Under-detection of acute kidney injury in hospitalised patients: a retrospective, multi-site, longitudinal study

Acute kidney injury predicts the risk of adverse cardio renal events and all cause death in southeast Asian people with type 2 diabetes

Patients with diabetes are susceptible to acute kidney injury (AKI) as compared to counterparts without diabetes. However, data on the long-term clinical outcome of AKI specifically in people with diabetes are still scarce. We sought to study risk factors for and adverse cardio-renal outcomes of AKI in multi-ethnic Southeast Asian people with type 2 diabetes. 1684 participants with type 2 diabetes from a regional hospital were followed an average of 4.2 (SD 2.0) years. Risks for end stage kidney disease (ESKD), major adverse cardiovascular events (MACE) and all-cause death after AKI were assessed by survival analyses. 219 participants experienced at least one AKI episode. Age, cardiovascular disease history, minor ethnicity, diuretics usage, HbA1c, baseline eGFR and albuminuria independently predicted risk for AKI with good discrimination. Compared to those without AKI, participants with any AKI episode had a significantly high risk for ESKD, MACE and all-cause death after adjustment for multiple risk factors including baseline eGFR and albuminuria. Even AKI defined by a mild serum creatinine elevation (0.3 mg/dL) was independently associated with a significantly high risk for premature death. Therefore, individuals with diabetes and any episode of AKI deserve intensive surveillance for cardio-renal dysfunction.

Clinical characteristics and outcomes of community acquired-acute kidney injury

PURPOSE

Published works have reported the impact of a nephrologist intervention on outcomes for patients with hospital-acquired acute kidney injury (HA-AKI), however little is known about the clinical characteristics of patients with community-acquired acute kidney injury (CA-AKI) and the impact of nephrology interventions on outcomes in these patients.

METHODS

A retrospective study on all adult patients admitted to a large tertiary care hospital in 2019 who were identified to have CA-AKI were followed from hospital admission to discharge. Clinical characteristics and outcomes of these patients were analysed by receipt of nephrology consultation. Statistical analysis included descriptive, simple Chi-squared/Fischer Exact test, independent samples t-test/Mann-Whitney U test and logistic regression.

RESULTS

182 patients fulfilled the study inclusion criteria. Mean age was 75 ± 14 years, 41% were female, 64% had stage 1 AKI on admission, 35% received nephrology input and 52% had achieved recovery of kidney function by discharge. Higher admission and discharge serum creatinine (SCr) (290.5 vs 159 and 173 vs 109 µmol/L respectively, p =  < 0.001), and younger age (68 vs 79, p =  < 0.001) were associated with nephrology consultations, whilst length of hospitalisation, mortality and rehospitalisation rates were not significantly different between the two groups. At least 65% were recorded to be on at least one nephrotoxic medication.

CONCLUSION

Our findings provide a snapshot of current practice where close to two-thirds of hospitalised patients with CA-AKI had a mild form of AKI that was associated with good clinical outcomes. While higher SCr on admission and younger age were predictors of receiving a nephrology consultation, nephrology consultations did not have any impact on outcomes.

Medication use and hospital-acquired acute kidney injury: an electronic health record-based study

BACKGROUND AND AIMS

Medications remain an important contributor to the development of acute kidney injury (AKI). This study aimed to examine associations between (i) administration of medications known to reduce glomerular filtration rate (GFR), that is, GFR modifiers and subsequent hospital-acquired AKI; and (ii) potentially medication-related AKI and patient adverse outcomes.

METHODS

A retrospective cohort study utilising electronic health record data of patients admitted to a tertiary hospital in Australia in 2015. Timing of medication administration was compared with timing of AKI development. AKI cases were identified using an algorithm based on serum creatinine level changes. Multilevel regression models were applied with adjustment for relevant demographic and clinical factors.

