Chronic Feline Kidney Disease
With early screenings and the right resources, veterinarians can provide feline patients diagnosed with Chronic Kidney Disease a better quality of life.
For any companion animal veterinary practice that sees feline patients, diagnosing and treating chronic kidney disease (CKD) will be one of the most frequent services provided. Statistically, in cats over seven years of age, about 10% of them have some stage of CKD, said Peter Hann, DVM. And when cats get to be about 15 years old, that number jumps to between 30% and 50%.
“So it’s a very common problem in cats.”
Veterinarians who can have conversations with young kitten owners on the importance of preventive screenings stand the best chance of helping those cats live longer, healthier lives. But there’s one problem with that dynamic, and it’s one that veterinarians have struggled with as long as they’ve been treating feline patients.
“If you can’t see them, there’s not very much you can do to help them out,” said Dr. Hann, who was a general practitioner for 25 years before moving over to the industry side as a technical services veterinarian for Vetoquinol USA.
Indeed, cats typically don’t like coming to the veterinarian. It stresses them out and, in turn, stresses the pet owner out. “That is one of the biggest problems we have in feline medicine,” Dr. Hann said.
And the problem with CKD in cats and dogs is that the clinical signs associated with it aren’t noticeable until the disease has progressed significantly. CKD is a progressive disease. In its initial stages, the kidneys can compensate. But by the time the cat is showing clinical signs, “we’re sort of behind the eight ball already,” Dr. Hann said. “If veterinarians could screen for CKD earlier in the cat’s life and catch it earlier in the progression before the clinical signs begin to show, we will have a whole lot better luck treating it.”
Slowing the progression
CKD occurs when the patient progressively loses more and more of the filtering capacity of the kidney. There are thousands of nephrons, the basic filtering unit of the kidney. Once a nephron is lost, it’s gone forever. Fortunately, both pets and people have thousands of them. It takes the loss of two-thirds of nephrons before the earliest signs begin to show and close to three-quarters of nephrons lost before more severe clinical signs of the disease appear.
Thus, the goal for veterinarians needs to be to slow the progression of nephron loss and try to either prevent or postpone the creation of uremia, which is one clinical sign associated with CKD. The best way to do this is to reduce the workload on individual nephrons.
Yet if the owner doesn’t bring the cat in until the later stages of the disease, there may only be invasive or expensive treatment options available to them, such as fluid therapy. If caught early, veterinarians can recommend things like restricting phosphorus intake in the diet or reducing the total protein intake by making sure the diet consists of lower quantities and higher qualities of proteins. “This can slow the progression of the disease and allow the cats to live longer lives,” said Dr. Hann. “The sooner we can recognize the fact that they’re in trouble and reduce the workload on the kidneys, the longer that patient will live, and the happier and healthier it will be.”
Another barrier to treatment is the palatability of renal diets. Although clinically effective, many renal diets taste like cardboard to the cats, Dr. Hann said. “Cats with CKD are notoriously inappetent, and any loss in palatability can reduce the amount of food consumed, which doesn’t allow even the most well-formulated specialty diet to work effectively.” While veterinarians can’t change a cat’s taste preferences, they can at least provide supplements that wouldn’t affect palatability and still achieve some of the health goals, such as managing uremic toxins, phosphorus restriction, or supplementing potassium. “Supplements are not invasive, and some are not associated with food intake, which can be less challenging to give to cats who aren’t interested in eating,” he said. “For the pet owner, it’s not as difficult to deliver these beneficial ingredients and can be affordable, too.”
The right resources
For distributor reps, Dr. Hann said question-based interviewing techniques would work well in determining whether a veterinarian has the right products and services in place to treat cats with CKD. For instance, asking the veterinarian questions like: “Can you tell me about what you’re doing to stimulate cat visits?” or “Do you have a problem getting your feline patients into the practice?” will provide the veterinarian with an open-ended way to share information.
From that point, reps can ask questions to determine if the veterinarians are set up to take steps to address the issues and determine whether they have the resources needed. It’s not so much the reps positioning themselves as the experts, Dr. Hann said, as it is reps offering to be a resource or conduit to those experts that may have solutions, whether it’s to increase cat visits overall or clinically address CKD patients and improve outcomes.
“If you give veterinarians a sort of cookbook on how to get this started, they are a lot more likely to do this,” Dr. Hann said. “Rather than saying, ‘I don’t know how you do it, but you need to be doing this for cat visits,’ if you provide them with resources so that perhaps they could delegate this task to a practice manager, maybe they will implement some changes in the practice. But it’s an attitude change, I believe.”
