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12 December 2016

posted Dec 12, 2016, 4:50 AM by Beck Lockwood   [ updated Jan 9, 2017, 4:08 AM ]

New tests for Acute Kidney Injury evaluated by NIHR DEC Leeds

New tests for the diagnosis of acute kidney injury among patients in intensive care units (ICUs) are being evaluated using methods pioneered by NIHR DEC Leeds.

A team led by Dr Peter Hall, Visiting Associate Professor at the University of Leeds and Dr Andrew Lewington at Leeds Teaching Hospitals has investigated three different diagnostic tests as part of a Health Technology Assessment programme, funded by the National Institute of Health Research (NIHR). The aim is to provide clear guidance to the UK’s National Institute for Health and Care Excellence (NICE) about what further research may be required to take the tests into the clinic.

Acute Kidney Injury (AKI) is a serious risk in ICUs, affecting around a third of patients. Clinicians currently diagnose AKI using a blood test based on a biomarker called serum creatinine, as well as looking at the amount of urine a patient is passing. These measures are known to be poor markers of AKI as increased levels of serum creatinine and reduced urine volume might not occur until the condition is already quite advanced, so patients with AKI are often diagnosed late, when subsequent treatment is less effective and patients are at increased risk of long term kidney damage.

After conducting a worldwide review of published evidence on existing and developing tests, the team identified over 150 available diagnostics. Of those, three tests called Nephrocheck, NGAL and Cystatin C, were identified as being three of the top priority candidates for clinical evaluation.

Researchers from NIHR DEC Leeds presented early results on the first evaluated test, Nephrocheck®, to the American Society of Nephrology (ASN) during Kidney Week 2016 (15-20 November). Developed by the San Diego-based company, ASTUTE Medical, Nephrocheck® has FDA approval, but the UK’s NICE require further evidence about its clinical utility and cost-effectiveness within a UK setting before considering recommending it for clinical use.

The team developed a decision-analytic model to assess the potential cost-effectiveness of Nephrocheck® from a UK NHS perspective. The model simulated how a patient's health progresses from admission to the ICU, how they might develop AKI, and how their condition might be affected by AKI post-discharge. Within that model they investigated how each test might affect the patient’s treatment and care.

The team also used the model to identify key areas of uncertainty in the current evidence base, which they used to highlight key areas  for future investigation. In particular, they recommended that future research should focus on tracking incidences of AKI over time, to gather more robust evidence about how AKI progresses within ICUs, and that studies are needed to determine how AKI is managed after an early diagnosis, and what impact this has on patients’ health downstream, rather than simply focusing on the accuracy of the tests (which is the focus of most studies to date). They also highlighted that further work is needed to evaluate Nephrocheck against other available tests, and this is one of the next steps that the team plans to undertake.

 “Our investigations do show that Nephrocheck® might be an effective test, which could be cost-effective for the NHS to adopt,” says researcher Alison Smith. “The further research that we’ve recommended, however, would provide more conclusive evidence to inform NICE’s decision.”

She added: “Often there are many new diagnostic tools being developed for a single condition or disease and without a thorough evaluation of all the options deciding which ones to take forward for clinical testing can be a matter of guesswork. Our model is an evidence-informed way of deciding where to focus resources and which new technologies to prioritise.”

The team have already started evaluations of the other two tests, Cystatin C and NGAL, and a final report, which includes a comparative evaluation of all three tests, will be published next year.