title: Thrombocytopaenia during methicillin-sensitive Staphylococcus aureus bacteraemia.
abstract: The prognostic impact of thrombocytopaenia in Staphylococcus aureus bacteraemia (SAB) has previously been determined at bacteraemia onset only and relevant pre-bacteraemic thrombocytopaenia predisposing parameters have not been accounted for. We evaluated the prognostic impact of low thrombocyte count in SAB excluding pre-bacteraemic factors potentially causing thrombocytopaenia. This was a multicentre retrospective analysis of methicillin-sensitive SAB (MS-SAB) patients. Thrombocyte count was determined at blood culture collection and at days 3 and 7. Thrombocytopaenia was defined as a thrombocyte count less than 150 ×109/L. Patients with chronic alcoholism, liver diseases and haematologic malignancies were excluded. Altogether, 495 patients were identified. Thrombocytopaenia at blood culture and at day 3 associated to endocarditis (p < 0.05 and p < 0.01) and defervescence (p < 0.001 and p < 0.01). Mortality at 90 days was higher for patients with thrombocytopaenia at blood culture collection (26 vs. 16%, p < 0.05), at day 3 (32 vs. 13%, p < 0.01) and at day 7 (50 vs. 14%, p < 0.001). In receiver operating characteristic analyses, thrombocytopaenia predicted a poor outcome at blood culture collection (p < 0.05), at day 3 (p < 0.001) and at day 7 (p < 0.001). When accounting for all prognostic parameters, thrombocytopaenia at day 3 [hazard ratio (HR), 1.83; p = 0.05] demonstrated a trend towards poor outcome, whereas thrombocytopaenia at day 7 (HR, 3.64; p < 0.001) associated to poor outcome. Thrombocytopaenia at blood culture collection was not a prognostic parameter when all prognostic factors were taken into account. However, thrombocytopaenia at day 3 indicated a poor outcome and thrombocytopaenia at day 7 was a significant independent negative prognostic marker that has not been previously reported in SAB.
authors.affiliation: Division of Infectious Diseases, Inflammation Center, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland. erik.forsblom@helsinki.fi.|Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Aurora Hospital, Nordenskiöldinkatu 26, Building 3, P.O. Box 348, 00029, Helsinki, Finland. erik.forsblom@helsinki.fi.
authors.forename: E
authors.identifier: http://orcid.org/0000-0001-9220-8826
authors.initials: E
authors.lastname: Forsblom
authors.affiliation: Division of Infectious Diseases, Inflammation Center, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Tielinen
authors.affiliation: Division of Infectious Diseases, Inflammation Center, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Ruotsalainen
authors.affiliation: Division of Infectious Diseases, Inflammation Center, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Järvinen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000150:complications* / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000382:microbiology / Q000401:mortality / Q000473:pathology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D016019:Survival Analysis; D013921:Thrombocytopenia / Q000209:etiology* / Q000473:pathology*; D055815:Young Adult