biostudies-literaturePaules CINHLBI NIH HHSNational Institutes of HealthNIH HHS67https://www.ebi.ac.uk/biostudies/studies/S-EPMC11734232biostudies-literatureUnknown25(1)<h4>Background</h4>Low blood absolute lymphocyte count (ALC) may predict severe COVID-19 outcomes. Knowledge gaps remain regarding the relationship of ALC trajectory with clinical outcomes and factors associated with lymphopenia.<h4>Methods</h4>Our post hoc analysis of the Therapeutics for Inpatients with COVID-19 platform trial utilized proportional hazards models to assess relationships between Day (D) 0 lymphopenia (ALC < 0.9 cells/uL), D0 severe lymphopenia (ALC < 0.5 cells/uL) or lymphopenia trajectory between D0 and D5 with mortality and secondary infections, and with sustained recovery using Fine-Gray models. Logistic regression was used to assess relationships between clinical variables and D0 lymphopenia or lymphopenia trajectory.<h4>Results</h4>D0 lymphopenia (1426/2579) and seveBMC infectious diseasesBlood absolute lymphocyte count and trajectory are important in understanding severe COVID-19.PMC117342321OT2HL156812-01OT2 HL156812Aberg JALundgren JGardner EMVasudeva SGoodman ALAggarwal NRPaules CIVock DMShaw-Saliba KNorth CMKumarasamy NSTRIVE Network and TICO Trial Study GroupNordwall JAfalseBlood absolute lymphocyte count and trajectory are important in understanding severe COVID-19.<h4>Background</h4>Low blood absolute lymphocyte count (ALC) may predict severe COVID-19 outcomes. Knowledge gaps remain regarding the relationship of ALC trajectory with clinical outcomes and factors associated with lymphopenia.<h4>Methods</h4>Our post hoc analysis of the Therapeutics for Inpatients with COVID-19 platform trial utilized proportional hazards models to assess relationships between Day (D) 0 lymphopenia (ALC < 0.9 cells/uL), D0 severe lymphopenia (ALC < 0.5 cells/uL) or lymphopenia trajectory between D0 and D5 with mortality and secondary infections, and with sustained recovery using Fine-Gray models. Logistic regression was used to assess relationships between clinical variables and D0 lymphopenia or lymphopenia trajectory.<h4>Results</h4>D0 lymphopenia (1426/2579) and seve2025-01-01T00:00:00Z2025 Jan2026-05-02T14:31:31.673Z2025-04-06T01:15:04.806ZS-EPMC117342323981007710.1186/s12879-024-10428-7