Platelet counts and prognosis in heart failure with mildly reduced ejection fraction: results from a large-scale registry

Abstract Objective Platelets have been reported to promote heart failure (HF) through prothrombotic and proinflammatory pathways. The present study sought to investigate the prognostic impact of baseline platelet counts in patients hospitalized with heart failure with mildly reduced ejection fraction (HFmrEF). Background The association of platelet count and prognosis in patients with HFmrEF is not well studied. Methods Consecutive patients with HFmrEF (ie, left ventricular ejection fraction 41–49% and signs and/or symptoms of HF) were retrospectively included at one institution from 2016 to 2022. Clinical outcome was assessed according to platelet count quintiles (50/nL, 50-100/nL, 100-150/nL, 150-450/nL, and 450/nL): the primary endpoint was all-cause mortality at 30 months (median follow-up). The key secondary endpoint was HF-related rehospitalization at 30 months. Results From a total of 2,151 consecutive patients with HFmrEF, the median platelet count was 253/nL (interquartile range (IQR) 196-287/nL). A baseline platelet count 50/nL (HR = 3.487; 95% CI 2.111-5.760; p = 0.001) and 50-100/nL (HR = 1.565; 95% CI 1.024-2.394; p = 0.036) was associated with increased risk of 30-months all-cause mortality compared to patients with normal platelet counts, which was still demonstrated after multivariable adjustment. In contrast, the presence of increased platelet count (450/nL) was not associated with long-term all-cause mortality (HR = 1.140; 95% CI 0.769 – 1.690; p = 0.515). Furthermore, no association between platelet count and the risk of HF-related rehospitalization was observed. Conclusion In patients hospitalized with HFmrEF, platelet counts of 50/nL and 50-100/nL were independently associated with an increased risk of all-cause mortality at 30 months.