Intended for healthcare professionals

Practice Guidelines

Acute kidney injury: summary of NICE guidance

BMJ 2013; 347 doi: https://doi.org/10.1136/bmj.f4930 (Published 28 August 2013) Cite this as: BMJ 2013;347:f4930
  1. Saoussen Ftouh, senior research fellow and project manager1,
  2. Mark Thomas, consultant physician and nephrologist2
  3. on behalf of the Acute Kidney Injury Guideline Development Group
  1. 1National Clinical Guideline Centre, Royal College of Physicians, London NW1 4LE, UK
  2. 2Department of Renal Medicine, Birmingham Heartlands Hospital, Birmingham B9 5SS, UK
  1. Correspondence to: M Thomas mark.thomas{at}heartofengland.nhs.uk

Acute kidney injury is seen in about 15% of adults admitted to hospital in developed countries,1 with elderly people being particularly affected. The definition of acute kidney injury is based on monitoring serum creatinine levels, with or without urine output (see tables 1 and 2 for examples of definitions for adults and children (the “Further information” box on bmj.com discusses controversies in the definition)). In a recent large NHS audit of severe (stage 3) acute kidney injury, mortality across hospitals was consistent at about 30-40% (personal communication, James Medcalf). As acute kidney injury often occurs in people under the care of healthcare professionals other than nephrologists, awareness of the condition needs to be raised among all healthcare professionals, especially those seeing sick or older patients. It is estimated that raising awareness and delivery of optimal care could save about 12 000 lives and £150m in England each year.4 This article summarises the most recent recommendations on acute kidney injury for adults, young people, and children from the National Institute for Health and Care Excellence (NICE).5

Table 1

 Initial detection and staging of acute kidney injury in adults according to Kidney Disease: Improving Global Outcomes (KDIGO) Group2

View this table:
Table 2

 Initial detection and staging of acute kidney injury in children according to pRIFLE (paediatric RIFLE) definition3

View this table:

Recommendations

NICE recommendations are based on systematic reviews of best available evidence and explicit consideration of cost effectiveness. When minimal evidence is available, recommendations are based on the Guideline Development Group’s experience and opinion of what constitutes good practice. Evidence levels for the recommendations are given in italic in square brackets.

Identifying acute kidney injury in adults with acute illness

  • Investigate for acute kidney injury (by measuring serum creatinine concentration and comparing with baseline) in adults with acute illness if any of the following are likely or present:

    • - Chronic kidney disease (adults with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 are at particular risk)

    • - Heart failure

    • - Liver disease

    • - Diabetes

    • - History of acute kidney injury

    • - Oliguria (urine output <0.5 mL/kg/h)

    • - Neurological or cognitive impairment or disability, which may mean limited access to fluids because of reliance on a carer

    • - Hypovolaemia

    • - Use of drugs with nephrotoxic potential (such as non-steroidal anti-inflammatory drugs (NSAIDs), aminoglycosides, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and diuretics) within the past week, especially if hypovolaemic

    • - Use of iodinated contrast agents within the past week

    • - Symptoms or history of urological obstruction or conditions that may lead to obstruction

    • - Sepsis

    • - Deteriorating early warning scores

    • - Age ≥65 years.

[Based on moderate quality evidence from cohort studies and on the experience and opinion of the Guideline Development Group (GDG)]

Identifying acute kidney injury in children and young people with acute illness

  • Investigate for acute kidney injury (by measuring serum creatinine concentration and comparing with baseline) in children and young people with acute illness if any of the following are likely or present:

    • - Chronic kidney disease

    • - Heart failure

    • - Liver disease

    • - History of acute kidney injury

    • - Oliguria (urine output <0.5 mL/kg/h)

    • - Young age or neurological or cognitive impairment or disability, which may mean limited access to fluids because of reliance on a parent or carer

    • - Hypovolaemia

    • - Severe diarrhoea (children and young people with bloody diarrhoea are at particular risk)

    • - Use of drugs with nephrotoxic potential (such as NSAIDs, aminoglycosides, ACE inhibitors, ARBs, and diuretics) within the past week, especially if hypovolaemic

    • - Symptoms or history of urological obstruction or conditions that may lead to obstruction

    • - Sepsis

    • - Deteriorating paediatric early warning score

    • - Symptoms or signs of nephritis (such as oedema or haematuria)

    • - Haematological malignancy

    • - Hypotension.

