Historically, the study outcomes for obesity (BMI >30) as a risk factor in trauma and post-traumatic surgery outcomes offer either a perplexing heterogeneity or a lack of necessary detail. A leading study from the 1990s, for example, concluded that of all preexisting conditions, obesity alone failed to confer worse outcomes after trauma. Subsequent studies found both increased risk of complications and mortality, and protective effects for obesity in trauma. While largely unexplored, the few studies of obesity as a risk factor for trauma surgery have been similarly confounding.
Because addressing the needs of all patient populations is a core mission for trauma centers, and because the prevalence of obesity continues to rise in the United States, definitive answers to these issues are imperative. Thus, to address these concerns, a team of investigators led by Surgery Fellow Elinore Kaufman, MD, recently performed a pair of studies at Penn Medicine and the Perelman School of Medicine. Their findings appeared in the Journal of Surgical Research.
Obesity as a Risk for Mortality After Trauma
To assess the risk of in-hospital mortality for obese patients in the wake of trauma, the Penn team conducted a retrospective cohort study using state-wide Pennsylvania Trauma Outcomes Study (PTOS) registry information, and in a complete case analysis for 46,329 patients, found obesity significantly associated with mortality. Among the factors assessed were injury mechanism, presence of complication, age, sex, need for blood transfusion, Revised Trauma Score, and Injury Severity Score. In addition to increased mortality risk, certain complications, including respiratory, thromboembolic and infectious events, were more common in obese patients than their normal weight counterparts.
Obesity as a Risk for Complications in Trauma Surgery
In a separate study, the team analyzed trauma registry information at all 30 level I and II Pennsylvania trauma centers between 2011-2014, and after controlling for other co-morbidities, discovered that by comparison to non-obese patients, obese patients undergoing abdominal surgery for trauma were more likely to develop complications — particularly pneumonia, sepsis and deep vein thrombosis — but were no more likely to die after a complication, suggesting that the ability of trauma centers to manage complications is not impaired in obese patients.
Caring for the Obese in Surgery
Both studies considered the unmet needs of the obese population, noting that the apparent greater risk of complications in the obese brings to the foreground the fact that present processes of care are not attuned to the needs of this population, and the potential influence of provider and systemic bias (for more on this topic, see the Penn Physician Blog article In-Office Updates from the Penn Metabolic and Bariatric Surgery Program: What Community Physicians Need to Know).