Acute Kidney Injury in the Era of the AKI E-Alert

Abstract

Background and objectives: Our aim was to use a national electronic AKI alert to define the incidence and outcome of all episodes of community- and hospital-acquired adult AKI.

Design, setting, participants, & measurements: A prospective national cohort study was undertaken in a population of 3.06 million. Data were collected between March of 2015 and August of 2015. All patients with adult (≥18 years of age) AKI were identified to define the incidence and outcome of all episodes of community- and hospital-acquired AKI in adults. Mortality and renal outcomes were assessed at 90 days.

Results: There was a total of 31,601 alerts representing 17,689 incident episodes, giving an incidence of AKI of 577 per 100,000 population. Community-acquired AKI accounted for 49.3% of all incident episodes, and 42% occurred in the context of preexisting CKD (Chronic Kidney Disease Epidemiology Collaboration eGFR); 90-day mortality rate was 25.6%, and 23.7% of episodes progressed to a higher AKI stage than the stage associated with the alert. AKI electronic alert stage and peak AKI stage were associated with mortality, and mortality was significantly higher for hospital-acquired AKI compared with alerts generated in a community setting. Among patients who survived to 90 days after the AKI electronic alert, those who were not hospitalized had a lower rate of renal recovery and a greater likelihood of developing an eGFR<60 ml/min per 1.73 m2 for the first time, which may be indicative of development of de novo CKD.

Conclusions: The reported incidence of AKI is far greater than the previously reported incidence in studies reliant on clinical identification of adult AKI or hospital coding data. Although an electronic alert system is Information Technology driven and therefore, lacks intelligence and clinical context, these data can be used to identify deficiencies in care, guide the development of appropriate intervention strategies, and provide a baseline against which the effectiveness of these interventions may be measured.

Keywords: EGFR protein, human; Epidemiology and outcomes; Incidence; Intelligence; Prospective Studies; Receptor, Epidermal Growth Factor; Surveys and Questionnaires; acute kidney injury; acute renal failure; adult; clinical epidemiology; clinical nephrology; cohort studies; humans; kidney.

Copyright © 2016 by the American Society of Nephrology.

Figures

Figure 1.

Source of incident AKI electronic alerts (e-alerts). (A) Distribution of AKI stages for hospital-acquired AKI (HA-AKI) and community-acquired AKI (CA-AKI). (B) Percentage and number of nonprimary care (non-PC) patients with CA-AKI divided according to clinical specialty and AKI stage. Clinical specialty data were missing for 289 patients and excluded from analysis. (C) Percentage and number of patients with HA-AKI divided according to clinical specialty and AKI stage. Clinical specialty data were missing for 692 patients and excluded from analysis.

Figure 2.

Differing hospitalization rates for community-acquired AKI subsets. (A) Percentage, average age, and percentage with preexisting CKD (shaded area of each bar) in patients with primary care AKI (PC-AKI) who were hospitalized divided according to AKI stage (total number of patients: stage 1, 1531; stage 2, 255; and stage 3, 175). (B) Percentage, average age, and percentage with preexisting CKD (shaded area of each bar) in patients with nonprimary care AKI (non–PC-AKI) who were hospitalized divided according to AKI stage (total number of patients: stage 1, 3727; stage 2, 889; stage 3, and 542). PeCKD, preexisting CKD.

Figure 3.

Negative association between incidence of AKI and the index of social deprivation. Two hundred twenty-one patients with missing postcode data were excluded from analysis; 121 patients with English postcodes were excluded from analysis. WIMD, Welsh Index of Multiple Deprivation, where percentile 1 is the most deprived and percentile 100 is the least deprived.

Figure 4.

Differing ninety-day mortality rates associated with incident AKI electronic alerts for clinical location of AKI subsets. (A) Percentage of patients with AKI who died divided according to place of identification of AKI. (B) Percentage of patients with community-acquired AKI (CA-AKI) who died divided according to hospitalization. (C) Percentage of patients with CA-AKI who died divided according to place of identification of AKI. Mortality was significantly higher for all of the admitted groups (P<0.001 compared with nonadmitted groups). Mortality rates were comparable in the admitted nonprimary care CA-AKI and hospital-acquired AKI (HA-AKI) groups, which were significantly higher than in the primary care AKI (PC-AKI) admitted cohort (P<0.01). Numbers of patients with data available are indicated in parentheses on the x axis. Shading indicates the proportion of patients who died by AKI stage. Hosp. CA-AKI, hospitalized community–acquired AKI; non-hosp. CA-AKI, nonhospitalized community–acquired AKI; non–PC-AKI, nonprimary care AKI.

Figure 5.

Differing renal outcomes associated with AKI electronic alerts for clinical location of AKI subsets. (A) Renal outcome of patients with AKI divided according to place of identification of AKI. Of the patients for whom 90-day follow-up data were available, 1841 (1047, hospital-acquired AKI [HA-AKI]; 794, community-acquired AKI [CA-AKI]) had died within the 90-day follow-up period and were excluded from analysis. (B) Renal outcome of patients with CA-AKI divided according to place of identification of AKI. Of the patients for whom 90-day follow-up data were available, 794 (121, primary care–acquired AKI [PC-AKI]; 673, nonprimary care–acquired AKI [non–PC-AKI]) had died within the 90-day follow-up period and were excluded from analysis. Nonrecovery is expressed as a percentage of the whole cohort and was defined as achievement of a serum creatinine (SCr) value closest to and within 90 days still consistent with the definition of AKI in comparisons to baseline SCr values. (C) Renal outcome of patients with CA-AKI divided according to hospitalization. Of the patients for whom 90-day follow-up data were available, 794 (599, hospitalized community–acquired AKI [Hosp. CA-AKI]; 195, nonhospitalized community–acquired AKI [Non-hosp. CA-AKI]) had died within the 90-day follow-up period and were excluded from analysis.