Thrombocitopenia in sepsis: an important prognosis factor.

OBJECTIVE: To demonstrate an association between thrombocytopenia and platelet behavior in predicting mortality in septic patients.

METHODS: Patients with criteria for sepsis at admission or at any time during hospitalization were selected; patients hospitalized for less than 24 hours were excluded. Thrombocytopenia was defined as a platelet count lower than 150.000/mm³, and recovery was defined as returning to levels above 150.000/mm³ after showing thrombocytopenia. We assessed the admission prognosis variables (APACHE II), platelet counts during the hospitalization and outcomes.

RESULTS: Of the 56 patients included, 34 developed thrombocytopenia during sepsis (Group 1) and had a 76.4% mortality rate. The mortality rate among patients not showing thrombocytopenia (Group 2) was 40.9% (RR 1.87; 95% CI 1.12 - 3.12; p = 0.0163). In 44.1% of Group 1 patients, the platelet counts drops by >50% compared with the admission counts; 93.3% of these patients eventually died (RR 1.48; 95% CI 0.93 - 2.36; p = 0.0528). Among the Group 1 patients showing recovered platelet counts, 53.3% survived; 100% of the patients with unrecovered thrombocytopenia died (RR 2.14; 95% CI 1.35 - 3.39; p = 0.0003). Among the patients with APACHE II scores > 22, the thrombocytopenic patients had an 81.8% mortality rate (p = 0.25), while no deaths occurred among the non-thrombocytopenic patients. For the patients with APACHE II scores ≤ 22, the mortality rate of the thrombocytopenic patients was 74% (p = 0.0741), versus 42.8% for the non-thrombocytopenic patients.

CONCLUSION: For this sample of septic patients, thrombocytopenia and its progression, defined as a >50% drop or failure to recover platelet count, were shown to be markers of poor prognosis.