RESULTS

Among 11 503 admissions, AKI was identified in 955 patients (8.3%) and 637 (66.7% of 955) were preceded by administration of a GFR modifier. Patients without prior AKI were 17% more likely to develop AKI after administration of these medications (adjusted odds ratio 1.17, 95% confidence interval (CI) 1.003-1.37). Older age and comorbidity with diabetes, acute myocardial infarction, peripheral vascular disease, liver cirrhosis and multiple myeloma were also significant predictors. Patients with potentially medication-related AKI were 11.69 times more likely to die in hospital (95% CI 7.84-17.43) and stayed 3.49 times longer in hospital (95% CI 3.26-3.73), compared with those without AKI.

CONCLUSIONS

Administration of medications contributing to the reduction of GFR is associated with an increased risk of hospital-acquired AKI and worse patient outcomes. Caution is required when prescribing these medications to patients at risk of developing AKI, and monitoring patients for deterioration is needed if administered.

Electronic alerts and a care bundle for acute kidney injury-an Australian cohort study

BACKGROUND

Early recognition of hospital-acquired acute kidney injury (AKI) may improve patient management and outcomes.

METHODS

This multicentre study was conducted at three hospitals (H1-intervention; H2 and H3-controls) served by a single laboratory. The intervention bundle [an interruptive automated alerts (aAlerts) showing AKI stage and baseline creatinine in the eMR, a management guide and junior medical staff education] was implemented only at H1. Outcome variables included length-of-stay (LOS), all-cause in-hospital mortality and management quality.

RESULTS

Over 6 months, 639 patients developed AKI (265 at H1 and 374 at controls), with 94.7% in general wards; 537 (84%) patients developed Stage 1, 58 (9%) Stage 2 and 43 (7%) Stage 3 AKI. Median LOS was 9 days (IQR 4-17) and was not different between intervention and controls. However, patients with AKI stage 1 had shorter LOS at H1 [median 8 versus 10 days (P = 0.021)]. Serum creatinine had risen prior to admission in most patients. Documentation of AKI was better in H1 (94.8% versus 83.4%; P = 0.001), with higher rates of nephrology consultation (25% versus 19%; P = 0.04) and cessation of nephrotoxins (25.3 versus 18.8%; P = 0.045). There was no difference in mortality between H1 versus controls (11.7% versus 13.0%; P = 0.71).

CONCLUSIONS

Most hospitalized patients developed Stage 1 AKI and developed AKI in the community and remained outside the intensive care unit (ICU). The AKI eAlert bundle reduced LOS in most patients with AKI and increased AKI documentation, nephrology consultation rate and cessation of nephrotoxic medications.

Definitions, phenotypes, and subphenotypes in acute kidney injury-Moving towards precision medicine

The current definition of acute kidney injury (AKI) is generic and, based only on markers of function, is unsuitable for guiding individualized treatment. AKI is a complex syndrome with multiple presentations and causes. Targeted AKI management will only be possible if different phenotypes and subphenotypes of AKI are recognised, based on causation and related pathophysiology. Molecular signatures to identify subphenotypes are being recognised, as specific biomarkers reveal activated pathways. Assessment of individual clinical risk needs wider dissemination to allow identification of patients at high risk of AKI. New and more timely markers for glomerular filtration rate (GFR) are available. However, AKI diagnosis and classification should not be limited to GFR, but include tubular function and damage. Combining damage and stress biomarkers with functional markers enhances risk prediction, and identifies a population enriched for clinical trials targeting AKI. We review novel developments and aim to encourage implementation of these new techniques into clinical practice as a strategy for individualizing AKI treatment akin to a precision medicine-based approach.

Acute kidney injury increases risk of kidney stones-a retrospective propensity score matched cohort study

BACKGROUND

Acute kidney injury (AKI) is common. An episode of AKI may modify the risk of developing kidney stones by potential long-term effects on urine composition. We aimed to investigate the association between AKI and the risk of kidney stone presentations.

