Prognostic impact of platelet count trajectories in acute decompensated heart failure: a retrospective cohort analysis

AIMS: To determine whether in-hospital platelet count trajectories during admission for acute decompensated heart failure (ADHF) are associated with early and longer-term outcomes after discharge. METHODS: We performed a single-centre retrospective cohort study of adults hospitalized for ADHF (2007-2017). After excluding in-hospital deaths and cases without paired platelet measurements, 6,789 patients were analyzed from an initial 8,332. Platelet status was defined by WHO thresholds at admission and discharge and categorized into four trajectories: Normal→Normal (n = 5,453), Low→Low (n = 700), Normal→Low (n = 325), and Low→Normal (n = 311). Outcomes from the date of discharge were: 30-day readmission and 30-day mortality (binary), and time-to-event 1-year readmission and 1-year and 5-year all-cause mortality. Multivariable logistic regression modeled 30-day endpoints; Cox models estimated hazard ratios (HRs) for 1- and 5-year outcomes, adjusting for prespecified clinical covariates. A multinomial-propensity-score inverse probability weighting sensitivity analysis assessed robustness. RESULTS: Relative to the Normal→Normal group, the Normal→Low trajectory (normal platelets on admission, thrombocytopenia at discharge) was associated with higher 30-day readmission (OR 1.39, 95% CI 1.08-1.80, p = 0.011) and markedly higher 30-day mortality (OR 2.40, 95% CI 1.58-3.63, p < 0.001). It was also associated with higher 1-year mortality (HR 1.66, 95% CI 1.37-2.02, p < 0.001) and 5-year mortality (HR 1.37, 95% CI 1.21-1.56, p < 0.001), while 1-year readmission did not differ significantly. The Low→Low trajectory showed no association with 5-year mortality (HR 1.05, 95% CI 0.95-1.15, p = 0.332), and Low→Normal trended toward lower 5-year mortality (HR 0.88, 95% CI 0.77-1.01, p = 0.061). Findings were directionally consistent in inverse-probability-weighted analyses. CONCLUSIONS: In patients hospitalized with ADHF and discharged alive, a decline in platelet count from normal at admission to thrombocytopenia at discharge was associated with excess 30-day readmission and mortality and with persistent excess mortality at 1 and 5 years after discharge. The incremental discrimination over established clinical covariates was modest, indicating that platelet trajectory is unlikely to serve as a standalone risk tool. Because platelet counts are inexpensive and routinely available, the in-hospital trajectory warrants further evaluation as a candidate prognostic adjunct to established HF risk frameworks, pending prospective external validation.