MO057: Serum Irisin and Prediction of Cardiovascular Events in Elderly Patients with CKD Stage 3–5

Abstract

Abstract BACKGROUND AND AIMS Irisin is a circulating myokine released by skeletal muscle after exercise. Its production decreases in chronic kidney disease (CKD) as a potential consequence of sarcopenia and physical inactivity. Irisin produces beneficial effects in glucose and lipid homeostasis: it promotes glucose tolerance and lipid metabolism and improves insulin resistance, stimulates browning of white adipose tissue and upregulates thermogenesis. Irisin may also produce a protective effect on the cardiovascular system as it promoted the proliferation of cardiomyocytes and suppressed myocardial fibrosis and hypertrophy. Low serum irisin was proposed as a predictor of cardiovascular mortality. We studied the relationship of serum irisin with cardiovascular risk in a sample of patients at different stages of CKD not undergoing dialysis and characterized for their artery calcification and mineral metabolism variables. METHOD Seventy-nine consecutive patients with stage 3–5 CKD were recruited from the patients of the nephrology outpatient clinic of our institute in Milan from 2010 to 2014. Serum irisin levels were measured at baseline in all recruited patients and in 20 healthy controls. Incident cardiovascular events were recorded during a 3-year follow-up. They included myocardial infarction, angina pectoris, coronary revascularization, congestive heart failure, stroke, TIA and cardiovascular death. RESULTS Serum irisin was significantly higher in controls than that in patients with CKD and in patients with CKD stage 3 than that in patients at stage 4 and 5 taken together. Taking controls and patients with CKD together eGFR was positively correlated with serum irisin. Patients with CKD were grouped according to tertiles of serum irisin. Patients in the lowest tertile had lower serum 1,25(OH)2D levels than patients in the middle and the highest tertile. Patients in the highest tertile had lower Kauppila aortic calcification score than patients in the middle and the lowest tertiles. Twenty patients suffered from cardiovascular events during a 3-year follow-up. Cox regression analysis confirmed the association of serum irisin with incident cardiovascular events during the follow-up, as patients in the highest tertile of serum irisin showed a lower cardiovascular risk than patients in the middle or the lowest tertile. Kaplan–Meier survival analysis showed that patients in the highest serum irisin tertile developed less cardiovascular events during the follow-up than patients in the other tertiles taken together (P = 0.049). CONCLUSION The present study suggests that irisin is a marker of cardiovascular risk in patients with CKD. It might contribute to the cardiovascular protection that physical exercise and active lifestyle produce in patients with CKD.