One resource that Dr. Hann recommends distributor reps mention to veterinarians is the International Renal Interest Society (IRIS) CKD staging system. IRIS was created to advance the scientific understanding of kidney disease in small animals and is led by a board of 14 independent veterinarians with particular expertise in nephrology, from eight different countries, according to the society’s website. The mission of IRIS is to help veterinary practitioners better diagnose, understand and treat renal disease in cats and dogs. In order to achieve this mission, the group investigates ways to accurately diagnose early signs of chronic kidney diseases and acute kidney injury and explores novel therapies for these diseases.
The following are stages created by the society to aid veterinarians:
1. Staging of CKD based on blood creatinine and SDMA concentrations
Staging is undertaken following the diagnosis of CKD to facilitate appropriate treatment and monitoring of the canine or feline patient. Staging is based initially on fasting blood creatinine or fasting blood SDMA concentration or (preferably) both assessed on at least two occasions in a hydrated, stable patient.
2a. Substaging by proteinuria
The goal is to identify renal proteinuria, having ruled out post-renal and pre-renal causes. Standard urine dipsticks can give rise to false positives; therefore, practitioners should consider using a more specific screening test, such as the urine protein to creatinine ratio (UP/C) of a species-specific albuminuria assay.
2b. Substaging by blood pressure
Canine and feline patients should be acclimatized to the measurement conditions and multiple measurements taken. The final classification should rely upon multiple systolic blood pressure determinations, preferably done during repeated patient visits to the clinic on separate days, but acceptable if during the same visit with at least two hours separating determinations.
3. Revision of staging and substaging after treatment
The stage and substages assigned to the patient should be revised appropriately as changes occur. For example, a substantial increase in blood creatinine or SDMA concentration might warrant reassignment to a higher stage to reflect the new situation.
(Editor’s note: For the complete guidelines, visit iris-kidney.com/pdf/IRIS_Staging_of_CKD_modified_2019.pdf )
Dr. Hann said the IRIS CKD staging system provides veterinarians a reference point to quickly recognize what stage a patient is in, and the steps needed to be taken to improve or maintain the pet’s quality of life. “It goes back to the idea that CKD is progressive,” he said. “So how do we measure what stage the cat or the dog happens to be in with this progressive disease? Are we early on in it? Are there some very clear early clinical signs that we can be aware of?”
The IRIS CKD staging system is also one of several ways distributor reps can demonstrate to their customers that they play an important role in bettering the lives of cats with CKD. Dr. Hann said many practicing veterinarians may not be aware of the IRIS staging system or other resources.
By sharing resources, reps provide value to their practices, “which is critically important,” Dr. Hann said. “If you’re trying to sell things, you must be able to provide value to the practitioner. And if you can do that, just by showing them this information can be quite useful.”
Why Is Staging Important?
- Uniform terminology and better comparison between studies (e.g., terms such as end-stage renal disease/failure and renal insufficiency are often poorly defined)
- Diagnostic and therapeutic efforts better tailored to the patient
- More accurate prognoses for progression and life expectancy
- Aids in monitoring response to treatment
Source: “Staging and Managing Chronic Kidney Disease in Cats, Gregory F. Grauer, DVM, MS, DACVIM, Vetoquinol resource
Clinical Management
After staging, additional diagnostics, as well as therapeutics, should be guided by the patient’s CKD stage. The clinician should focus on three key areas:
- Renal Evaluation: Characterize primary renal disease and/or complicating factors. Include diagnostics to rule out potentially treatable primary diseases (e.g., renal lymphosarcoma through renal imaging and fine needle aspiration and hypercalcemia via ionized calcium) and complications (e.g., ascending UTI and ureteral obstruction through urine culture, renal U/S, abdominal radiographs), then treat appropriately.
- Stability/Progression: Characterize stability of renal disease/function via longitudinal monitoring of renal function parameters (e.g., serum creatinine, SDMA, UPC). Employ renoprotective treatments (e.g., renal diets, enteric phosphate binders, RAAS blockade) for cats with progressive disease.
- Patient-Specific Factors: Characterize patient problems caused by declining renal function (e.g., anorexia, vomiting, dehydration, anemia, hypokalemia, uremia) followed by appetite stimulants, antiemetics, fluid therapy, feeding tubes, recombinant erythropoietin, potassium supplementation, enteric dialysis as necessary.
Source: “Staging and Managing Chronic Kidney Disease in Cats, Gregory F. Grauer, DVM, MS, DACVIM, Vetoquinol resource
Photo credit: istockphoto.com/shironosov
