Thrombocytosis is a marker of poor outcome in community-acquired pneumonia

TLDR: Thrombocytosis in patients with CAP is associated with poor outcome, complicated pleural effusion, and empyema and should encourage ruling out respiratory complication and could be considered for severity evaluation.

Abstract: Background: Thrombocytosis, often considered a marker of normal inflammatory reaction of infections, has recently been associated with increased mortality in community-acquired pneumonia (CAP). Methods: We evaluated 2,423 hospitalized patients with CAP. We excluded patients with immunosuppression, neoplasm, tuberculosis or haematological disease. The aim was to assess characteristics and outcomes of patients with CAP and thrombocytosis (platelet count ≥4x10 5 /mm 3 ), compared with thrombocytopenia(platelet count 5 /mm 3 ) and normal platelet count. Results: Fifty-three patients (2%) presented thrombocytopenia, 204 (8%) thrombocytosis and 2,166 (90%) a normal platelet count. Patients with thrombocytosis were younger (p Conclusions: Thrombocytosis in CAP is associated with poor outcome, complicated pleural effusion/empyema. Therefore thrombocytosis in CAP should encourage to rule out respiratory complications and could be considered for severity evaluation.