CLINICAL OUTCOMES OF PATIENTS WITH ACUTE KIDNEY INJURY ON CHRONIC KIDNEY DISEASE: IMPACT OF AGE, RACE AND GENDER

Background: Acute kidney injury (AKI) in hospitalized patients is linked to adverse outcomes. Presence of chronic kidney disease (CKD) in these patients has been shown to be an independent risk factor. Outcomes of patients with AKI on CKD have not been well-examined. This study is a retrospective analysis of outcomes in hospitalized patients with AKI on CKD.

Methods: Vizient database is a large administrative database and was queried with ICD-10 codes for acute renal failure as principal diagnosis. A secondary diagnosis of CKD was used to identify patients with AKI on CKD. Outcome variables analyzed included mortality, direct costs, length of stay and ICU admission. Impact of age, gender and race was also examined.

Results: 88,921 patients were noted to have AKI but no CKD. 87,722 patients were found to have AKI on CKD during the study period. Patients with AKI on CKD showed significantly higher length of stay (5.19 days in AKI but no CKD vs. 5.56 days in AKI on CKD; p<0.0001) and slightly higher but not significantly different costs and mortality (2.16% in AKI but no CKD vs 2.39% in AKI on CKD). Patient with AKI on CKD were then examined for gender disparities. Only ICU admission was found to be significantly different (10.52% in male vs 9.61% in female; p<0.0001). Length of stay, costs and ICU admission were not different with respect to gender. With respect to age, length of stay (5.27 ± 6.65 days in 18-50 years vs 5.65 ± 6.12 days in 51-74 years age; p<0.0001) and costs ($ 6234 in 51-74 years vs $ 5239 in >75 years; p<0.0001) were highest in the 51-74 years age group. Mortality was highest in >75 years age groups compared to younger age (0.87% in 18-50 years vs 3.38% in >75 years; p<0.0001). With respect to race, ICU admission and length of stay was not significantly different between racial groups. Mortality was significantly different and was higher in Caucasians (2.07% in Asians vs 2.72% in Caucasians; p<0.0001). Costs were highest in Asians ($ 6383).

Conclusions: Results from this study showed relatively worse outcomes in patients with AKI on CKD compared to patients with AKI but no CKD. In patients with AKI on CKD, few gender and racial differences were noted in outcomes. Mortality was higher in older age groups but length of stay and costs were highest in the 51-74 years age group.