Abstract
<jats:p>Valid animal models are needed to evaluate how age related changes in kidney function influence healthspan. Aging marmosets frequently develop renal insufficiency with anemia and exhibit reductions in body mass and metabolic rate. However, it remains unclear which age related changes predict survival and which thresholds indicate increased mortality risk. We prospectively evaluated age, body composition, resting energy expenditure, hematology, and blood chemistry as predictors of 3 year survival in female and male marmosets (n = 66), 2 to 16 years of age. Objectives were to identify prognostic markers, define high risk thresholds, and to develop and test a composite risk factor scale for mortality screening in captivity. A 10 variable model showed the best predictive performance in multivariable Cox proportional hazards modeling, and was retained for further analysis (concordance = 0.881, p < 0.001). ROC curves using Youden Index and AUC identified high risk thresholds for predictors in the multivariable model, and threshold defined categories were evaluated by Kaplan Meier survival analysis. The 10 binary risk factors were combined into a composite scale scored from 0 to 10 and tested with Cox regression. The scale explained approximately 42% of variance in survival and each additional risk factor increased mortality risk 1.75 fold (95% CI: 1.43 to 2.14, p < 0.001). Marmosets with 7 or more risk factors exhibited a 19 month reduction in survival, and this high risk threshold predicted 3 year survival with 89.4% accuracy. Results support the scale as a screening tool for mortality risk and highlight the high prevalence of age associated renal disease and anemia in marmosets.</jats:p>