Body-Mass-Index > 35 as an Independent Predictor of Mortality in Severe Traumatic Brain Injury

OBJECTIVE: Severe Traumatic Brain Injury (TBI) has a major influence on polytrauma outcome. Aim of this study was to evaluate the impact of Body Mass Index (BMI) on mortality and early neurological outcome in patients suffering from severe TBI with a special focus on obesity class II and III (BMI ≥ 35).

METHODS: A retrospective cohort analysis of patients suffering from a leading, at least severe TBI and registered in the TraumaRegister DGU(®) was conducted. Patients alive on admission with full status documentation on Glasgow Coma Scale (GCS), height and weight were classified into 4 BMI subgroups. Early neurological outcome was classified using the Glasgow Outcome Scale (GOS).

RESULTS: A total of 1,634 patients met the inclusion criteria. Lowest mortality was documented for BMI group 1 (15.2%, BMI 25.0-29.9918.5), highest mortality was found in BMI group 5 (25.6%, BMI ≥ 35). BMI ≥ 35 was an independent predictor of mortality with an Odds ratio (OR) of 3.15 (95% confidence interval (CI) [1.06-9.36]), p=0.039). Further independent mortality predictors were > 65 years of age, a GCS of 13 or less, an Abbreviated Injury Scalehead ≥5, prehospital cardiopulmonary resuscitation and a prehospital blood pressure of <90mmHg. In terms of good early neurological no differences were recorded between the BMI groups (range 59.0%-62.6%, p=0.087).

CONCLUSIONS: In this study a BMI ≥ 35 is an independent predictor of mortality and is associated with an inferior early functional neurological outcome.