IRIS Guidelines

The IRIS Board met on 26th July 2022 and one major agenda item was to discuss updates required to the IRIS CKD staging and treatment recommendations. All board members reviewed these documents ahead of the meeting and items were proposed for discussion at the meeting. Following the meeting, if agreement was reached that updates were required, working groups were charged with suggesting precise amendments to these guidelines which were then presented to the full board for approval.

Staging Guidelines:

The section relating to discrepancies between creatinine and SDMA was felt to be in need of updating to include mention of breed specific reference ranges for both creatinine and SDMA and instances recognised where SDMA is elevated because of non-renal disease (e.g. lymphoma) where creatinine is not elevated. Amendments to the education article on ‘Reassessment of "normal" values in dogs and cats with chronic kidney disease’ will be made to complement the IRIS CKD Staging Guidelines and this revised article will be published in the spring of 2023 to provide further details in this area.

Treatment recommendations for cats:

Four main changes have been introduced to the cat treatment recommendations. These are:

1. The recommendation that clopidogrel should be the first line drug recommended for cats with protein losing nephropathy considered at risk of thromboembolic disease and the removal of serum albumin (<2.0 g/dl) as a definitive trigger for such therapy.

2. The introduction of FGF23 as a means of assessing cats with serum phosphate concentrations within the IRIS target range for each stage to determine the need for dietary phosphate restriction (in Stages 1 and 2 where phosphate is in the target range at initial staging) or for enhanced restriction when initial dietary treatment has reduced serum phosphate into the target range. This follows the commercial availability of FGF23 as a diagnostic marker in the USA in 2022 and its expected availability elsewhere in the world in 2023. An in-depth education article on FGF23 has been written to accompany these changes.

3. The removal of the mention of calcitriol treatment for cats in the management of Stage 3 and 4 CKD due to lack of any evidence of a beneficial effect.

4. Introduction of a recommendation to treat stage 2 cats for vomiting/decreased appetite/ nausea/weight and/or muscle loss whilst recognising that SDMA might be used to stage cats with significant muscle loss and that investigations for concomitant diseases leading to vomiting should also be undertaken.

Treatment recommendations for dogs

The main changes introduced for the dog treatment recommendations were as follows:

1. In the management of proteinuria at all stages it was recommended that:

   a. Reduction of UPC below 0.5 was not possible in many patients with primary glomerular disease and that a more realistic treatment goal is a 50% reduction in UPC from pre-treatment baseline and to achieve the lowest UPC possible without causing harm

   b. Angiotensin receptor blockers should be the first line treatment rather than ACE inhibitors together with a clinical renal diet. This change is based on recent published evidence of randomised controlled clinical trials.

   c. There is no reliable predictor of thromboembolic complications of protein-losing nephropathy and that antithrombotic therapy cannot be guided by serum albumin concentration. The first line drug antithrombotic treatment should be clopidogrel with aspirin as an alternative.

2. An additional consideration has been inserted for dogs with stage 2 CKD and that is to treat suspected nausea and decreased appetite leading to weight and /or muscle loss.

3. The recommendation to use calcitriol treatment to manage bone mineral disorder in stages 3 and 4 has been removed. This decision came after some debate and was not unanimous. A majority of IRIS Board members felt that there was insufficient evidence to support this statement as a hard recommendation with some concerned that close monitoring, particularly of ionised calcium, that is necessary when using calcitriol treatment is not always easy to follow in general practice settings.

As the leader in veterinary nephrology, IRIS has a responsibility to provide practicing veterinarians with evidence-based guidance for diagnosing, treating, and managing kidney disease. Our responsibility includes providing the most useful direction on how to interpret diagnostic information. The inclusion of SDMA values in the IRIS CKD Staging Guidelines is the next step in improving not only early diagnosis of CKD but also tailoring treatment of CKD to individual patients. The IRIS Board recommends using both serum creatinine and SDMA to enhance our ability to evaluate renal excretory function. These two surrogate markers are complimentary to each other. Another change the IRIS board has recently made is the expansion of Stage 2 for dogs and a corresponding reduction in size of Stage 3 for dogs. This change was made to reduce the large variability in clinical signs and treatment needs for dogs in the previously large IRIS Stage 3 category.

