It Is About Time: Extinguishing the Fire of Acute Kidney Injury

Development and validation of an interpretable clinical score for early identification of acute kidney injury at the emergency department

Acute kidney injury (AKI) in hospitalised patients is a common syndrome associated with poorer patient outcomes. Clinical risk scores can be used for the early identification of patients at risk of AKI. We conducted a retrospective study using electronic health records of Singapore General Hospital emergency department patients who were admitted from 2008 to 2016. The primary outcome was inpatient AKI of any stage within 7 days of admission based on the Kidney Disease Improving Global Outcome (KDIGO) 2012 guidelines. A machine learning-based framework AutoScore was used to generate clinical scores from the study sample which was randomly divided into training, validation and testing cohorts. Model performance was evaluated using area under the curve (AUC). Among the 119,468 admissions, 10,693 (9.0%) developed AKI. 8491 were stage 1 (79.4%), 906 stage 2 (8.5%) and 1296 stage 3 (12.1%). The AKI Risk Score (AKI-RiSc) was a summation of the integer scores of 6 variables: serum creatinine, serum bicarbonate, pulse, systolic blood pressure, diastolic blood pressure, and age. AUC of AKI-RiSc was 0.730 (95% CI 0.714–0.747), outperforming an existing AKI Prediction Score model which achieved AUC of 0.665 (95% CI 0.646–0.679) on the testing cohort. At a cut-off of 4 points, AKI-RiSc had a sensitivity of 82.6% and specificity of 46.7%. AKI-RiSc is a simple clinical score that can be easily implemented on the ground for early identification of AKI and potentially be applied in international settings.

Review of the Literature on the Costs Associated With Acute Kidney Injury

Acute kidney injury (AKI) develops in 8% to 16% of hospital admissions. These patients exhibit a 4- to 10-fold increase in mortality and prolonged hospital stays. There is a dearth of information on the economics of AKI, especially in critically ill patients whose health-care costs are already high. It is important that pharmacists understand the economic impact of AKI to optimally prevent and treat AKI occurrence, thus reducing total hospital costs. Authors used MEDLINE, PubMed, and Google Scholar searches up to April 2019. Inpatient AKI affects an estimated 498 000 patients in the United States with its annual cost from $4.7 to $24.0 billion. Average patient costs of AKI in the intensive care unit are generally double than those of non-AKI patients. High AKI severity portends a higher cost. Total hospital costs in patients with AKI ranged from $29 700 in cardiac surgery patients to $80 400 in cardiogenic shock. Incremental increases of cost range from $9400 in major surgery patients and up to $81 000 in nonsurviving dialysis patients. The enormity of the clinical and economic impact of AKI should be a call to action by pharmacists to expeditiously select patient-specific therapies to prevent and treat AKI, and thus reduce its economic burden on an already fragile health-care system.