METHODS

The retrospective cohort study used patient data (1 January 2008-31 December 2017), from an Australian Local Health District, which included AKI diagnosis, demographics, comorbidities and kidney stone admissions. Time-varying Cox proportional hazards and propensity-matched analysis were used to determine the impact of AKI on the risk of kidney stones. To address possible population inhomogeneity in comparisons between no AKI and hospitalized AKI, sub-group analysis was done comparing inpatient and outpatient AKI versus no AKI, to assess consistency of association with future stones. Sensitivity analysis was undertaken to capture the impact of a known AKI status and AKI severity.

RESULTS

Out of 137 635 patients, 23 001 (17%) had an AKI diagnosis and 2295 (2%) had kidney stone presentations. In the unadjusted analysis, AKI was associated with kidney stones, with AKI used as a time-varying exposure, [hazard ratio (HR) 1.32, 95% confidence interval (CI) 1.16-1.50)]. Both inpatient-AKI (HR 1.19, 95% CI 1.01-1.39) and outpatient-AKI (HR 1.59, 95% CI 1.30-1.94) were significantly associated with future stones compared to no AKI subjects. This association persisted in the adjusted analysis (HR 1.45, 95% CI 1.26-1.66), propensity-matched dataset (HR 1.67, 95% CI 1.40-1.99) and sensitivity analysis. There was a dose-response relationship with higher stages of AKI being associated with a greater risk of kidney stones.

CONCLUSIONS

In a large cohort of patients, AKI is associated with a greater risk of kidney stones, which increases with higher stages of AKI. This association should be examined in other cohorts and populations for verification.

Impact of decreasing vancomycin exposure on acute kidney injury in stem cell transplant recipients

OBJECTIVE

To evaluate the change in vancomycin days of therapy (DOT) and vancomycin-associated acute kidney injury (AKI) after an antimicrobial stewardship program (ASP) intervention to decrease vancomycin use in stable patients after hematopoietic stem cell transplantation (HSCT).

DESIGN

Retrospective cohort study and quasi-experimental interrupted time series analysis. Change in unit-level vancomycin DOT per 1,000 inpatient days after the intervention was assessed using segmented Poisson regression. Subject-specific risk of vancomycin-associated AKI was evaluated using a random intercept logistic regression model with mediation analysis.

SETTING

HSCT unit at a single quaternary-care pediatric hospital.

PARTICIPANTS

Inpatients aged 3 months and older who underwent HSCT between January 1, 2015, and March 31, 2019 (27 months before and after the intervention) who received any dose of vancomycin.

INTERVENTION

An ASP intervention in April 2017 creating a new practice guideline to decrease prolonged (>72 hours) vancomycin courses for stable HSCT patients with febrile neutropenia.

RESULTS

Overall, 439 vancomycin exposures (234 before the intervention and 205 after the intervention) occurring across 300 transplants and 259 subjects were included. The mean vancomycin DOT was 307 per 1,000 inpatient days (95% confidence interval [CI], 272-342) and decreased after the intervention to 207 per 1,000 inpatient days (95% CI, 173-240). In multivariable analyses, the odds of AKI in the postintervention period were 37% lower than in the preintervention period (adjusted OR, 0.63; 95% CI, 0.42-0.95; P = .0268); 56% of the excess risk was mediated by vancomycin DOT.

CONCLUSIONS

An ASP intervention successfully decreased vancomycin use after HSCT and resulted in a decrease in AKI. Reducing empiric antibiotic exposure for stable patients after HSCT can improve clinical outcomes.

The kinetic estimated glomerular filtration rate ratio predicts acute kidney injury

AIM

Kinetic estimated Glomerular Filtration Rate (KeGFR) approximates GFR under non-steady-state conditions. We investigated whether the ratio of KeGFR difference to baseline eGFR could predict acute kidney injury (AKI) earlier than a creatinine-based algorithm that triggered an AKI electronic Alert (eAlert).

