In-hospital complications in trauma patients are frequent and associated with 
increased morbidity and mortality. The aim of this study was to analyze the 
association between posttraumatic complications and the injured body region, 
injury and trauma severity, length of stay, and mortality in hospitalized trauma 
patients. This observational and retrospective study included 147 trauma 
patients with posttraumatic complications hospitalized in a university hospital 
located in São Paulo, Brazil. The injury and trauma severity was measured using 
the Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS), 
respectively. The association between variables was verified applying χ test, 
Fisher exact text, likelihood ratio, and Mann-Whitney U test, considering 
significance level of 5%. The most frequent in-hospital complications were 
infectious, cardiovascular, metabolic, and renal. Patients with head injury AIS 
score of 3 or more had higher percentage of neurological complications and those 
with lower extremity injury AIS score of less than 3 had higher percentage of 
metabolic and renal complications. There was no association between thoracic 
injury and cardiovascular complications, nor between types of complications and 
trauma severity (ISS). Patients without cardiovascular complication and those 
with infections had longer hospital length of stay, and mortality was higher in 
those with cardiovascular complications. Complication's studies in trauma 
patients may contribute to identify events related with poor outcome and to 
implement specific measures for improving quality of trauma care and patient 
security.