Thrombocytopenia in adult patients with sepsis: incidence, risk factors, and its association with clinical outcome

BACKGROUND Sepsis is a major risk factor for the development of thrombocytopenia, but few studies have specifically evaluated prognostic importance of thrombocytopenia in patients with sepsis. We investigated the incidence, risk factors, and prognostic importance of thrombocytopenia in adult patients admitted to the intensive care unit (ICU) with sepsis. METHODS A retrospective analysis of patients admitted with severe sepsis/septic shock from December 2007 to January 2009 to a 24-bed medical ICU was done. RESULTS A total of 304 patients were included in the study. The patients' mean (±SD) age was 68.8 (±15.8) years. The majority (93.7%) had septic shock, and pneumonia was the most common infection (38.8%). Thrombocytopenia developed in 145 patients (47.6%): 77 (25.3%) at ICU admission and 68 (22.3%) during their hospital course. The median (IQR) duration of thrombocytopenia was 4.4 (1.9-6.9) days. Patients who developed thrombocytopenia had more episodes of major bleeding (14.4% vs. 3.7%, P < 0.01) and received more transfusions. Patients with thrombocytopenia had a higher incidence of acute kidney injury (44.1% vs. 29.5%, P < 0.01), prolonged vasopressor support (median (IQR): 37 (17-76) vs. 23 (13-46) h, P < 0.01), and longer ICU stay (median (IQR): 3.1 (1.6-7.8) vs. 2.1 (1.2-4.4) days, P < 0.01). The 28-day mortality was similar between patients with and without thrombocytopenia (32.4% vs. 24.5%, P = 0.12). However, while 15 of 86 patients (17.4%) who resolved their thrombocytopenia died, 32 of 59 patients (54.2%) whose thrombocytopenia did not resolve died (P < 0.01). The association between non-resolution of thrombocytopenia and mortality remained significant after adjusting for age, APACHE III score and compliance with a sepsis resuscitation bundle (P < 0.01). CONCLUSIONS Thrombocytopenia is common in patients who are admitted to the ICU with severe sepsis and septic shock. Patients with thrombocytopenia had more episodes of major bleeding, increased incidence of acute kidney injury, and prolonged ICU stay. Non-resolution of thrombocytopenia, but not thrombocytopenia itself, was associated with increased 28-day mortality.