The Effects of Renal Function and Atrial Fibrillation on Lipoproteins and Clot Structure/Function

6.1 Inclusion criteria WP1: * On anticoagulation therapy * Informed consent obtained WP2: * Not receiving statins prior to recruitment * Diagnosed atrial fibrillation * On anticoagulation therapy * Estimated glomerular filtration rate of \<50 ml/min/1.73m2 * Informed consent obtained 6.2 Exclusion criteria * Age \<18 years * Severe mitral stenosis or presence of metallic prosthetic valve * Active or recent malignancy (\<6 months) * Active immunological disease * Connective tissue disease * Chronic liver disease * Recent or chronic serious infection * Chronic inflammatory disease * Known haemophilia or thrombophilia * Active bleeding * Untreated hypothyroidism or hyperthyroidism * Recent surgery (\<3 months) * Familial lipid disorders * Concurrent use of steroids * Dietary supplements known to influence lipids * Contraindications/inability/unwillingness to commence statin (WP2)