Study Finds Overweight Status May Aid Older Adults in Surgery Recovery

Older adults who are overweight could face a lower risk of death in the first 30 days following major optional surgery compared to individuals with a normal body mass index (BMI), according to research conducted by investigators from the David Geffen School of Medicine at the University of California (UCLA). The study authors, who published their findings in JAMA Network Open, noted that traditional BMI risk categories possibly need to be updated for adults aged 65 years and older who are undergoing surgery.^1,2

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“Traditional surgical guidelines often emphasize having a normal BMI before surgery, but our findings suggest that these recommendations may need to be reconsidered for older adults,” Cecilia Canales, MD, lead study author and assistant professor in the Department of Anesthesiology & Perioperative Medicine at the David Geffen School of Medicine at UCLA, said in the news release. “Older adults have different physiological considerations, and moderate excess weight may actually be protective in the short term after surgery.”²

High BMI Linked to Increased Postoperative Complications

A BMI ranging from 25 to 35 places individuals in the categories of being overweight, obese, and morbidly obese, which has been previously linked with an increased risk of chronic conditions, along with a decreased life expectancy. Additionally, high BMI has also been related to increased postoperative complications, including blood loss, infection, and thromboembolic impacts. Greater postoperative mortality in certain individuals with a high BMI has led surgical clinicians to recommend weight loss prior to receiving operations to reduce obesity-related deaths.¹

For older adults, the connection between BMI and surgical outcomes is not fully understood. This is because age-related physiological changes may alter how BMI impacts health. However, the study authors noted that there is an ongoing question about whether it’s appropriate for overweight older adults to lose weight before surgery.¹

Could Older Postoperative Adults Benefit From a Higher BMI?

Researchers conducted a longitudinal cohort study at a large academic center in Southern California to investigate if higher BMI in older adults would be linked to a lower risk of death after major elective surgery between February 2019 and January 2022.^1,2

A total of 414 adults aged 65 years and older were included in the study, with a mean age of 75.9 years. Individuals were categorized by BMI and compared for 30-day and 1-year mortality, postoperative delirium, discharge disposition, and complications. The study authors noted that 24.2% of the participants were frail, and 37% were prefrail. The overall 30-day mortality rate was 110%.^1,2

The results demonstrated that the lowest death rate was found in overweight patients, with only 0.8% of them dying within 30 days, a significant reduction compared to the 18.8% mortality rate for those with a normal BMI. Additionally, the highest mortality rate, at 75%, was among underweight patients.^1,2

The findings suggest that the standard advice for this population to lose weight and achieve a normal BMI might need to be reconsidered.^1,2

“This study adds to a growing body of evidence on the so-called ‘obesity paradox,’ where a higher BMI appears to be linked with better survival in certain older adult populations,” Catherine Sarkisian, MD, coauthor and professor of medicine in the division of general internal medicine and health services research at the Geffen School, said in the news release. “It’s important to tailor preoperative evaluation to the physiology of older patients.”²

REFERENCES

1. Canales C, Anderson M, Elashoff D, et al. Body Mass Index and Postsurgical Outcomes in Older Adults. JAMA Netw Open. 2025;8(8):e2528875. doi:10.1001/jamanetworkopen.2025.28875.

2. Overweight older adults face lower risk of death after major surgery. EurekAlert! News release. August 26, 2025. Accessed September 15, 2025. https://www.eurekalert.org/news-releases/1095598