Preventive Antibiotics in Stroke Study (PASS): A cost-effectiveness study

OBJECTIVE: To evaluate the cost-effectiveness of preventive ceftriaxone vs standard stroke unit care without preventive antimicrobial therapy in acute stroke patients.

METHODS: In this multicenter, randomized, open-label trial with masked endpoint assessment, 2,550 patients with acute stroke were included between 2010 and 2014. Economic evaluation was performed from a societal perspective with a time horizon of 3 months. Volumes and costs of direct, indirect, medical, and nonmedical care were assessed. Primary outcome was cost per unit of the modified Rankin Scale (mRS) and per quality-adjusted life year (QALY) for cost-effectiveness and cost-utility analysis. Incremental cost-effectiveness analyses were performed.

RESULTS: A total of 2,538 patients were available for the intention-to-treat analysis. For the cost-effectiveness analysis, 2,538 patients were available for in-hospital resource use and 1,453 for other resource use. Use of institutional care resources, out-of-pocket expenses, and productivity losses was comparable between treatment groups. The mean score on mRS was 2.38 (95% confidence interval [CI] 2.31-2.44) vs 2.44 (95% CI 2.37-2.51) in the ceftriaxone vs control group, the decrease by 0.06 (95% CI -0.04 to 0.16) in favor of ceftriaxone treatment being nonsignificant. However, the number of QALYs was 0.163 (95% CI 0.159-0.166) vs 0.155 (95% CI 0.152-0.158) in the ceftriaxone vs control group, with the difference of 0.008 (95% CI 0.003-0.012) in favor of ceftriaxone (p = 0.006) at 3 months. The probability of ceftriaxone being cost-effective ranged between 0.67 and 0.89. Probability of 0.75 was attained at a willing-to-pay level of €2,290 per unit decrease in the mRS score and of €12,200 per QALY.

CONCLUSIONS: Preventive ceftriaxone has a probability of 0.7 of being less costly than standard treatment per unit decrease in mRS and per QALY gained.