B2M and ventricular fibrillation: Factors associated with increased risk for mortality in multivariate analyses were serum urea concentrations ≥ 10 mmol/L (OR 2.16, 95% CI 1.11–4.20), absence of initial ventricular fibrillation/ventricular tachycardia (VT/VF) (OR 5.29, 95% CI 2.58–10.87), SOFA score ≥ 10 (OR 4.46, 95% CI 2.00–9.96), and urine β2M levels ≥ 2769 ng/mL (OR 2.65, 95% CI 1.36–5.18).