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.

Risk factors reported in humans for development of CKD are presented in Table 1.
 

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
 

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).
 

 • 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.
 

High blood pressure, high level of proteinuria, poor glycemic control in diabetes mellitus

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.

1. Levey AS, Coresh J, Balk E, Kausz AT, Levin A, Steffes MW, Hogg RJ, Perrone RD, Lau J, Eknoyan G. National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Ann Intern Med. 2003;139:137-47.
 

2. White JD et al. Naturally-occurring chronic renal disease in Australian cats: a prospective study of 184 cases. Aust Vet J 2006 Jun; 84:188-94
 

3. Lees GE. Juvenile and familial nephropathies. In: Elliot J, Grauer F (eds.). BSAVA Manual of canine and feline nephrology and urology. 2nd edn BSAVA, 2007:79-86
 

4. Vaden SL. Glomerular diseases. In: In Ettinger S, Feldman EC (eds). Textbook of Veterinary Internal Medicine, 6th edn, Elsevier Saunders, St Louis 2005:1787-1800.
 

5. Grauer GF. Management of glomerulonephritis. In: Elliot J, Grauer F (eds.). BSAVA Manual of canine and feline nephrology and urology. 2nd edn BSAVA, 2007:231-238

Bruskiewicz KA, et al. Diabetic ketosis and ketoacidosis in cats: 42 cases (1980-1995). J Am Vet Med Assoc. 1997;15:188-192
 

Cortadellas O, Fernandez del Palacio MJ et al. Systemic hypertension in dogs with leishmaniasis: prevalence and clinical consequences. J Vet Intern Med. 2006;20:941-7.
 

Johnson CA et al. Clinical Practice Guidelines for Chronic Kidney Disease in Adults: Part I. Definition, Disease Stages, Evaluation, Treatment, and Risk Factors. Am Fam Physician 2004;70:869-76
 

Polzin D. Chronic Kidney disease. In Ettinger S, Feldman EC (eds). Textbook of Veterinary Internal Medicine, 6^{th edn, Elsevier Saunders, St Louis 2005:1756-1785}
 

Syme HM, , Elliot J et al. Survival of cats with naturally occurring chronic renal failure is related to severity of proteinuria. J Vet Intern Med. 2006;20:528-35