[Based on low and very low quality evidence from cohort studies and on the experience and opinion of the GDG]

Previous NICE guidance on the acutely ill patient in hospital (clinical guideline 50) was restricted to adults.6 It is expected that the above recommendation will encourage paediatric hospitals to use one of the available paediatric early warning scores to detect deteriorating patients and thus prevent acute kidney injury.

Assessing risk factors in adults having iodinated contrast agents

  • Before offering iodinated contrast agents to adults for emergency or non-emergency imaging, assess their risk of acute kidney injury. Be aware that increased risk is associated with:

    • - Chronic kidney disease (adults with eGFR <40 mL/min/1.73 m2 are at particular risk)

    • - Diabetes, but only with chronic kidney disease (adults with eGFR <40 mL/min/1.73 m2 are at particular risk)

    • - Heart failure

    • - Renal transplant

    • - Age ≥75 years

    • - Hypovolaemia

    • - Increasing volume of contrast agent

    • - Intra-arterial administration of contrast agent.

  • Ensure that risk assessment does not delay emergency imaging.

[Based on low and very low quality evidence from randomised trials, cost effectiveness evidence, and the experience and opinion of the GDG]

Assessing risk factors in adults having surgery

  • Assess the risk of acute kidney injury in adults before surgery. Be aware that increased risk is associated with:

    • - Emergency surgery, especially when the patient has sepsis or hypovolaemia

    • - Intraperitoneal surgery

    • - Chronic kidney disease (adults with eGFR <60 mL/min/1.73 m2 are at particular risk)

    • - Diabetes

    • - Heart failure

    • - Age ≥65 years

    • - Liver disease

    • - Use of drugs with nephrotoxic potential in the perioperative period (in particular NSAIDs after surgery).

Use the risk assessment to inform a clinical management plan.

[Based on very low quality evidence from cohort studies and on the experience and opinion of the GDG]

Ongoing assessment of the condition of patients in hospital

  • When adults are at risk of acute kidney injury, ensure that systems are in place to recognise and respond to oliguria (urine output <0.5 mL/kg/h) if the “track and trigger system” (early warning score) does not monitor urine output. [Based on the experience and opinion of the GDG]

Detecting acute kidney injury

  • Monitor serum creatinine regularly in all adults, children, and young people with or at risk of acute kidney injury. [Based on moderate, low, and very low quality evidence from observational studies and the experience and opinion of the GDG]

Identifying the cause(s) of acute kidney injury

  • Identify the cause(s) of acute kidney injury and record the details in the patient’s notes. [Based on the experience and opinion of the GDG]

The GDG noted that acute kidney injury is a syndrome, not a specific diagnosis, and the cause of the syndrome must be identified.

Ultrasonography

  • When adults, children, and young people have no identified cause of their acute kidney injury or are at risk of urinary tract obstruction, offer urgent ultrasonography of the urinary tract (to be performed within 24 hours of assessment). [Based on low quality evidence from one cohort study and the experience and opinion of the GDG]

This recommendation indicates that ultrasonography is not required for all cases of acute kidney injury, and thus a more targeted approach to the use of ultrasound is required.

Referring to nephrology

  • Discuss the management of acute kidney injury with a nephrologist or paediatric nephrologist as soon as possible, and within 24 hours of detection when one or more of the following is present:

    • - A possible diagnosis that may need specialist treatment (such as vasculitis, glomerulonephritis, tubulointerstitial nephritis, or myeloma)

    • - Acute kidney injury with no clear cause

    • - Inadequate response to treatment

    • - Complications associated with acute kidney injury

    • - Stage 3 acute kidney injury

    • - A renal transplant

    • - Chronic kidney disease stage 4 or 5 (eGFR <30 mL/min/1.73 m2)

[Based on very low quality evidence from cohort studies and the experience and opinion of the GDG]

Information and support for patients and carers

  • Give information about long term treatment options, monitoring, self management, and support to people who have had acute kidney injury (or their parent or carer if appropriate) in collaboration with a multidisciplinary team appropriate to the person’s individual needs. [Based on poorly to very poorly reported observational studies and the experience and opinion of the GDG]

Overcoming barriers

Barriers to preventing and managing acute kidney injury identified by audit and the UK’s National Confidential Enquiry into Patient Outcome and Death (NCEPOD) report7 include failure to appreciate the development or progression of acute kidney injury, or when a patient is at risk of these. NCEPOD and others8 have noted that about 20% of acute kidney injury is avoidable. The NCEPOD report also found disturbing failures in senior review and referral of sick patients with acute kidney injury to critical care. The introduction of laboratory alerts to warn clinicians of a rise in serum creatinine may help them to recognise and respond to the development of acute kidney injury, although the evidence for this is limited. All clinicians and healthcare organisations caring for sick patients should have the skills and systems in place to respond promptly to acute kidney injury and refer when appropriate.