METHODS

This retrospective, single-centre, proof-of-concept cohort study assessed all patients diagnosed with AKI by an automated serum creatinine-based eAlert. The kinetic eGFR, the kinetic eGFR difference from baseline and the ratio of difference to baseline was calculated in subjects with at least two serum creatinine (sCr) measurements within 72 h of AKI.

RESULTS

Patients in the AKI cohort (n = 140) had a significant decline in KeGFR ratio (AKI: 17% IQR 7% to 29%, Non-AKI: 0 IQR -12% to 9%; P-value <.0001). A decrease of the ratio greater than 10% predicted AKI with a sensitivity of 66%, a specificity of 77%, a positive predictive value of 63%, and negative predictive value of 80%. The median lead time between KeGFR ratio decrease and AKI was 24 h (IQR: 19-27 h).

CONCLUSIONS

KeGFR ratio is a cheap, simple method that predicted AKI 24 h before laboratory detection. KeGFR may facilitate triaging patients to increased monitoring or intervention.

Diagnostic Informatics-The Role of Digital Health in Diagnostic Stewardship and the Achievement of Excellence, Safety, and Value

Diagnostic investigations (pathology laboratory and medical imaging) aim to: increase certainty of the presence or absence of disease by supporting the process of differential diagnosis; support clinical management; and monitor a patient's trajectory (e. g., disease progression or response to treatment). Digital health can be defined as the collection, storage, retrieval, transmission, and utilization of data, information, and knowledge to support healthcare. Digital health has become an essential component of the diagnostic process, helping to facilitate the accuracy and timeliness of information transfer and enhance the effectiveness of decision-making processes. Digital health is also important to diagnostic stewardship, which involves coordinated guidance and interventions to ensure the appropriate utilization of diagnostic tests for therapeutic decision-making. Diagnostic stewardship and informatics are thus important in efforts to establish shared decision-making. This is because they contribute to the establishment of shared information platforms (enabling patients to read, comment on, and share in decisions about their care) based on timely and meaningful communication. This paper will outline key diagnostic informatics and stewardship initiatives across three interrelated fields: (1) diagnostic error and the establishment of outcomes-based diagnostic research; (2) the safety and effectiveness of test result management and follow-up; and (3) digitally enhanced decision support systems.

Assessing the accuracy of ICD-10 coding for measuring rates of and mortality from acute kidney injury and the impact of electronic alerts: an observational cohort study

BACKGROUND

The application of a uniform definition for acute kidney injury (AKI) is vital to advance understanding and management of AKI. International Classification of Diseases (Tenth Revision) (ICD-10) coding is frequently used to define AKI, but its accuracy is unclear. The aim of this study was to determine whether ICD-10 coding is a reliable method of monitoring rates and outcomes of AKI in inpatients compared with biochemically defined AKI, and whether electronic alerts (e-alerts) for AKI affect ICD-10 AKI coding.

METHODS

An observational cohort study of all 505 662 adult admissions to acute hospitals in two Scottish Health Boards [National Health Service (NHS) Tayside and NHS Fife] from January 2013 to April 2017 was performed. AKI e-alerts were implemented in NHS Tayside in April 2015. Sensitivity, specificity, positive and negative predictive values of ICD-10 coding for AKI compared with biochemically defined AKI using the Kidney Disease: Improving Global Outcomes definition and relative risk of 30-day mortality in people with ICD-10 and biochemically defined AKI before and after AKI e-alert implementation were performed.

RESULTS

Sensitivity of ICD-10 coding for identifying biochemically defined AKI was very poor in both health boards for all AKI (Tayside 25.7% and Fife 35.8%) and for Stages 2 and 3 AKI (Tayside 43.8% and Fife 53.8%). Positive predictive value was poor both for all AKI (Tayside 76.1% and Fife 45.5%) and for Stages 2 and 3 AKI (Tayside 45.5% and Fife 36.8%). Measured mortality fell following implementation of AKI e-alerts in the ICD-10-coded population but not in the biochemically defined AKI population, reflecting an increase in the proportion of Stage 1 AKI in ICD-10-coded AKI. There was no evidence that the introduction of AKI e-alerts in Tayside improved ICD-10 coding of AKI.

