(Gleaned from the 2018 USRDS Annual Data Report: Volume 1, Chapter 5: www.usrds.org)

Acute kidney injury (AKI), also called acute renal failure, is a rapid loss of kidney function. It is a common complication among hospitalized patients and is associated with both morbidity and mortality. 

Among survivors of AKI, AKI is recognized as a major risk factor for the development of chronic kidney disease (CKD). Studies have demonstrated a significantly increased long-term risk of CKD and ESRD following AKI, even after kidney function recovers initially. Furthermore, this relationship is bidirectional — CKD patients are at substantially higher risk for AKI. As a result, AKI is frequently superimposed on CKD and can contribute significantly to the progression of CKD.

Highlights of the Report:

• In 2016, 4.4% of Medicare fee-for-service beneficiaries experienced a hospitalization complicated by AKI, double that (2.2%) in 2006.
• Age is a major risk factor for AKI. It also increases in the presence of comorbidities such as chronic kidney disease (CKD) and diabetes mellitus (DM). About 1 in 5 hospitalized Medicare patients with both CKD and DM experience a hospitalization with AKI each year.
• Among hospitalized veterans age 22 and up, 25.4% met the guidelines for AKI. This included 21.4%, 0.8%, and 3.2% of patients with Stage 1, Stage 2, and Stage 3 AKI. Just over half (52.6%) of patients who met the criteria for AKI were diagnosed with AKI.
• In 2014, Medicare patients age 66 and up who were hospitalized for AKI had a 36% cumulative probability of a recurrent AKI hospitalization within one year.
• Among Medicare patients without a pre-existing diagnosis of CKD, 30.8% were given a new diagnosis of CKD in the year following an AKI hospitalization. Among Medicare patients with a “new” diagnosis of CKD in 2016, 25% had an AKI hospitalization in the preceding year.
• Among Medicare patients age 66 and up with a first AKI hospitalization in 2016, the in-hospital mortality rate was 8.2%, or 13.2% when including discharge to hospice. Comparable mortality rates for non-AKI hospitalizations were 1.8% and 3.8%. Less than half of all patients returned to their home on discharge, as compared to two-thirds of non-AKI patients, while 30.1% were discharged to an institution such as rehabilitation or skilled nursing facilities.