Abstract
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.