Antiplatelet therapy is associated with reduced mortality in patients with bloodstream infection: a propensity score-matched cohort study.

BACKGROUND: Bloodstream infection (BSI) is associated with a high mortality, ranging from 17 to 32%. Once pathogens enter the bloodstream, they can activate platelets and trigger systemic inflammation. Antiplatelet agents suppress platelet activation and modulate inflammatory responses; however, it remains unclear whether their use reduces mortality in patients with BSI. This study aimed to evaluate the impact of antiplatelet therapy on clinical outcomes in patients with BSI.

METHODS: We retrospectively analyzed patients diagnosed with BSI at Xuanwu Hospital, Capital Medical University, between 2013 and 2023. Patients were categorized into antiplatelet and non-antiplatelet groups. Propensity score matching was performed to minimize potential confounders, including age, sex, body mass index, year of onset, Charlson Comorbidity Index, and anticoagulant therapy. For the primary outcome (30-day all-cause mortality), group differences were analyzed using the logistic regression models, with results reported as odds ratios and 95% confidence intervals. Secondary endpoints, including respiratory failure, septic shock, acute kidney injury, and bleeding events, were similarly compared using the logistic regression. Subgroup analyses were performed according to causative pathogens and types of antiplatelet agents, with covariates showing standardized mean differences >0.1 included in the models.

MAIN RESULTS: After Propensity score matching, a total of 248 patients were included in the analysis, with 124 patients in each group). The 30-day all-cause mortality following BSI diagnosis was significantly lower in the antiplatelet group (OR 0.35; 95% CI 0.17-0.71, P = 0.004). Septic shock, respiratory failure, acute kidney injury, and bleeding events showed no significant differences between groups (OR 1.08; 95% CI 0.50-2.34; P = 0.843, OR 0.72; 95% CI 0.33-1.60; P = 0.424, OR 1.20; 95% CI 0.31-2.33; P = 0.608, OR 0.71; 95% CI 0.55-2.37; P = 0.712). Subgroup analyses revealed that antiplatelet therapy significantly reduced mortality in patients with Gram-negative BSI (OR 0.26; 95% CI 0.08-0.87; P = 0.029). In addition, clopidogrel monotherapy was associated with lower mortality (OR 0.17; 95% CI 0.03-0.90; P = 0.017).

CONCLUSIONS: In patients with BSI, antiplatelet therapy significantly reduced 30-day all-cause mortality without an increasing risk of bleeding.