NPPB and atrial fibrillation: We collected from electronic medical records detailed demographic data (age, sex, place of residence), comorbidities (hypertension, atrial fibrillation, ischaemic heart disease, diabetes, deep-vein thrombosis, stroke, myocardial infarction, pulmonary embolism, cirrhosis), lifestyle factors (smoking and alcohol consumption), vascular access type (arteriovenous fistula or central venous catheter) and laboratory parameters (haemoglobin, haematocrit, creatinine, albumin, total protein, electrolytes, LDL- and HDL-cholesterol, total cholesterol, INR, APTT, D-dimer, BNP, CK-MB, troponin).