Obesity paradox in HFrEF hospitalizations: analysis of national inpatient sample 2016-2018

Abstract

Funding Acknowledgements Type of funding sources: None. Introduction Obesity is a common and known risk factor for many cardiovascular diseases. Prior studies on chronic systolic heart failure have demonstrated that obesity is inversely associated with mortality, the so-called obesity paradox. Purpose To study the phenomenon of obesity paradox in HFrEF hospitalizations Methods We queried January 2016 to December 2018 National Inpatient Sample (NIS) to identify adult (≥18 yrs) hospitalizations with a primary diagnosis of HFrEF. Patients with an associated diagnosis of obesity and higher BMI were also identified based on appropriate ICD-10 CM codes. We used the Chi-square test to evaluate the differences between binary or categorical variables, and Student’s t-test for continuous variables. Multivariate logistic regression was used in outcomes analysis to adjust for potential hospital and patient-level confounders. Results We identified 639,944 weighted HFrEF hospitalizations across three years. Of which, 130,949 (20.4%) of them were associated with obesity. HFrEF with obesity hospitalizations were associated with younger age (mean age 62.0 vs 70.7 yrs; P < 0.01), lesser CAD (55% vs 61%; P < 0.01), higher rate of comorbidity (% of >3 Elixhauser comorbidity score 99.2% vs 94.1%; P < 0.01) and higher Medicaid primary payer (18.2% vs 12.7%, P < 0.01). After adjusting for patient and hospital-level characteristics, we observe statistically significant difference in odds of in-hospital mortality when HFrEF with obesity hospitalizations was compared to HFrEF without obesity [Odds Ratio (OR): 1.1 (0.8 – 1.5); P = 0.52]. We observed statistically significant association with increased LOS [6.0 vs 5.3 days; P < 0.01], increased total hospitalization charges [US$ 61524 vs 55677; P < 0.01] and decreased coronary catheterizations [OR: 0.7 (0.5 – 0.9); P = 0.01] in HFrEF with obesity group compared to HFrEF without obesity. Conclusion In this retrospective cohort of hospitalized patients with HFrEF, higher BMI and obesity was not associated with in-hospital mortality. However, it was associated with longer LOS and higher total hospitalization charges. HFrEF with obesity hospitalizations are associated with lesser left coronary catheterizations. This may be explained by lesser burden of CAD in this patient population.