Abstract 12492: Cystatin C is Prognostic for Stroke, Death and Bleeding in Atrial Fibrillation - A RELY Substudy
BACKGROUND Renal insufficiency is associated with a poorer prognosis in healthy elderly people and a wide spectrum of patients with cardiovascular disease. Cystatin C is a low molecular mass protein produced at constant rate in all nucleated cells and removed by glomerular filtration, thereby Cystatin C levels reflect renal function. The prognostic value of Cystatin C and its effect in addition to CHADS2 risk factors for predicting cardiovascular events in patients with atrial fibrillation (AF) has not been investigated previously.
METHODS In the RELY study, 18113 patients (mean age 71 years) with AF and at least one risk factor for thromboembolism and creatinine clearance >30 mL/min were randomized to dabigatran or warfarin and followed for 2.0 years median treatment duration. We analyzed plasma concentrations of Cystatin C at randomization in 6190 patients and evaluated its association to cardiovascular events after multivariable adjustment with Cox proportional-hazard regression models including the CHADS2 risk factors and study drug assignment.
RESULTS Median Cystatin C levels were 1.02 mg/L. The risk for cardiovascular events, death and major bleedings increased significantly according to increasing Cystatin C quartile groups even after multivariable adjustment including CHADS2 risk factors and study drug. C-statistics was improved from 0.59 to 0.66, p<0.001, when adding Cystatin C to the CHADS2 score for the composite outcome of stroke, SE, vascular death (excluding haemorrhagic death), myocardial infarction and pulmonary embolism.
CONCLUSION Elevated Cystatin C levels are related to raised risk of stroke, major bleeding and mortality even after multivariable adjustment including the CHADS2 risk factors in AF patients treated with warfarin or dabigatran.
- © 2011 by American Heart Association, Inc.