Body mass index (BMI) and overall survival (OS) among Hispanic patients treated with immune checkpoint inhibitors (ICIs).

11171 Background: Prior studies have suggested improved OS among cancer patients receiving ICIs with higher BMI, despite obesity being a known cancer risk factor; however, these findings are largely derived from predominantly non-Hispanic cohorts. In Austin, Texas, Hispanic individuals comprise approximately 30% of the population, limiting the external validity of prior studies. We evaluated whether the previously described association between BMI and OS extends to Hispanic patients treated with ICIs. Methods: We retrospectively identified Hispanic patients with solid tumors treated with ICIs at Ascension/UT Health Austin between November 2013 and December 2025 using Research Electronic Data Capture (REDCap) data. BMI at ICI initiation was categorized as normal (18.5–24.9 kg/m²), overweight (25–29.9 kg/m²), or obese (≥30 kg/m²); underweight patients were excluded. Overall survival (OS) was defined as time from ICI initiation to death, with censoring at last follow-up or 5 years. Missing 5-year survival status was addressed using single stochastic regression imputation. Stabilized inverse probability of treatment weighting from a multinomial propensity score model was used to adjust for baseline differences, including age, sex, ECOG status, cancer type and stage, ICI agent, steroid exposure, and antibiotic exposure. Weighted Cox proportional hazards models estimated associations between BMI and OS, with prespecified subgroup analyses by sex and stage. Results: Among 177 Hispanic patients included, average age was 54 years and 53% were male; 32% had normal BMI, 31% were overweight, and 37% were obese. Median overall survival (OS) was 497 days. After inverse probability weighting, BMI was not associated with OS (p = 0.90). Compared with normal BMI, overweight patients had a hazard ratio (HR) of 0.94 (95% CI 0.49–1.80) and obese patients an HR of 1.09 (95% CI 0.60–2.00). No significant differences were observed between obese and overweight patients (HR 1.16; 95% CI 0.64–2.09). Subgroup analyses by sex and cancer stage showed no survival advantage associated with higher BMI. Among women, obese patients had an HR of 1.58 (95% CI 0.49–5.13), while among men the HR was 1.30 (95% CI 0.66–2.58). When stratified by stage, obese patients had an HR of 1.68 (95% CI 0.44–6.40) in stages I–III and 1.13 (95% CI 0.53–2.40) in stage IV. Conclusions: In this cohort of Hispanic patients with solid tumors treated with immune checkpoint inhibitors, we did not find a survival advantage for those with higher BMI. These findings raise the possibility that BMI associated survival advantages reported in predominantly non-Hispanic cohorts may not extend to the Hispanic population. Larger studies are needed to determine whether these findings represent true population-specific differences.