OBJECTIVES: This study aims to investigate the implications of influenza on patients with congestive heart failure (CHF) over ten years (2010-2020), excluding 2015, utilizing the national readmission database.

METHODS: A comprehensive analysis was conducted on a substantial patient cohort of 19,161,164 discharges, categorized into sub-cohorts based on the presence or absence of influenza during admissions. The total number of unweighted discharges over ten years (excluding 2015) were 158,190,285. In these unweighted discharges, there were 150,120 (0.78%) of patients with influenza, and 19,011,044 (99.22%) of patients without influenza.

RESULTS: Baseline characteristics of index admissions revealed significant differences in demographic factors, including sex and age groups, as well as length of stay (LOS), primary expected payer/insurance, and calendar year distribution. A detailed exploration of comorbidities reveals notable variations between the influenza and non-influenza cohorts, with conditions like myocardial infarction (21.68% vs. 21.32%, p<0.001), dementia (9.99% vs. 7.33%, p<0.001), COPD (51.88% vs. 42.50%, p< 0.001), Rheumatoid Disease (4.42% vs. 3.66%, p<0.001), and Diabetes with chronic complications (23.31% vs. 20.67%, p<0.001) showing significant disparities. The CCI analysis indicates a noteworthy difference, with a higher proportion of patients in the influenza cohort having a CCI≥4, suggesting a greater burden of comorbid conditions. Mortality during the index hospitalization is found to be higher in the influenza cohort (6.29% vs. 5.38%, p<0.001), emphasizing the potential impact of influenza on the severity of heart failure. Additionally, subtle variations in readmission rates within 30 days across calendar years are observed.

CONCLUSIONS: These findings underscore the critical importance of recognizing influenza as a potential exacerbating factor in CHF patients. The study highlights the need for targeted preventive strategies and nuanced management approaches to address the unique challenges faced by this vulnerable population.