The weight of risk: BMI and postoperative outcomes in older adults with sepsis undergoing emergency laparotomy

Older adults with sepsis undergoing emergency laparotomy face high postoperative risk. We aimed to evaluate the association between body mass index and postoperative outcomes in this high-risk population.

We used American College of Surgeons National Surgical Quality Improvement Program 2013-2017 to identify patients aged ≥65 years who underwent emergency exploratory laparotomy with preoperative sepsis. Body mass index was categorized into 6 standard groups. The primary outcome was 30-day mortality. Secondary outcomes included in-hospital mortality, respiratory complications, pulmonary embolism, and other National Surgical Quality Improvement Program-defined complications. Multivariable logistic regression evaluated associations between body mass index and outcomes adjusting for demographics, American Society of Anesthesiologists class, frailty, comorbidities, albumin and creatinine, operative time, and septic shock status. A septic shock subgroup analysis was prespecified.

Among 3,191 older adult patients with sepsis who underwent emergency laparotomy, 30-day mortality was 31.6%. Compared with normal body mass index, obesity class II was associated with lower 30-day mortality (adjusted odds ratio 0.55, 95% confidence interval 0.37-0.83) and in-hospital mortality (0.63, 0.41-0.96) but higher odds of ventilator dependence >48 hours (1.48, 1.05-2.09) and deep vein thrombosis (2.00, 1.06-3.77). Obesity class III was associated with deep vein thrombosis (adjusted odds ratio 1.98, 95% confidence interval 1.02-3.83), pulmonary embolism (5.55, 2.10-14.67), and nonhome discharge (3.31, 1.96-5.57). Underweight was associated with unplanned reintubation (adjusted odds ratio 1.68, 95% confidence interval 1.02-2.75). In the septic shock subgroup (33.6% of the cohort, n = 1,072), obesity class II remained associated with lower 30-day mortality (adjusted odds ratio 0.43, 95% confidence interval 0.24-0.76).

In older adults with sepsis undergoing emergency laparotomy, obesity class II was associated with lower mortality but higher odds of ventilator dependence >48 hours and deep vein thrombosis. Obesity class III was associated with higher odds of deep vein thrombosis, pulmonary embolism, and nonhome discharge. These findings highlight the complex relationship between body mass index and postoperative outcomes in this high-risk population.