(1588) Obesity and Short-Term Mortality in Traumatic Brain Injury Patients: A Population-Level Study

Introduction: Obesity is associated with reduced life expectancy. However, research investigating the impact of obesity on short-term mortality following traumatic brain injury (TBI) has produced inconclusive findings.

Methods: We analyzed publicly available, statewide, and deidentified hospitalization records from 2016 to 2021 of trauma and emergency patients aged ≥18 years with a principal diagnosis of an initial encounter for TBI admitted to the intensive care unit (ICU) at acute care hospitals in Texas. We identified obesity and TBI cases using International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes from the Clinical Classification Software Refined (CCSR) database, (END009 for Obesity and INJ008 for TBI). To assess the association between obesity and short-term mortality (in-hospital mortality or discharge to hospice), we employed three modeling approaches. The primary approach utilized multilevel logistic regression with propensity score matching. Alternative analyses utilized multivariable logistic regression without propensity score matching. Additional analyses were performed for patient subgroups, categories of hospitalizations, and for in-hospital mortality.

Results: Of 62,070 hospitalizations with a diagnosis of TBI, 3,550 (5.7%) had a diagnosis of obesity. Hospitalizations with obesity, compared to those without obesity, exhibited a higher prevalence of comorbidities, including congestive heart failure (19.5% vs 10.9%), diabetes (44.2% vs 23.2%), chronic lung disease (15.3% vs 9.4%) and renal disease (18.1% vs 11.1%) (p < 0.0001). Patients with obesity showed an unadjusted short-term mortality of 11.1% compared to 15.2% for non-obese patients. On adjusted analyses, obesity remained associated with lower odds of short-term mortality (adjusted odds ratio 0.6376 [95% CI 0.5480–0.7419]). The results were similar across alternative modeling approaches, subgroup analyses, sensitivity analyses, and the secondary outcome of in-hospital mortality.

Conclusions: Obesity was associated with lower short-term and in-hospital mortality for ICU patients with a principal diagnosis of TBI. Studies exploring the mechanisms leading to these findings can improve understanding of the impacts of obesity on mortality following TBI.