Clinical and laboratory characterization of dogs in different stages of chronic kidney disease and the importance of hyperphosphatemia

Chronic kidney disease (CKD) is a progressive and degenerative disorder that mainly affects elderly dogs. There is no cure for CKD, and since most patients are diagnosed late, when treatment will be ineffective, survival time is short. In order to standardize procedures for the detection and treatment of CKD, the International Renal Interest Society (IRIS) proposed a classification system based on serum creatinine concentration. Hyperphosphatemia is one of the major complications of CKD, which is correlated with high mortality in human patients with this disease. The present study followed 65 dogs with CKD and an average age greater than seven years. The mortality rate was 55%. According to the IRIS staging system of CKD for dogs, 6.2% were in stage 1, 13.8% in stage 2, 38.5% in stage 3, and 41.5% in stage 4 when the study beganAs their condition worsened, in most animals proteinuria and blood pressure increased, but urine density decreased. Most animals in the more severe stages of CKD presented proteinuria, arterial hypertension, and low urinary density. Hyperphosphatemia was associated with high rates of mortality, hypoalbuminemia, hypertension, proteinuria, and disease progression, and mainly occurred in IRIS stages 3 and 4. The use of a renal diet contributed to the control of hyperphosphatemia and increased the survival of dogs with CKD.