Antiplatelet drugs and outcome in mixed admissions to an intensive care unit.

Objective: Platelet activation has been implicated in microvascular thrombosis and organ failure. We tested the hypothesis that antiplatelet drugs favorably affect outcome in patients nonelectively admitted to an intensive care unit.

Design: Retrospective cohort study.

Setting: A 22-bed intensive care unit of a tertiary care center.

Patients: Six hundred fifteen consecutive patients admitted to an intensive care unit within 24 hrs after hospitalization were enrolled, approximately 25% of whom received antiplatelet drugs (acetylsalicylic acid, clopidogrel) for secondary prevention of vascular disease. Impact of antiplatelet drugs and established risk factors on mortality were assessed by logistic regression and 2 x 2 table analysis.

Interventions: None.

Measurements And Main Results: Patients on antiplatelet drugs were markedly older and presented higher Acute Physiology and Chronic Health Evaluation II scores on intensive care unit admission. There was no significant difference in injury severity scores in trauma patients with (21 [range, 13-29]) or without antiplatelet drugs (18 [range, 12-29]). Using logistic regression analysis, a significant reduction of mortality was estimated for the use of antiplatelet drugs in various subgroups of patients with normal or high bleeding risk (odds ratios, 0.04-0.34). Significant benefit was also estimated by 2 x 2 table analysis of Acute Physiology and Chronic Health Evaluation II-matched samples (Acute Physiology and Chronic Health Evaluation II >20) of internal medicine patients and/or patients receiving medical treatment. No significant benefit but also no harm of antiplatelet drugs was estimated in Acute Physiology and Chronic Health Evaluation II-matched samples of patients with increased bleeding risk: patients from surgery departments overall, patients with surgical treatment, trauma, active bleeding, or transfusion (odds ratios, 0.51-0.88).

Conclusions: Our data are consistent with prevention of organ dysfunction by antiplatelet drugs, which may be masked in some patients by concomitant bleeding risk. Antiplatelet drugs might offer a novel therapeutic option to prevent organ failure, at least in the absence of active bleeding. This hypothesis warrants testing in a prospective trial.