GSBS Dissertations and Theses

Publication Date


Document Type

Master's Thesis

Academic Program

Master of Science in Clinical Investigation



First Thesis Advisor

Henna P. Santry, MD, MS


Aged, Comorbidity, Wounds and Injuries, Patient Discharge, Mortality, Trauma, Post-Injury Mortality


Theses, UMMS; Aged; Comorbidity; Wounds and Injuries; Patient Discharge; Mortality


Background: Traumatic injury remains a major cause of mortality in the US. Older Americans experience lower rates of injury and higher rates of death at lower injury severity than their younger counterparts. The objectives of this study were to explore pre-injury factors and injury patterns that are associated with post-discharge mortality among injured elderly surviving index hospitalization.

Methods: We queried a 5% random sample of Medicare beneficiaries (n=2,002,420) for any hospitalization with a primary ICD-9 diagnosis code for injury. Patients admitted without urgent/emergent admission were excluded, as well as patients presenting from inpatient hospitalization or rehabilitation. The primary endpoint was all-cause mortality. Patients were categorized into three mortality groups: death within 0-30 days, 31-90 days, or 91- 365 days post-discharge from the index hospitalization. These groups were compared with those who survived greater than one year post-discharge. Univariate tests of association and multivariable logistic regression models were utilized to identify factors associated with mortality during the 3 examined periods.

Results: 83,439 elderly patients (4.2%) were admitted with new injuries. 63,628 met inclusion criteria. 1,936 patients (3.0%) died during their index hospitalization, 2,410 (3.8%) died within 0-30 days, 3,084 (4.8%) died within 31-90 days, and 5,718 (9.0%) died within 91- 365 days after discharge. In multivariable adjusted models, advanced age, male sex, and higher Elixhauser score were associated with post-discharge mortality. The presence of critical injury had the greatest effect on mortality early after injury (0-30 days, OR 1.81, CI 1.64-2.00). Discharge to anywhere other than home without services was associated with an increased odds of dying.

Conclusions: Socio-demographic characteristics, disposition, and co-morbid factors were the strongest predictors of post-discharge mortality. Efforts to reduce injury-related mortality should focus on injury prevention and modification of co-morbidities.



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