High-dose antithrombin III in the treatment of severe sepsis in patients with a high risk of death: Efficacy and safety

Objective: To explore if patients with severe sepsis and with a predicted high risk of death (according to the Simplified Acute Physiology Score II) might have a treatment benefit from high-dose antithrombin Ill. Design: Subgroup analysis of a randomized, placebo-controlled, double-blind, prospective phase III study. Setting: Unifactorial and multifactorial reanalysis of prospectively defined populations from the KyberSept trial. Patients. We studied 1,008 patients (43.6% of the overall intention-to-treat population, n = 2,314) with a predicted mortality rate of 30-60% at study entry as defined by the Simplified Acute Physiology Score II. Interventions. Patients were randomized in a 1:1 fashion to receive either high-dose antithrombin III (30,000 IU intravenously over the period of 4 days) or placebo. Measurements and Main Results. In a Kaplan-Meier analysis of patients with a predicted mortality of 30-60%, the survival time when followed up for 90 days after admission was increased in the high-dose antithrombin III group compared with placebo (p =.04). If heparin was avoided during the 4-day treatment phase with high-dose antithrombin III (n = 140) or placebo (n = 162), the treatment effect appeared to be even more pronounced: 28-day mortality rate, 35.7% vs. 44.4% (risk ratio, 0.804; 95% confidence interval, 0.607-1.064); 56-day mortality rate, 39.9% vs. 52.2% (risk ratio, 0.764; 95% confidence interval, 0.593-0.984); 90-day mortality rate, 42.8% vs. 55.1% (risk ratio, 0.776; 95% confidence interval, 0.614-0.986). Like in the overall population, the percentage with any bleeding was increased in patients receiving high-dose antithrombin III compared with placebo. Survival rates were in favor of high-dose antithrombin III in patients both with and without bleeding complications. Conclusions: Treatment with high-dose antithrombin III may increase survival time up to 90 days in patients with severe sepsis and high risk of death. This benefit may even be stronger when concomitant heparin is avoided.