Serial Platelet Count and Indices for Predicting In-Hospital Mortality in Sepsis

Overview

This observational study aims to determine if tracking changes in blood platelets over time can help predict the clinical outcomes of adult patients hospitalized with sepsis. While current medical scoring systems (like SOFA and APACHE) help doctors evaluate a patient's risk when they are first admitted, they are often static and may not capture how the body's response changes during the infection. Platelet count and the size of the platelets (mean platelet volume) change dynamically during sepsis. Researchers will observe the routine daily blood test results of adult sepsis patients during their first 7 to 14 days in the hospital to track these changes. By calculating specific platelet ratios and analyzing their trajectories, the study hopes to find out if these simple, cost-effective markers can accurately predict a patient's risk of in-hospital mortality, and if they can improve the accuracy of current standard severity scores.

During sepsis, platelet count (PC) and mean platelet volume (MPV) act as dynamic markers reflecting systemic inflammation, platelet consumption, marrow response, and platelet activation. Current prognostic tools, such as the SOFA and APACHE II/IV scores, provide important baseline risk stratification but are relatively static and may not fully capture the evolving host response to infection. Emerging evidence indicates that serial platelet indices yield greater prognostic information than single, baseline measurements. Furthermore, composite platelet-derived metrics-such as the MPV/PC ratio, platelet-to-lymphocyte ratio (PLR), CRP-to-platelet ratio (CRP/PLT), and platelet-to-creatinine ratio (PLT/Cr)-integrate signals of inflammation, haemostasis, and organ dysfunction, which may enhance clinical risk prediction. Despite these signals, few prospective studies have simultaneously examined the serial trajectories of PC and MPV, their derived ratios, and their incremental value beyond conventional severity scores. This prospective cohort study hypothesizes that serial PC and MPV dynamics, along with derived platelet ratios, independently predict in-hospital mortality in adults with sepsis after adjusting for clinical confounders. Demonstrating independent prognostic value and improved reclassification when these trajectory-based markers are combined with SOFA or APACHE scores would support incorporating routine, time-updated platelet indices into sepsis prognostication and risk-stratified management.