of the 15 patients who had undergone Roux-en-Y gastric bypass surgery and 20% of the 15 patients who had undergone biliopancreatic diversion with duodenal switch, had symptomatic hypoglycemias. Of the 45 total patients monitored, 15 of them did not go through surgery and were nondiabetic. These 15 did not show any symptoms of hypoglycemia usually present.

The Results

Through monitoring of the glucose levels in the patients after surgery, it is clear that many of them spent significant time in hypoglycemia. The patients studied after gastric bypass surgery had a glucose level lower than 3.3 mmol/L for an average of 42 minutes per day and lower than 2.8 mmol/L for 21 minutes per day.

Those patients who underwent duodenal switch surgery had a glucose level of lower than 3.3 mmol/L for an average of 85 minutes per day and a glucose level of less than 2.8 mmol/L for an average of 39 minutes per day. This is compared to low glucose levels in the patients who did not have surgery.

These numbers were surprising and changed the way that specialists in bariatric surgery might think about their patients. These figures are widely unnoticed without directly looking for them. This can be dangerous, and a change in what to watch for in patients undergoing surgeries is necessary.


Hypoglycemia can improve brain function, motor function, and cognition. It is vital that proper monitoring is accomplished in patients who go through bariatric surgeries. Monitoring glucose levels in non-diabetic patients may need to be a major part of the post-surgical procedure for the patients.

The differences in post-op gastric bypass patients might be different than those of the post-op duodenal switch patients. The evidence is clear that the approach to the patients after surgery should change. It is not typically a standard procedure to monitor glucose levels in patients who are not diabetic. Making sure that these levels are observed is vital to the continued safety of bariatric surgery.

It is also important to continue the research to find out exactly what the factors are that cause hypoglycemia to occur in these patients. There may be something that is triggering the issue that can be changed to reduce the instances.

Risks of Hypoglycemia

It is also important that the risk of hypoglycemia in patients is explained pre-surgery to the patient. They will need to know that this is a risk factor just as they understand the other risks of the surgery. Patients will need to know what may happen and what the statistics are relating to hypoglycemia.

The fact that the hypoglycemia is not noticed by the patient and only noted when glucose levels are monitored post-surgery doesn’t make it less vital to the post-surgery monitoring process or any less essential when it comes to assessing the risks.