even in the absence of azotemia,ref

even in the absence of azotemia,reflects marked renal damage and signals the need for nutritional management regardless of the CKD stage.CLINICAL IMPORTANCE Prevalence of Chronic Kidney Disease CKD is a common cause of morbidity and mortality in dogs and cats. In a survey of 1,600 pet dogs over five years of age examined at a European veterinary college for a variety of reasons,approximately 20% had abnormally increased markers of renal function. It is not known how many of these dogs had kidney disease (Leibetseder and Neufeld, 1991). In a crosssectional study of 31,484 dogs and 15,226 cats evaluated in private practices across the United States in 1995, the prevalence of kidney disease was 2.2% in cats and 0.8% in dogs (Kirk et al,2001).During 1990,the diagnosis of CKD in cats of all ages reported to the Veterinary Medical Data Base was 16 cases/1,000 cats examined.By 2000,diagnosis of CKD in cats of all ages was 96 cases/1,000 cats examined (Ross et al, 2006).Increased diagnosis of CKD in cats may be due to their living longer, more of them being screened for CKD and/or increased awareness of CKD by veterinarians. CKD appears to be a common cause of death in dogs and cats. In a retrospective study of dogs, 2% died from chronic nephritis, 2% from pyelonephritis and 1% from glomerulonephritis (Bronson, 1982). Thus, the overall mortality from kidney diseases was 5%.With the exception of cancer,kidney disease was the most common cause of death in this study. In a 1991 survey by the Morris Animal Foundation of readers of Companion Animal News, respondents indicated that of 325 cats that had died,94 succumbed to kidney disease (MAF,1991).By comparison,39 of the 325 died of feline leukemia and 45 died due to other causes. Relationship Between Age and KidneyDisease CKD occurs in dogs and cats of all ages, but it is frequently a disease of older pets. In a retrospective study of 70 cats with CKD, diagnosed from 1973 to 1984, ages ranged from nine months to 22 years (mean, 9.2 ± 5.5 years).Nine cats (12.8%) were less than three years old, 24 (34.3%) were four to seven years old and 37 (52.9%) were more than seven years old (DiBartola et al, 1987). In a study of 175 cats diagnosed with CKD in Australia from 2000 to 2003,ages ranged from two to 21 years (mean,13.2 ±3.7 years).However,the majority (69%) were 12 to 18 years old (White et al,2006).The mean age for cats diagnosed with CKD at the Animal Medical Center in New York from 2000 to 2002 was 12.8 ± 4.4 years (Boyd et al, 2008).Analysis of data from university teaching hospitals contributed to the Veterinary Medical Data Base from 1980 to 1990 indicated that 37% of cats with CKD were less than 10 years old, 31% of cats were between 10 and 15 years old and 32% of cats were older than 15 years (Lulich et al,1992).In a 1995 survey of private practices,the mean ages of dogs and cats with kidney disease were 10.2 and 13.2 years,respectively (Kirk et al, 2001). Another study in dogs showed a similar relationship between aging and occurrence of CKD. Prevalence of CKD was reported to be nine cases/1,000 dogs of all ages examined,12.5 cases/1,000 in dogs between seven and 10 years old,24 cases/1,000 in dogs between 10 and 15 years old and 57 cases/1,000 in dogs over 15 years old (Polzin et al,1995). Causes of Kidney Disease Familial Kidney Diseases Juvenile kidney disease increases suspicion of a familial