ICU Readmission in Injured Older Adults: Modifiable Risk Factors and Implications.

BACKGROUND: Prior evaluations of ICU readmission among injured older adults have inconsistently identified risk factors, with findings limited by use of sub-analyses and small sample sizes. This study aimed to identify risk factors for and implications of ICU readmission in injured older adults. METHODS: This retrospective, single-center cohort study was conducted at a High-Volume Level 1 Trauma Center and included injured older adult patients (>65 years old) requiring at least one ICU admission during hospitalization between 2013-2018. Patients who died <48 hours of admission were excluded. Exposures included patient demographics and clinical factors. The primary outcome was ICU readmission. Multi-variable regression was used to identify risk factors for ICU readmission. RESULTS: 6,691 injured adult trauma patients were admitted from 2013-2018, 55.4% (n = 3,709) of whom were admitted to the ICU after excluding early deaths. Of this cohort, 9.1% (n = 339) were readmitted to the ICU during hospitalization. Readmitted ICU patients had a higher median Injury Severity Score (21 (IQR: 14-26) vs 16 (IQR: 10-24)), with similar mechanisms of injury between the two groups. Readmitted ICU patients had a significantly higher mortality (19.5%) compared to single ICU admission patients (9.9%) (p < 0.001) and higher rates of developing any complication, including delirium (61% vs 30%, p < 0.001). On multivariable analysis, the factors associated with the highest risk of readmission were delirium (RR = 2.6, 95% CI 2.07 - 3.26) and aspiration (RR = 3.04, 95% CI 1.67- 5.54). More patients in the single ICU admission cohort received comfort-focused care at the time of their death as compared to the ICU readmission cohort (93% vs 85%, p = 0.035). CONCLUSIONS: Readmission to the ICU is strongly associated with higher mortality for injured older adults. Efforts targeted at preventing respiratory complications and delirium in the geriatric trauma population may decrease the rates of ICU readmission and related mortality risk. LEVEL OF EVIDENCE: III/Epidemiologic.