Further information on the guidance

Despite concerns that clinicians may inadvertently contribute to the development of acute kidney injury by use of drugs that are harmful to the kidneys,9 audit was not fully applied to acute kidney injury until the turn of the millennium.8 A seminal moment was the inquiry into the deaths of a large group of adult patients with acute kidney injury published by the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) in 2009.7 This described systemic deficiencies in the care of patients who died of acute kidney injury, including failures in prevention, recognition, and treatment of acute kidney injury and timely access to specialist services. Only 50% of these dying patients received “good” care.7 It was clear that many adult specialties needed to greatly improve their recognition and management of acute kidney injury and redesign their services. There are also known and unacceptable variations in the recognition, assessment, initial treatment, and usage of renal replacement therapy in acute kidney injury. Some 20-30% of cases of acute kidney injury are regarded as partially or fully preventable.7 10 Even if only 20% of cases can be prevented or ameliorated, successful preventive measures would produce a large reduction in deaths, complications, and costs due to acute kidney injury.

Areas of uncertainty remain about the best definition of acute kidney injury:

  • The best measure of premorbid or baseline kidney function remains controversial.11

  • In patients with chronic kidney disease, the importance of a rise in serum creatinine of ≥26 µmol/L (0.3 mg/dL) in acute kidney injury is uncertain. Such a rise is classified as stage 3 (severe) kidney injury in patients with chronic kidney disease by the Kidney Disease: Improving Global Outcomes (KDIGO) definition to indicate higher risk, but it is classified as stage 1 when there is no prior chronic kidney disease. Note that a 30 µmol/L increase from a baseline of 360 µmol/L is a rise of only 8.5%. A small percentage rise such as this could occur from analytical and biological variability in the absence of any acute pathology.12 13

  • The KDIGO definition is the most recent of three related definitions for acute kidney injury in adults. The older definitions are: AKIN (Acute Kidney Injury Network) and RIFLE (Risk, Injury, Failure, Loss, End stage renal disease). A paediatric version of the RIFLE definition (pRIFLE) is in use. KDIGO and pRIFLE are given as examples but NICE does not specifically recommend using any one of the three adult definitions (see full guidance for detailed discussion).

Further research into a simplified definition of acute kidney injury is recognised as being necessary. Even the current first KDIGO definition of acute kidney injury is likely to change in the coming years, but this does not detract from the need for clinicians to routinely use a stage based definition of acute kidney injury.

Methods

The guideline was developed according to standard NICE methods (www.nice.org.uk/guidelinesmanual). The Guideline Development Group (GDG) formulated clinical questions; retrieved and appraised clinical evidence; and evaluated the cost effectiveness of proposed interventions through literature review and original economic modelling. Quality ratings of the evidence were based on Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology (www.gradeworkinggroup.org/). These relate to the quality of the available evidence for assessed outcomes rather than the quality of the clinical study. Quality assessment of diagnostic studies was based on Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) methodology (www.bris.ac.uk/quadas/quadas-2) and presented in adapted GRADE tables. Where standard methodology could not be applied, a customised quality assessment was undertaken. These were either presented as a narrative summary of the evidence or in adapted GRADE tables (such as for qualitative and prognostic reviews).

The draft guideline went through a rigorous reviewing process, in which stakeholder organisations were invited to comment. The GDG took all comments into consideration when producing the final version of the guideline.

The GDG consisted of consultant nephrologists, a renal pharmacist, a consultant paediatric renal physician, a renal nurse practitioner, a consultant clinical scientist, clinical outreach nurse consultant, a consultant in nephrology and critical care, and two patient and carer members, and the NCGC technical team (a senior research fellow and project manager, two research fellows, a senior information scientist, a clinical effectiveness lead, a senior health economist, and an operations director). Advice was also sought from co-opted clinical advisers in radiology, paediatric nephrology, urology, general practice, renal nursing, and elderly care.

