Being overweight may protect against mortality following surgery in older adults

Among older adults who are undergoing major elective surgery, those who are overweight may have lower mortality after the procedure compared with those who have normal weight, as suggested in a study.

The study included 414 older adults (mean age 75.9 years, 54.8 percent female) scheduled for a major elective surgery. BMI was <18.5 kg/m² in 20 participants (underweight), 18.6–24.9 kg/m² in 133 (normal weight), 25–29.9 kg/m² in 128 (overweight), 30–39.9 kg/m² in 109 (obese), and ≥40 kg/m² in 24 (morbidly obese). Of the participants, 24.2 percent had frailty, and 37 percent were prefrail.

Outcomes included postoperative 30-day and 1-year all-cause mortality, and postoperative delirium, discharge disposition, and complications classified using the Clavien-Dindo system.

The rate of all-cause mortality was 11 percent at 30 days and 17 percent at 1 year. Compared with normal weight, underweight was associated with significantly increased odds of 30-day (75 percent vs 18.8 percent; odds ratio [OR], 21.81, 95 percent confidence interval [CI], 6.24–76.21; p<0.001) and 1-year mortality (80 percent vs 28.6 percent; OR, 12.40, 95 percent CI, 3.70–41.61; p<0.001).

In contrast, overweight was associated with reduced odds of mortality at 30 days (0.8 percent; OR, 0.03, 95 percent CI, 0.00–0.23; p=0.001) and 1 year (5.5 percent vs 28.6 percent; OR, 0.13, 95 percent CI, 0.06–0.32; p<0.001).

Results were the same for obesity, with lower odds of 30-day (0.9 percent; OR, 0.03, 95 percent CI, 0.00–0.24; p=0.001) and 1-year mortality (4.6 percent; OR, 0.10, 95 percent CI, 0.04–0.28; p<0.001).

Postoperative complications occurred with the least frequency among overweight patients, with just 16 percent experiencing any complication. 

The present data suggest that traditional weight loss recommendations based on achieving normal BMI may need to be re-evaluated for this population.