Chronic kidney disease (CKD) is an unwelcome but all too common presence for the many pet owners who share their lives with ageing and senior pets. In both dogs and cats, the risk of developing CKD increases with age, with the disease affecting up to 44 percent of cats over 15 years old and 12 percent of dogs from 10 to 11 years old (IDEXX Laboratories, 2016; Lees, 2006).
As we see patients achieving longer lifespans due to improvements in husbandry, nutrition and veterinary care, we also potentially see the development of age-related diseases more often.
What is chronic kidney disease?
Chronic kidney disease can be defined as kidney damage that lasts for at least three months. It can be the result of a wide variety of inciting causes, which are generally poorly defined in clinical practice as the development of CKD is often slowly progressive and long after any acute inciting cause, if there is one.
Because of its progressive nature, the early phases of CKD are not always readily apparent to pet owners. But early diagnosis and intervention is a key strategy that can potentially preserve renal function for longer. Recent diagnostic tools such as symmetric dimethylarginine (SDMA) can potentially lead to a diagnosis of CKD earlier than serum creatinine and urine protein:creatinine ratio alone (Grauer, 2019).
Treatment or management?
Unfortunately, curative treatment of CKD is not currently achievable; instead, management goals relate to preserving a good quality of life for the patient for as long as possible. Interventions can include subcutaneous fluid therapy at home, oral and subcutaneous medication, injections, supplements, dietary management, frequent trips to the veterinary practice for rechecks and even hospitalisation for diuresis in acute-on-chronic crises.
Unfortunately, curative treatment of CKD is not currently achievable; instead, management goals relate to preserving a good quality of life for the patient
The stress incurred by any interventions must be considered when determining the quality of life of each individual patient. Additionally, the pet owner’s quality of life and their bond with their pet should be taken into account when deciding on a management course. Some pets take tablets easily or receive injections readily with positive reinforcement, while others will be induced to hide from their owners, leading to stress for both.
Evidence-based principles should apply to clinical decision making to minimise treatment stress and expense, and obtaining the best outcome for the least amount of stress should be the goal.
Several studies have been conducted on interventions for CKD, and much of the International Renal Interest Society (IRIS) guidelines focus on correcting dehydration and managing symptoms (eg nausea and inappetence) as needed (IRIS, 2019a, 2019b). Additionally, dietary management should not be overlooked as a mainstay of treatment because it not only is supported by clinical evidence but is non-invasive and has the potential to be very low stress when implemented with an appropriate dietary transition.
Dietary management should not be overlooked as a mainstay of treatment because it not only is supported by clinical evidence but is non-invasive and has the potential to be very low stress
Dietetic renal foods
The IRIS guidelines recommend considering dietetic renal food for cats and dogs with Stage 2 CKD and feeding such a diet to patients in Stages 3 and 4. The guidelines state that transitioning to dietetic food in the earlier stages of CKD, when a pet is less likely to have symptoms such as nausea and inappetence, may result in higher acceptance of the food.
A wide variety of well-designed studies have shown better clinical outcomes for dogs and cats fed dietetic renal foods than those that are not, including longer survival time and fewer uraemic episodes (Fritsch et al., 2015; Hall et al., 2018; Quimby and Ross, 2022). These outcomes are exactly what we as veterinary professionals, and the owners of pets with CKD, are attempting to achieve – better quality of life for as long as possible. Indeed, a study evaluating dogs with CKD demonstrated a higher score on a health-related quality of life index for dogs fed a dietetic renal food than dogs eating a maintenance food (Jacob et al., 2008).
The role of individual dietary manipulations
While the evidence is substantial for complete dietetic renal foods, it has been more challenging to understand the role individual dietary manipulations play in the nutritional management of CKD.
Principal nutritional factors for CKD include a combination of controlled protein (while still meeting or exceeding FEDIAF requirements for maintenance), reduced phosphorus, potassium and sodium manipulation, and added omega-3 fatty acids and antioxidants. Given the large range of nutritional factors addressed in successful dietetic renal foods, there are no equivalent commercial non-dietetic foods that meet all these key nutritional factors and have been clinically proven to achieve the same positive outcomes.
Recent advancements in palatability, essential amino acid profiles and the variety of renal dietetic foods have resulted in high acceptance rates and a satisfactory caloric intake to maintain body weight and muscle mass in CKD patients.
An owner’s perception of their pet’s quality of life often relates to the pet’s appetite and visible condition
Increased acceptance of dietetic diets may also contribute to the owner’s feelings of providing loving care to their pet via a food they enjoy, as an owner’s perception of their pet’s quality of life often relates to the pet’s appetite and visible condition. A well-accepted food that helps maintain the pet’s body and muscle condition can contribute greatly, not just to the pet’s clinical health, but to the owner’s perception of how well the pet is doing.
Communication is key
Open bidirectional communication with pet owners is key to achieving the best outcomes for the pet and owner once a diagnosis of CKD is made. Owners should be informed of the various available options for management, what is likely to become necessary in the future and what to expect from disease progression.
It is just as important to give owners a chance to voice their concerns about implementing the recommended treatments for their individual pet and its temperament and needs. These concerns should be considered valid and essential factors when deciding a course of treatment. Frequent follow-up and continued communication about how the pet and owner are doing are necessary for continued positive welfare.
Dietary therapy should be considered early as a mainstay of non-invasive, low-stress and effective management with dogs and cats diagnosed with chronic kidney disease.