Risk factors in dogs and cats for development of chronic kidney disease
MJ Fernández-del Palacio DVM, PhD, DipECVIM-CA
Hospital CLinico Veterinario, Departamento de Medecina y CIrugia Animal, Universidad de Murcia, Murcia, Spain
Epidemiological studies show an increased risk of chronic kidney disease (CKD), among animals with certain clinical and demographic characteristics. This suggests that there are risk factors for CKD. In principle, prevention of adverse outcomes of CKD could be facilitated by evaluating individuals with risk factors to enable earlier detection Likewise risk factor reduction in individuals without CKD might prevent or slow the development of CKD.
The prevalence of patients (people, dogs and cats) at risk for CKD has not been determined. However, the number of these at-risk patients is likely to far exceed the number of patients with CKD.
A risk factor is defined as an attribute that is associated with increased risk of an outcome. The relationship between the risk factor and the outcome may be either causal or non-causal. Causal risk factors are determinants of the outcome, and successful intervention to reduce exposure to them could improve outcomes. Non-causal risk factors may be associated with the outcome through confounding or reverse causation. Interventions to reduce exposure to non-causal risk factors might not necessarily improve outcomes.
Types of risk factors
Risk factors reported in humans for development of CKD are presented in Table 1.
Table 1. Risk factors for chronic kidney disease (CKD) in humans
Modified from National Kidney Foundation1
Factors that increase susceptibility to kidney damage
Increasing age, familial history of CKD, reduction in kidney mass, low birth weight, race/ethnicity, low income or educational level
Factors that directly initiate kidney damage
Diabetes mellitus, hypertension, systemic infections or diseases, urinary tract disease,, drug toxicity
Factors that worsen or accelerate kidney damage
Proteinuria, higher blood pressure , poor glycemic control in diabetes mellitus
Factors that increase morbidity and mortality
anaemia, low serum albumin level, various dialysis factors such as late referral
The difficulty in detecting the early stages of CKD makes it difficult to determine whether the risk factors so far identified relate more to susceptibility, initiation or progression.
Susceptibility factors in dogs and cats
Susceptibility factors in dogs and cats
1. Cats are at greater risk than dogs (between 3 and 10 times greater) of developing CKD. The incidence of CKD in cats was 1.6% versus 0.9% in dogs (Veterinary Medical Data Base, University of Purdue).
2. Breed: familial diseases have been reported to be related to specific breeds, in dogs and cats (Table 2). Maine Coon, Abyssinian, Siamese, Russian Blue and Burmese have been reported most commonly affected in some studies, but not in others2
3. Age: both dogs and cats may develop CKD at any age. Juvenile onset CKD is the most common consequence of familial renal diseases. With these exceptions, CKD is most frequent in cats? older than 9 years. Male cats may develop signs of CKD younger than females (males 12 years; females 15 years;) 2.
4. Gender: no gender-based risk of CKD has been reported in the general population, although idiopathic membranous glomerulopathy has been reported to be more frequent in male cats.
5. Exposure to certain chemical and environmental conditions: dogs and cats living in endemic areas are exposed to some infectious diseases known to cause CKD (dirofilariasis, leishmaniasis, erhlichiosis etc).
Table 2. Familial nephropathies in dogs an cats3
Lhasa Apso, Shih Tzu, Standard Poodle, Soft-Coated Wheaten Terrier, Chow-Chow, Alaskan Malamute, Miniature Schnauzer, Dutch Kooiker, Golden Retriever
Abyssinian (autosomal dominant with incomplete penetrance suspected), Siamese, Oriental
Initiation factors of CKD in dogs and cats
• Glomerular diseases are a leading cause of renal disease in dogs. They can be primary, or secondarily associated with other diseases such as infectious diseases, neoplasia, inflammatory causes and miscellaneous (Tables 3 and 4).
• Tubulointerstitial diseases are a common cause of CKD in cats. A specific relationship between this type of CKD and urinary tract infections, stones, obstructions and toxic drugs has been reported in humans.
Table 3. Diseases associated with glomerular disease in dogs4,5
• Other clinical factors: sequelae of acute renal failure, urinary tract infections, urinary stones, obstruction of lower urinary tract, diabetes, hypercalcemia, heart failure.
• Drugs: aminoglycosides, sulfonamides, polymyxin B, amphotericin and chemotherapeutic drugs.
High blood pressure, high level of proteinuria, poor glycemic control in diabetes mellitus
Action plan to modify risk factors for developing CKD
1. During routine health care and clinic visits, all patients should be assessed for increased risk of CKD based on signalment and clinical and environmental factors.
2. Owners of patients likely to be at risk for CKD should be advised to have the pet tested for markers of kidney damage and assessment of kidney structure or function: for example, urinalysis (e.g. proteinuria, urine specific gravity etc), haematology, biochemical tests (creatinine ± urea), ultrasonography (familial nephropathies), measurement of glomerular filtration rate, possibly even a renal biopsy.
3. Patients found to have CKD should be evaluated and treated according to specific cause and/or stage of CKD.
4. If a patient of increased risk is found not to have CKD, the owner should be advised to follow a program of risk factor reduction (if appropriate) and the pet should be revaluated periodically.
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