Abstract P295: Exercise Capacity and Rate of Progression to Chronic Kidney Disease

Abstract

Introduction: Increased exercise capacity is associated with better health outcomes. It is not known if increased fitness can attenuate the progression to chronic kidney disease (CKD). Hypothesis: We assessed the hypothesis that increased exercise capacity is associated inversely with the rate of progression to CKD. Methods: A routine exercise stress was performed on 6,452 veterans (mean age: 58±12) with normal kidney function at VA Medical Centers in Washington DC. We used Cox proportional hazards model with spline function of MET to define the MET level associated with no increase in rate of progression to CKD (hazard ratio (HR)=1.0). We used this MET level to guide the formation of the following four fitness categories based on intervals of 2 METs achieved above and below this threshold: Least-Fit (<5.5 METs; n=1,392); Low-Fit (5.5-7.5 METs; n=2,270); Moderate-Fit (7.6-9.5 METs; n=2,192) and High-Fit (>9.5 METs; n=714). We then performed Cox proportional hazards analysis adjusted for age, BMI, cardiac risk factors, sleep apnea, alcohol dependence and medications. We used the Least-fit category as the reference group. Results: The MET threshold for the entire cohort was defined at 7.5 METs. During the follow-up period (median 8.8 years; 50,371 person-years of follow-up), 925 individuals developed CKD based on an estimated glomerular filtration rate <60 ml/min/1.73m 2 . Cox proportional hazards analysis revealed that exercise capacity was inversely associated with the rate of progression to CKD. More specifically, the rate of progression was lower by 25% (HR=0.75; CI: 0.64-0.87; p<0.001) for Low-Fit individuals, 40% (HR=0.60; CI: 0.48-0.73; p<0.001) for the Moderate-Fit and 68% (HR=0.42; CI: 0.28-0.64; p<0.001) for High-Fit individuals. Conclusions: Exercise capacity is inversely associated with the rate of progression to CKD.