Muscle Mass Is a Better Predictor of Survival in Dogs With Chronic Kidney Disease Compared to Body Condition Score

Monitoring prognostic factors, such as body weight, is important to assess the effectiveness of therapies in patients with chronic kidney disease (CKD) and estimate the survival rate (SR). As established in the literature, both body condition score (BCS) and muscle mass score (MMS), when analysed individually, show a positive correlation with SR in dogs with CKD. However, no studies have analysed the correlation between both parameters on SR. The present study aimed to clarify the real influence of fat and lean mass on the SR in dogs with CKD, based on a Cox proportional hazards regression analysis, to improve the nutritional management of these patients. This study included 120 client-owned adult dogs diagnosed with CKD stages 2, 3, or 4. The hazard ratios for stage, BCS, MMS, age, and sex were estimated in univariate and multivariable analyses. The results showed survival was not influenced by BCS alone but was influenced by MMS. Severe muscle mass loss (MMS 0) had a 3.85-fold risk of mortality when compared to normal muscle mass (p = 0.006). Regardless of body condition, the present study observed that what really influenced the survival of dogs with CKD, considering the stage, was muscle mass.