The impact of anemia on renal recovery and survival in acute kidney injury

Background: Anemia occurs frequently among patients who develop acute kidney injury likely due to abnormal erythropoietic activity. Anemia has been associated with increased mortality among hospitalized patients, but its impact on renal recovery or survival is poorly characterized among patients with acute kidney injury. We aim to assess if anemia is associated with lower renal recovery and poorer survival. Methods: A retrospective cohort of 211 patients was examined. Anemia and other patient characteristics were assessed as potential risk factors for the presence of renal recovery or death. Additionally, renal recovery, dialysis requirement and survival were compared between those with mild versus severe anemia. Results: 86% of patients with acute kidney injury (AKI) developed acute anemia which generally occurred at the time of acute kidney injury. Anemia did not appear to be associated with lack of renal recovery or death, but rather underlying comorbid conditions and severity of illness were more likely to be associated with renal recovery or death, respectively. Neither renal recovery nor survival differed among patients with mild versus severe anemia as measured by fall in hemoglobin or nadir hemoglobin. Conclusions: New onset anemia does not appear to be associated with lack of renal recovery or death among patients with acute kidney injury.