CONCLUSION

ICD-10 coding should not be used for monitoring of rates and outcomes of AKI for either research or improvement programmes.

Implementation of clinical decision support to manage acute kidney injury in secondary care: an ethnographic study

BACKGROUND

Over the past decade, acute kidney injury (AKI) has become a global priority for improving patient safety and health outcomes. In the UK, a confidential inquiry into AKI led to the publication of clinical guidance and a range of policy initiatives. National patient safety directives have focused on the mandatory establishment of clinical decision support systems (CDSSs) within all acute National Health Service (NHS) trusts to improve the detection, alerting and response to AKI. We studied the organisational work of implementing AKI CDSSs within routine hospital care.

METHODS

An ethnographic study comprising non-participant observation and interviews was conducted in two NHS hospitals, delivering AKI quality improvement programmes, located in one region of England. Three researchers conducted a total of 49 interviews and 150 hours of observation over an 18-month period. Analysis was conducted collaboratively and iteratively around emergent themes, relating to the organisational work of technology adoption.

RESULTS

The two hospitals developed and implemented AKI CDSSs using very different approaches. Nevertheless, both resulted in adaptive work and trade-offs relating to the technology, the users, the organisation and the wider system of care. A common tension was associated with attempts to maximise benefit while minimise additional burden. In both hospitals, resource pressures exacerbated the tensions of translating AKI recommendations into routine practice.

CONCLUSIONS

Our analysis highlights a conflicted relationship between external context (policy and resources), and organisational structure and culture (eg, digital capability, attitudes to quality improvement). Greater consideration is required to the long-term effectiveness of the approaches taken, particularly in light of the ongoing need for adaptation to incorporate new practices into routine work.

CD4+ T Cell-Derived NGAL Modifies the Outcome of Ischemic Acute Kidney Injury

CD4⁺ T cells mediate the pathogenesis of ischemic and nephrotoxic acute kidney injury (AKI). However, the underlying mechanisms of CD4⁺ T cell-mediated pathogenesis are largely unknown. We therefore conducted unbiased RNA-sequencing to discover novel mechanistic pathways of kidney CD4⁺ T cells after ischemia compared with normal mouse kidney. Unexpectedly, the lipocalin-2 (Lcn2) gene, which encodes neutrophil gelatinase-associated lipocalin (NGAL) had the highest fold increase (∼60). The NGAL increase in CD4⁺ T cells during AKI was confirmed at the mRNA level with quantitative real-time PCR and at the protein level with ELISA. NGAL is a potential biomarker for the early detection of AKI and has multiple potential biological functions. However, the role of NGAL produced by CD4⁺ T cells is not known. We found that ischemic AKI in NGAL knockout (KO) mice had worse renal outcomes compared with wild-type (WT) mice. Adoptive transfer of NGAL-deficient CD4⁺ T cells from NGAL KO mice into CD4 KO or WT mice led to worse renal function than transfer of WT CD4⁺ T cells. In vitro-simulated ischemia/reperfusion showed that NGAL-deficient CD4⁺ T cells express higher levels of IFN-γ mRNA compared with WT CD4⁺ T cells. In vitro differentiation of naive CD4⁺ T cells to Th17, Th1, and Th2 cells led to significant increase in Lcn2 expression. Human kidney CD4⁺ T cell NGAL also increased significantly after ischemia. These results demonstrate an important role for CD4⁺ T cell NGAL as a mechanism by which CD4⁺ T cells mediate AKI and extend the importance of NGAL in AKI beyond diagnostics.