The Burden of Heart Failure and Its Impact on Mortality and Outcomes in Hospitalized Multiple Myeloma Patients: A Nationwide Study.

Background Multiple myeloma is a hematologic malignancy characterized by its association with a range of cardiovascular comorbidities, most notably heart failure. Our study aims to investigate the impact of heart failure on individuals who are hospitalized for multiple myeloma. Methods In this retrospective cohort study, we assembled a cohort of patients diagnosed with multiple myeloma from the National Inpatient Sample (NIS) data from 2019 to 2020. Within this study population, patients were classified according to the presence or absence of heart failure as a secondary diagnosis, with further stratification into distinct groups such as heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). The primary outcome studied was inpatient mortality. Secondary outcomes were length of stay, total hospitalization charges, acute respiratory failure, acute kidney injury, intensive care unit (ICU) admission, and mechanical ventilation. Confounders were adjusted using multivariate regression analysis. Results Among the 38,735 patients admitted with multiple myeloma, 5.6% (2,195 patients) were diagnosed with HFpEF, while 3% (1,170 patients) had HFrEF. The mortality rate was significantly higher in HFpEF patients compared to HFrEF and non-heart failure individuals (aOR: 1.68, [CI: 1.17-2.43]; P = 0.005). Length of hospital stay did not differ between these two groups; however, total hospitalization charges were more significant in the presence of heart failure versus without heart failure (coefficient: 33597; CI: 1730-65463; P = 0.04; and coefficient: 26107; CI: 5414-46800; P = 0.01 for HFrEF and HFpEF, respectively). Similarly, a significant increase in the odds of acute respiratory failure, care at the ICU, and requirement for mechanical ventilation was observed in patients with both types of heart failure compared to those without heart failure. Conclusion HFpEF was associated with high mortality rates and greater incidence of acute kidney injury in multiple myeloma patients compared to those with HFrEF and non-heart failure counterparts. However, both heart failure subtypes were associated with heightened total hospitalization charges and the increased likelihood of encountering acute respiratory failure, admission to the ICU, and the utilization of mechanical ventilation compared to patients without heart failure.