Acute kidney injury: prevention, detection and management

Context

Acute kidney injury, previously known as acute renal failure, encompasses a wide spectrum of injury to the kidneys, not just kidney failure. The definition of acute kidney injury has changed in recent years, and detection is now mostly based on monitoring creatinine levels, with or without urine output. Acute kidney injury is increasingly being seen in primary care in people without any acute illness, and awareness of the condition needs to be raised among primary care health professionals.

Acute kidney injury is seen in 13% to 18% of all people admitted to hospital, with older adults being particularly affected. These people are usually under the care of healthcare professionals practising in specialties other than nephrology, who may not always be familiar with the optimum care of people with acute kidney injury. The number of inpatients affected by acute kidney injury means that it has a major impact on healthcare resources. The costs to the NHS of acute kidney injury (excluding costs in the community) are estimated to be between £434 million and £620 million per year, which is more than the costs associated with breast cancer, or lung and skin cancer combined.

There have been concerns that suboptimal care may contribute to the development of acute kidney injury. In 2009, the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) reported the results of an enquiry into the deaths of a large group of adults with acute kidney injury. This described systemic deficiencies in the care of people who died from acute kidney injury: only 50% of these had received 'good' care. Other deficiencies in the care of people who died of acute kidney injury included failures in acute kidney injury prevention, recognition, therapy and timely access to specialist services. This report led to the Department of Health's request for NICE to develop its first guideline on acute kidney injury in adults and also, importantly, in children and young people.

This guideline emphasises early intervention and stresses the importance of risk assessment and prevention, early recognition and treatment. It is primarily aimed at the non-specialist clinician, who will care for most people with acute kidney injury in a variety of settings. The recommendations aim to address known and unacceptable variations in recognition, assessment, initial treatment and referral for renal replacement therapy. The inpatient mortality of acute kidney injury varies considerably, depending on its severity, setting (intensive care or not), and many other patient-related factors, but in the UK might typically be 25% to 30% or more. In view of its frequency and mortality rate, prevention or amelioration of just 20% of cases of acute kidney injury would prevent a large number of deaths and substantially reduce complications and their associated costs.

In 2023, the NICE surveillance team reported that the recommendation to measure eGFR in all adults with risk factors for acute kidney injury before a contrast scan may lead to unnecessary cancellation of CT scans. In addition, concerns about the risk of iodine-based contrast media have decreased since the recommendations were originally developed. Not all people need eGFR testing before having a scan, but it should be restricted to those at greatest risk. There is also a view that the current eGFR risk threshold is too high. Some recent evidence has shown that contrast media may only pose a risk for people with an eGFR of 30 ml/min/1.73 m² or less. The NICE recommendations were developed in 2013, and since then, several external guidelines have moved away from a 'test all' position to a risk stratification policy. This allows a more personalised consideration of the risks of iodine-contrast media versus the benefits from the scan. The 2024 guideline update has made new recommendations on assessing risk factors for acute kidney injury in adults having iodine-based contrast media.