Cost effectiveness analysis for prevention of contrast induced acute kidney injury

An economic model was developed from a NHS and Personal Social Services (PSS) perspective to compare the cost effectiveness of eight interventions to prevent contrast induced acute kidney injury. Both sodium bicarbonate and sodium chloride 0.9% are acceptable interventions for the prevention of contrast induced acute kidney injury at a willingness to pay threshold of £20 000 per quality adjusted life year (QALY). Although the addition of N-acetylcysteine to sodium bicarbonate or to sodium chloride 0.9% was among the cost effective strategies, the clinical evidence showed conflicting results on the effectiveness of N-acetylcysteine and the results of the model were therefore based on highly uncertain evidence. In addition, there were some concerns about a possible adverse reaction due to N-acetylcysteine which the model did not account for, and some concerns about practicalities such as the availability of N-acetylcysteine and the fact that it is an unlicensed medicine and consent needs to be sought for its administration. Strategies with sodium chloride 0.45%, N-acetylcysteine with sodium chloride 0.45%, or oral fluids were not cost effective strategies. Sodium bicarbonate in combination with sodium chloride 0.9% was the most effective strategy; however, its incremental cost, due mainly to the extra admission to hospital, is too high for the QALY gain and the incremental cost effectiveness ratio was above the willingness to pay threshold.

Guideline documents

NICE has produced four different versions of the guideline: a full version which includes the methodology and explanatory text of how the GDG came to make the recommendations from the available evidence; a version known as the “NICE guideline,” which summarises the recommendations; a NICE pathway, which is an interactive tool that brings together all related NICE guidance upon a topic in one interface; and a version for patients, carers, and the public. All versions are available on the NICE website (http://guidance.nice.org.uk/CG169).

NICE will conduct a review after publication in accordance with the NICE guidelines manual to determine whether the evidence base has progressed significantly to alter the guideline recommendations and warrant an update.

Future research

The guideline development group identified the following as high priority areas needing further research:

  • What are the long term outcomes of acute kidney injury in adults, children, and young people?

  • What is the clinical and cost effectiveness of rapid referral (within 12 hours) to nephrology services for adults with moderate to severe (stage 2 to 3) acute kidney injury not needing critical care?

  • Can a simplified definition and staging system based on SI units be used to predict short to medium term outcomes in acute kidney injury?

  • What is the clinical and cost effectiveness of early versus later introduction of renal replacement therapy in patients with acute kidney injury stages 2 and 3 when there is no urgent need for therapy?

  • What is the clinical and cost effectiveness of continuing treatment with angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor antagonists (ARBs) versus stopping treatment 24 hours before cardiac surgery and resuming 24 hours after, in people with chronic kidney disease and an estimated glomerular filtration rate of <30 mL/min/1.73 m2?

Notes

Cite this as: BMJ 2013;347:f4930

Footnotes

  • This is one of a series of BMJ summaries of new guidelines based on the best available evidence; they highlight important recommendations for clinical practice, especially where uncertainty or controversy exists.

  • The members of the Guideline Development Group were Mark Thomas (chair), Annette Davies, Anne Dawnay, Mark Devonald, Coral Hulse, Chris Laing, Andrew Lewington, Fiona Loud, David Milford, Marlies Ostermann, Nicholas Palmer, and Sue Shaw. The technical team at the National Clinical Guideline Centre included Joanna Ashe, Caroline Blaine, Elisabetta Fenu, Saoussen Ftouh, Ralph Hughes, Susan Latchem, and Izaba Younis. The co-opted expert advisers were Mark Downes, Lyda Jadresic, John Lemberger, Shelagh O’Riordan, Rajib Pal, and Mark Rigby

  • Contributors: All authors contributed to the conception and drafting of this article and revising it critically. They have all approved this version. Elisabetta Fenu contributed the health economics methods section. MT is the guarantor.

  • Competing interests: We have read and understood the BMJ Group policy on declaration of interests and declare the following interests: we were funded by NICE for the submitted work, no other relationships or activities that could appear to have influenced the submitted work.

  • Provenance and peer review: Commissioned; not externally peer reviewed.

References

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