Pelvic fractures in severely injured elderly: a double-adjustment propensity score matched analysis from a level I trauma center

PURPOSE: Pelvic trauma has increased risk of mortality in the elderly. Our study aimed to analyze the impact of the additional burden of pelvic fractures in severely injured elderly. METHODS: This is a retrospective analysis of a prospectively maintained trauma registry from 2012 to 2018 at an American College of Surgeons (ACS) verified Level I Trauma Center. Trauma patients aged ≥ 65 years with ISS ≥ 16 and AIS severity score ≥ 3 in at least two body regions were divided in two groups: group I, consisted of elderly polytrauma patients without pelvic fractures, and group II elderly who had concomitant pelvic fractures. We used a double-adjustment method using propensity score matching (PSM) with subsequent covariate adjustment to minimize the effect of confounding factors, and give unbiased estimation of the impact of pelvic fractures. Balance assessment was conducted by computing absolute standardized mean differences (ASMDs) and ASMD < 0.10 reflects good balance between groups. RESULTS: Of 12,774 patients admitted during this time, 411 (3.2%) elderly with a mean age of 77.75 ± 8.32 years met the inclusion criteria. Of this cohort, only 92 patients (22.4%) had pelvic fractures. Females outnumbered males (55 vs. 45%). Comparing characteristics of group I and group II using ASMDs, pelvic trauma patients were more likely to have higher systolic blood pressure (SBP), head injuries, lower extremity injuries, anticoagulant therapy, and cirrhosis. Fewer variables differed significantly after matching. We observed few instances of worse outcomes associated with pelvic trauma using PSM with and without covariate adjustment. Crude PSM without covariate adjustment, showed a significantly higher rate of deep vein thrombosis (DVT) for pelvic trauma (p < 0.001). Crude PSM also showed a significantly higher rate of ventilator-associated pneumonia (VAP) in group II (p = 0.006). PSM with covariate adjustment did not confirm differences on these outcomes. PSM both without and with covariate adjustment found lower ventilator days and ICU length of stay among patients with pelvic trauma. No significant differences were seen on 12 outcomes: death, acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), cardiac arrest with cardiopulmonary resuscitation (CPR), myocardial infarction (MI), pulmonary embolism (PE), unplanned intubation, unplanned admission to intensive care unit (ICU), catheter-associated urinary tract infection (CAUTI), and hospital length of stay. CONCLUSIONS: At a Level I Trauma Center the additional burden of pelvic fractures in seriously injured elderly did not translate into higher mortality. PSM without covariate adjustment suggests worse rates among pelvic trauma patients for DVT and VAP but covariate adjustment removed statistical significance for both outcomes. Pelvic trauma patients had shorter time on ventilator and in the ICU. Whether similar analytic methods applied to patients from larger data sources would produce similar findings remains to be seen.