Platelets and mortality in bloodstream infection: a multicenter cohort study

Area of Science:

• Hematology
• Infectious Diseases
• Critical Care Medicine

Background:

• Bloodstream infections (BSIs) are a major cause of morbidity and mortality.
• The prognostic significance of thrombocytopenia (low platelet count) in BSIs requires further elucidation.
• Understanding the role of hematologic parameters in BSI outcomes is crucial for patient management.

Purpose of the Study:

• To determine if thrombocytopenia is an independent predictor of mortality in patients with BSIs.
• To compare the impact of platelet counts on mortality versus white blood cell counts and neutrophils.
• To assess the association between varying degrees of thrombocytopenia and 30-day mortality.

Main Methods:

• Retrospective cohort study utilizing two U.S. patient cohorts: a Houston multihospital network and the MIMIC-IV database.
• Inclusion criteria: patients with BSIs and platelet counts within 48 hours before positive blood culture.
• Multivariable logistic regression models were used to analyze the impact of thrombocytopenia severity on 30-day in-hospital mortality.

Main Results:

• Analysis included 21,105 patients (Houston) and 2,710 (MIMIC-IV).
• Severe thrombocytopenia (platelets <50 k/μL) was associated with a significantly increased adjusted odds ratio (aOR) for 30-day mortality (aOR=4.66).
• Moderate and mild thrombocytopenia also showed increased mortality risk (aOR=2.61 and aOR=1.55, respectively), with severe thrombocytopenia posing a higher risk than neutropenia, leukopenia, or leukocytosis.

Conclusions:

• Thrombocytopenia is independently associated with increased mortality in patients diagnosed with BSIs.
• Platelet counts serve as a readily accessible tool for clinicians to risk-stratify patients with BSIs.
• Further research is warranted to investigate the protective mechanisms of platelets in the context of BSIs.