Objective: To demonstrate prevalence, characteristics and outcomes of the elderly patients who were diagnosed with acute
kidney injury (AKI) in surgical intensive care units (ICUs).
Material and Method: AKI data were extracted from multicenter prospective cohort study conducted in 9 university-affiliated surgical ICUs in Thailand (THAI-SICU study) from April 2011 to January 2013. The elderly group was defined as those over 65 years old. Statistical analysis was done comparing baseline characteristics and outcomes between the elderly with AKI and those without.
Results: A total of 2,310 elderly patients (49.7%) were identified in our surgical ICUs from a total 4,652 cases. Of this elderly group, AKI was diagnosed in 445 cases (19.3%). The differences in the baseline characteristics of the elderly with AKI group were: older, higher number of males, greater number of smokers, and greater disease severity evaluated with APACHE-II
and SOFA score than the elderly without AKI. The ICU mortality and 28-day hospital mortality were higher in the elderly with
AKI than those without (28.1% vs. 5.2%, p<0.001 with RR = 5.401, 95% CI 4.231-6.895 and 35.7% vs. 9.4%, p<0.001 with
RR = 3.786, 95% CI 3.138-4.569, respectively). Using multivariable logistic regression analysis and after adjustment of
covariates, independent potential risk factors of developing AKI in the SICU included: older age, higher APACHE-II and SOFA score, smoking history, emergency surgery, concurrent sepsis, cardiac complications, delirium, and requiring respiratory
support during ICU stay.
Conclusion: Geriatric patients made up almost half of our surgical ICU population and nearly one-fifth of them suffered AKI. Once they had AKI, ICU mortality and 28-day hospital mortality were higher than those without AKI.

Keywords: Acute kidney injury, Elderly patient, Surgical intensive care unit, Risk factors, Intensive care unit mortality