# Nationwide Analysis (2016-2020) of the Burden of Thrombocytopenia on Patients Admitted Due to Myocardial Infarction, Heart Failure or Atrial Fibrillation

## TL;DR

This study shows that low platelet count (thrombocytopenia) in patients hospitalized for heart conditions like heart attack, heart failure, or atrial fibrillation is linked to higher death rates, longer hospital stays, and more resources used.

## Contribution

The study is the first nationwide analysis linking thrombocytopenia to adverse outcomes in patients with MI, HF, or AF.

## Key findings

- Thrombocytopenia was associated with significantly higher in-hospital mortality across all three patient groups.
- Hospital stays were longer and resource use higher for patients with thrombocytopenia.
- The need for intubation was increased in patients with thrombocytopenia.

## Abstract

Background: Myocardial infarction (MI), heart failure (HF) exacerbation, and atrial fibrillation/atrial flutter (AF) affect millions of patients every year, and thrombocytopenia is a common laboratory finding in hospitalized patients. This study aimed to investigate the impact of thrombocytopenia in patients admitted due to MI, HF, or AF in terms of mortality, length of stay, resource utilization, and need for intubation.

Methods: This is a National Inpatient Sample Database analysis from 2016-2020. Patients admitted with a primary diagnosis of MI, HF, or AF, with or without a secondary diagnosis of thrombocytopenia, were identified using ICD-10-CM codes. The primary outcome of our analysis was mortality. Secondary outcomes included length of stay, resource utilization, and necessity for endotracheal intubation. Univariate analysis was done for hospital-level and patient baseline characteristics such as age, gender, race, Charlson comorbidity index, insurance, hospital location, size, region, and teaching status. Baseline characteristics with p-value < 0.2 were considered significant and were adjusted in a multivariate analysis. Data was statistically significant if p-value <0.05.

Results: Among 3,093,479 patients who had a primary diagnosis of MI between 2016 and 2020, 5.13% (N=158,755) had thrombocytopenia. Among 1,187,164 patients who had a primary diagnosis of HF exacerbation, 5.92% (N=70,225) had thrombocytopenia. Of the 2,292,194 patients admitted due to AF, 3.53% (N=80,935) also had thrombocytopenia. Overall, outcomes were poor for all groups. Adjusted outcomes showed that in-hospital mortality was significantly higher in thrombocytopenic patients of all three groups: MI (OR 1.82; 95% CI 1.73 - 1.91; p<0.001), HF exacerbation (OR 2.13; 95% CI 1.96 - 2.32; p<0.001), AF (OR 2.29; 95% CI 2.02 - 2.6; p<0.001). Length of stay was significantly longer in thrombocytopenic patients of all three groups: MI (Regression coefficient 3.65; 95% CI 3.53 - 3.76; p<0.001), HF (Regression coefficient 2.39; 95% CI 2.19 - 2.59; p<0.001), AF (Regression coefficient 1.35; 95% CI 1.26 - 1.45; p<0.001). Resource utilization was significantly higher in thrombocytopenic patients of all three groups: MI (Regression coefficient 80,272.54; 95% CI 76,853.92 - 83,691.16; p<0.001), HF (Regression coefficient 40,802.52; 95% CI 36,367.31 - 45,237.74; p<0.001), AF (Regression coefficient 15,330.34; 95% CI 13,579.82 - 17,080.86; p<0.001). The need for endotracheal intubation was also increased in thrombocytopenic patients of all three groups: MI (OR 2.39; 95% CI 2.28 - 2.5; p<0.001), HF (OR 2.51; 95% CI 2.26 - 2.79; p<0.001), and AF (OR 2.88; 95% CI 2.53 - 3.28; p<0.001).

Conclusion: Thrombocytopenia has substantial negative outcomes in hospitalized patients with MI, HF, or AF. Thrombocytopenia could be a marker of poor prognosis, and greater awareness among physicians could potentially guide patient risk stratification, treatment decisions, resource allocation, and patient/ family counseling during hospitalization.