Impact of Thrombocytopenia on the Outcomes of Patients Admitted With Heart Failure: Analysis of the National Inpatient Sample

Background: Thrombocytopenia is known to be a marker of adverse clinical outcomes in acute coronary syndromes, pulmonary hypertension and critically ill patients. Its impact on heart failure (HF) patients has not been well characterized. We aim to compare the clinical outcomes in patients admitted for HF with and without thrombocytopenia. Methods: A retrospective cohort study was designed using data obtained from the 2016-2019 National Inpatient Sample (NIS) database. Adult patients (age >18) with a principal diagnosis of Heart Failure (HF) were identified using the International Classification of Diseases code, tenth revision (ICD-10), and were divided into two cohorts based on a secondary diagnosis of Thrombocytopenia. Primary outcomes evaluated were in-patient mortality, Length Of Stay (LOS) and Total Hospitalization Charges(THC). Secondary outcomes included a blood transfusion, AKI, Pneumonia, Sepsis and GI bleed. Results: Out of 1,276,429 adult patients admitted with HF, 70,755 (5.5%) were found to have a diagnosis of thrombocytopenia. The mean age was 72 years for the thrombocytopenia group vs 71 years for the other group. On a multivariate regression analysis after adjusting for confounders, HF patients with thrombocytopenia had double the odds of inpatient mortality (aOR 2.0 , 95% CI 1.84-52.16, p<0.01) and LOS (aOR 2.38 , 95% CI 2.19-2.58 p<0.01) compared to the other group .THC was also increased by 43,376$ ( 95%CI 38,842-47,910 ,p<0.01). Among the secondary outcomes, the rate of blood transfusion (6.4% vs 2.1%, aOR 2.19, 95% CI 2.02-2.38, p<0.01), AKI (37.4% vs 25.0%, aOR 1.5, 95% CI 1.44-1.56, p<0.01), Pneumonia (16% vs 13%, aOR 1.18, 95% CI 1.12-1.25, p<0.01),Sepsis (3.08% vs 1.13, aOR 2.5 ,95% CI 2.22-2.78, p<0.01) and GI Bleed (0.9 %vs 0.4 %, aOR 1.68, 95% CI 1.38-2.05, p<0.01) was also significantly elevated in the thrombocytopenia group. Conclusion: HF patients with thrombocytopenia had worse clinical outcomes compared to those without. Very few studies have explored this impact of thrombocytopenia on HF and concluded with similar outcomes, probably related to abnormal platelet activity in this population and its consequence on cardiac function. This finding highlights the need for future studies to elucidate the pathophysiology and include platelet level in prognostic tools.