Interaction of Obese Body Mass Index and Comorbidities on Inflammatory Profiles and Clinical Outcomes After Traumatic...

Obesity has been associated with worse clinical outcomes after mild traumatic brain injury (mTBI; Glasgow Coma Scale score between 13 and 15). Augmented inflammatory response to mTBI appears to be an important modifier of outcomes for the patients with obesity, but the contribution of comorbidity profile has yet to be analyzed. The objective of this study was to examine the association of: 1. comorbidity profile; and 2. the interaction of obesity with comorbidity profile on clinical outcomes and inflammatory blood biomarkers after mTBI.

Participants were enrolled across emergency departments within 24 h of injury, with clinical outcomes and neurocognitive tests assessed at 2 weeks and 6 months post-injury (n = 1337). Latent class analysis (LCA) was used to identify comorbidity profiles and mixed-effect models for the association of obesity and comorbidity profile on inflammatory/clinical outcomes.

Using LCA, 3 classes of comorbidities were identified: "cardiovascular" (high rates of cardiovascular disease, hypertension, hyperlipidemia, diabetes; n = 287; 21%), "internalizing" (high rates of depression/anxiety, n = 121; 9%), and "healthy" (0%-8% rate of comorbidities; n = 929; 69%). "Healthy" had higher rates of functional recovery at 6 month (31%; p = 0.001) than "cardiovascular" and "internalizing" (15%-26%). Within "healthy," obesity was associated with higher c-reactive protein levels on day 1 (ratio = 1.86; p < 0.001), 2 week (ratio = 2.05; p < 0.001) and 6 month (ratio = 2.34; p < 0.001) relative to normal BMI. Obesity was associated with higher IL-6 levels at 2 week (ratio = 1.36; p = 0.005) and 6 month (ratio = 1.47; p < 0.001) relative to normal BMI within "healthy."

Obesity and comorbidity profiles are associated with an inflammatory response with the potential to impact recovery; consideration of systemic health at the time of injury could improve recovery.