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.