Staging of chronic kidney disease (CKD) is undertaken following the diagnosis of CKD in order to facilitate appropriate treatment and monitoring of the patient. Staging is based initially on fasting blood creatinine, assessed on at least two occasions in the stable patient. The patient is then substaged based on proteinuria and systemic blood pressure.

Based on these categories, some empirical recommendations can be made about the type of treatment it would be logical to use for these cases. In addition, predictions based on clinical experience might be made about the likely response to treatment.

» IRIS Staging of CKD (modified 2023) - (PDF)

» IRIS CKD Pocket Guide

All treatments for chronic kidney disease (CKD) need to be tailored to the individual patient. The following recommendations are useful starting points for the majority of animals at each stage. Serial monitoring of these patients is ideal and treatment should be adapted according to the response to treatment.

Some of the suggested treatments are not authorised for use in dogs and/or cats and recommended dose rates are therefore empirical. It is the veterinarian's duty to make a risk:benefit assessment for each patient prior to administering any treatment.

» IRIS Treatment Recommendations (modified 2023, PDF)
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DISCLAIMER: Although every effort has been made to ensure the completeness and accuracy of the information provided herein, neither the IRIS Board nor Elanco Animal Health assumes any responsibility for the completeness or accuracy of the information. All information is provided "as is" without any warranties, either expressed or implied.

Acute kidney injury (AKI) represents a continuum of renal injury from mild, clinically inapparent, nephron loss to severe acute renal failure. To emphasize the concept of AKI as a continuum, IRIS recommends that it be graded to accurately characterize the severity of the disorder. The IRIS AKI Grading scale (I-V) for dogs and cats is based on fasting blood creatinine determination and clinical parameters, such as urinary flow rate.

The development of this scheme was led by Dr. Larry Cowgill of the IRIS Board and was adopted by the IRIS Board, provisionally in 2012 and finally in 2013. The IRIS Board is now seeking feedback and recommendations for modifications from the American and European Societies of Veterinary Nephrology and Urology (ASVNU and ESVNU) and from the wider veterinary community.

The IRIS AKI Grading scheme is intended to aid the development of appropriate prognoses in patients with AKI. In the future, the Board intends to expand these guidelines to include recommendations for diagnostic testing and for treatment and monitoring of AKI, paralleling the widely accepted IRIS guidelines for Staging and Treatment of Chronic Kidney Disease (CKD).

» IRIS Treatment Recommendations (modified 2023, PDF)

IRIS Consensus Recommendations for Treatment of Canine Proteinuric Kidney Disease

At its 2011 meeting in Denver, the IRIS Board approved the formation of a study group to develop a consensus report entitled "Best Clinical Practices for Proteinuric Kidney Disease in Dogs". Two Board members, David Polzin and Larry Cowgill, serve as the co-Chairs of this group. The aim of the project was to utilize currently available evidence and group consensus to develop a series of clinically applicable recommendations for diagnosis and management of these patients.

To cover the wide array of patient presentations, geographic variance and means available following focused topics were developed:

1. Diagnostic Investigation of Dogs with Suspected Glomerular Disease,

2. Standard Therapy of Dogs with Suspected Glomerular Disease,

3. Immunosuppressive Treatment of Dogs with Glomerular Disease Based on Established Pathology,

4. Immunosuppressive Treatment of Dogs with Proteinuric Kidney Diseases Absent Histopathologic Diagnosis,

5. Immunosuppressive Treatment of Dogs with Suspected Glomerular Disease and Serologic Evidence of A Possible Causative Agent.

Further details on this project are available in the IRIS Newsletter. This work is published as a supplement to the Journal of Veterinary Internal Medicine and is available online. The Board hopes this project will serve as a model for the development of future recommendations in nephrology, as well as other fields in veterinary medicine. The development of this report, and its inclusion as a journal supplement, were graciously supported by Novartis Animal Health, acquired by and now supported by Elanco Animal Health, a division of Eli Lilly and Company.