Prognostic value of serum cystatin C concentration in dogs with myxomatous mitral valve disease.

BACKGROUND: Impaired renal function is 1 of the poor prognostic factors in dogs with myxomatous mitral valve disease (MMVD). However, the value of cystatin C (Cys-C), a marker of renal function, as a prognostic marker for MMVD in dogs has not yet been explored. OBJECTIVE: This study aims to investigate the prognostic value of Cys-C in dogs with MMVD. ANIMALS: Fifty client-owned small-breed dogs with MMVD were included in this study. METHODS: This is a retrospective, cross-sectional study. The prognostic value of serum Cys-C concentration was assessed using univariable and multivariable Cox hazard regression analyses. Kaplan-Meier survival curves for MMVD-specific survival in dogs stratified into high and low Cys-C groups were generated and analyzed using the log-rank test. RESULTS: Serum Cys-C concentrations were significantly associated with MMVD-related death (P < .01) in both univariable (hazard ratio [HR], 5.086; 95% confidence interval [CI], 1.950-13.270) and multivariable Cox hazard regression analysis (HR, 4.657; 95% CI, 1.767-12.270). The high Cys-C group (n = 14) had a significantly shorter MMVD-specific survival time than the low Cys-C group (n = 36; P < .01). In dogs with normal blood creatinine concentrations, the high Cys-C group (n = 10) had a significantly shorter MMVD-specific survival time than the low Cys-C group (n = 36; P < .01). CONCLUSIONS AND CLINICAL IMPORTANCE: High serum Cys-C concentrations were associated with a worse prognosis of MMVD. Furthermore, serum Cys-C could be a predictor of MMVD prognosis even in dogs with normal blood creatinine concentration.

Effect of age, sex, and breed on serum cystatin C and creatinine concentrations in dogs.

This study investigated the effects of age, sex and breed on serum cystatin C (Cys-C) and creatinine in small breed dogs. This retrospective study included 250 dogs weighing less than 15 kg without azotemia. Serum Cys-C and creatinine concentrations were analyzed, along with their correlation with age, and the difference between sexes or dog breeds. Serum Cys-C concentration correlated with age (P < 0.001), and did not differ between sexes or dog breeds. By contrast, serum creatinine concentration did not correlate with age. Serum creatinine concentration was higher in males than females (P < 0.05), and was lower in Miniature Dachshunds and Chihuahuas, and was higher in Shiba Inus compared to the general study population (P < 0.001). Serum Cys-C concentration correlates with age, and might be more sensitive to aging-associated subclinical renal dysfunction than serum creatinine concentration in dogs. Unlike serum creatinine concentration, serum Cys-C concentration is not affected by sex or dog breed.

Evaluation of monitoring methods in asymptomatic dogs with high serum cystatin C concentrations.

This study evaluated the monitoring methods in asymptomatic dogs with high serum cystatin C (Cys-C) concentrations. Ten dogs with high serum Cys-C were divided into two groups based on the owner's choice; one receiving clinical pathology-based monitoring at an animal hospital specialised in chronic kidney disease, and the other receiving symptom-based monitoring at home, partly because they showed no clinical symptoms. The dogs that received the clinical pathology-based monitoring led to an early treatment intervention, resulted in a longer survival period than dogs received the symptom-based monitoring (P<0.05). It became clear that early treatment intervention by clinical pathology-based monitoring extends the renal survival period even in asymptomatic dogs with increased serum Cys-C concentrations.