Large study finds prolonged fasting for multiple orthopedic surgeries raises risk of malnutrition, worse outcomes

People who have multiple orthopedic surgeries during the same hospital stay are more likely to suffer malnutrition due to repeated or prolonged fasting, which can slow recovery and increase the risk of death, according to a study of more than 28 million patients presented at the ANESTHESIOLOGY 2024 annual meeting.

Because food or liquid retained in the stomach increases the risk of regurgitation and aspiration in the airway and lungs during general anesthesia and deep sedation, most patients are directed to fast for at least eight hours before surgery.

This is generally accomplished by not eating after midnight. It is also recommended that only clear liquids may be consumed up to two hours before the procedure. Patients having multiple surgeries while in the hospital, especially those clustered together over several days, are required to fast repeatedly or for cumulative prolonged periods.

“Our research determined that repeated fasting in hospitalized patients having multiple orthopedic surgeries over days or weeks increases the risk for protein-calorie malnutrition, leading to longer hospital stays, slower recovery and higher health care costs,” said Ivie Izekor, B.S., lead author of the study and a fourth-year medical student at Texas A&M College of Medicine, Bryan.

“While fasting is a crucial part of ensuring patients’ safety during surgery, our findings suggest modifications to clinical practice should be considered for patients who are at risk for malnourishment, such as those who are older than 65, have a chronic illness like diabetes or congestive heart failure or have limited access to adequate nutrition prior to surgery for socioeconomic reasons.

“Patients who have frequent surgeries or hospital stays and those with conditions that impair nutrition absorption also are likely at higher risk.”

For the study, researchers analyzed the National Inpatient Sample database between 2016 and 2019. They identified 28,475,485 patients who had orthopedic surgery of any type in the hospital, 1,853,360 (6.5%) of whom were diagnosed with malnutrition after admission.

Patients were grouped based on the number of surgeries they had, all of which were performed during a single hospitalization. Patients who were diagnosed with malnutrition had an average of 2.31 surgeries, while those who were not malnourished had an average of 1.57 surgeries.

Researchers found malnourished patients:

• were at least 15% more likely to die (and the risk increased with more surgeries),
• had higher hospital costs (an average of $98,000 vs. $48,000) and
• had longer hospital stays (an average of 9.07 days vs. 4.34 days).

The cause of death in malnourished patients typically was related to infection, complications from poor wound healing or general frailty exacerbated by malnutrition. Researchers chose orthopedic surgeries because they do not directly involve the gastrointestinal system, which could complicate the findings.

Patients who have multiple orthopedic surgeries include those with chronic joint conditions such as osteoarthritis, traumatic injuries that require several stages of repair and those needing revisions of initial surgeries.

To prevent malnutrition, researchers suggest that patients undergoing multiple surgeries receive personalized nutritional support during their hospital stay. This support may include dietary assessments by a dietitian, nutritional supplementation, and monitoring nutritional status to help facilitate faster recovery and reduce complications.

“The combined effects of repeated fasting and surgical stress can compromise nutritional status, regardless of the type of surgery, and it is likely our findings would hold true for patients undergoing multiple surgeries of any type,” said George Williams, M.D., FASA, FCCM, FCCP, senior author of the study and professor and vice chair of critical care medicine in the Department of Anesthesiology and Pain Medicine at McGovern Medical School, UT Health, Houston.

“However, it may be more challenging to assess the cause-and-effect relationship in gastrointestinal surgeries due to their direct impact on the digestive system.”

Provided by
American Society of Anesthesiologists