Objective: We aimed to investigate the hypothesis that identical abbreviated injury scale (AIS) scores may lead to varying risks of in-hospital mortality and admission to the intensive care unit (ICU) depending on the specific body region affected. Methods: This study focused on hospitalized trauma patients with moderate to serious injuries (AIS=2, 3). The final sample was stratified based on the injured body regions. To determine the impact of these injuries on mortality and ICU admission, we conducted binary logistic regression after adjusting for confounding factors. Results: Overall, 16,040 trauma patients with moderate injury (AIS=2) and 1,338 trauma patients with serious injury (AIS=3) were included in this study. When comparing outcome of trauma patients in different body region, there was no significant difference in the odds of two main outcomes in various injury sites, except for extremities (P values>0.05). When the AIS=2 patients were controlled for confounding factors, the adjusted odds of mortality were significantly higher for head, face, and neck injuries, as well as spine/back, thoracic, and abdominal injuries, compared to extremity injuries (adjusted odds ratio (aOR)s=9.81,8.78, 8.11, and 3.96, respectively; P-values<0.05). Among those with AIS=3, the odds of mortality were significantly greater for abdominal (aOR=7.05, P-value=0.009) and head, face, and neck injuries (aOR=2.73, P-value=0.001) than for extremity injuries. Conclusion: Injuries with the same AIS (=2, 3) value almost indistinguishably confer the same mortality risk and ICU admission, except for extremities. The unique AIS value assigned to various body sites almost consistently indicate the same likelihood of negative outcomes.