The Role of Body Mass Index in Brain Tumor Surgical Outcomes: Does the Obesity Paradox Hold True?

Introduction: The obesity paradox, a phenomenon in which overweight patients demonstrate better outcomes than those who have a normal weight, is well described in the cardiometabolic literature but less well so in oncology. This study aims to clarify this association by analyzing the impact of BMI on hospital course and short-term outcomes of patients who have undergone brain tumor surgery.

Methods: This preliminary retrospective study reviewed all operative brain tumor cases from 2013 to 2024 at New England’s largest safety-net hospital and Level 1 trauma center. We collected demographic, clinical, and outcome data for each patient. BMI was analyzed both as a continuous variable and as a categorical variable, dividing patients into healthy (BMI < 25 kg/m²) and unhealthy (BMI ≥ 25 kg/m²) groups.

Results: A total of 215 patients with a mean age of 52.9 were included. The cohort was 53% female, 61% non-White, and 35% primarily non-English speaking. Tumor types included 18.6% high-grade glioma, 28.4% meningioma, 20.9% pituitary adenoma, 19.5% metastases, and 12.6% other. An unhealthy BMI was significantly more common among females (p < 0.01), primarily non-English speaking patients compared to English speakers (p = 0.04), and patients who lived farther from the hospital (p = 0.047). Patients with unhealthy BMIs had significantly higher albumin levels (p = 0.01) and Karnofsky Performance Scale (KPS) scores (p = 0.02) at diagnosis, as well as longer hospital stays (p = 0.048). However, there were no significant differences in post-operative complications (p = 0.35), KPS (p = 0.85), modified Rankin Scale (mRS) (p = 0.74), Eastern Cooperative Oncology Group (ECOG) (p = 0.74) scores at discharge, or survival (p = 0.35). Notably, 5.7% of patients with an unhealthy BMI at diagnosis had a healthy BMI at discharge.

Conclusion : Although our analysis did not reveal any significant differences in hospital course and short-term outcomes, a more thorough exploration of the relationship between BMI and surgical outcomes in brain tumor patients is needed to determine if the obesity paradox holds true.