Association Between Level of Arousal and 30-Day Survival in Acutely Ill Older Adults.

Objective: To investigate the association between impaired arousal on admission and 30-day mortality in acutely ill older adults.

Design: Retrospective cohort study.

Setting And Participants: Patients age +65 years admitted to the geriatric ward of a tertiary university hospital from 2010 to 2018 in Sao Paulo, Brazil.

Methods: Participants were evaluated on admission according to a standardized comprehensive geriatric assessment model. Delirium was detected using the short version of the Confusion Assessment Method (Short-CAM). We used 2 alternative criteria to define impaired arousal: lethargy, stupor, or coma according to the Short-CAM; and a Glasgow Coma Scale (GCS) score of ≤13. Our primary outcome was time-to-death in 30 days, and we used Cox proportional hazards models to explore the association between impaired arousal and decreased survival.

Results: We included 1554 admissions with a mean age of 81 years and of whom 61% were women. Overall, prevalent delirium was observed in 28% of the cases. We found that in 33% of admissions, patients were lethargic, stuporous, or comatose, and that in 23%, they had GCS scores of ≤13. General 30-day mortality was 19% but reached 32% in patients with GCS scores of ≤13. Impaired arousal was independently associated with lower survival in 30 days, both when defined using Short-CAM criteria [lethargy + stupor + coma: hazard ratio (HR) 2.33, 95% confidence interval (CI) 1.66‒3.27] and GCS scores (GCS 12‒13: HR 1.62, 95% CI 1.13‒2.33; GCS ≤ 11: HR 2.53, 95% CI 1.68‒3.80). In interaction analyses, we confirmed our results in patients who had impaired arousal but were neither delirious (lethargy + stupor + coma: HR 2.16, 95% CI 1.44‒3.24; GCS ≤ 11: HR 3.07; 95% CI 1.50‒6.29) nor demented (lethargy + stupor + coma: HR 1.95, 95% CI 1.15‒3.28).

Conclusions And Implications: Level of arousal on admission was an independent predictor of 30-day survival in acutely ill older adults, regardless of delirium or baseline dementia. Clinicians should be aware that even if unsure of whether a patient has delirium, arousal assessment can provide crucial clinical and prognostic insight.