Mortality, Length of Stay, and Healthcare Costs Associated With Multidrug-Resistant Bacterial Infections Among Elderly Hospitalized Patients in the United States

Abstract

Background: This study reports estimates of the healthcare costs, length of stay, and mortality associated with infections due to multidrug-resistant bacteria among elderly individuals in the United States.

Methods: We conducted a retrospective cohort analysis of patients aged ≥65 admitted for inpatient stays in the Department of Veterans Affairs healthcare system between 1/2007-12/2018. We identified those with positive cultures for multidrug-resistant bacteria and matched each infected patient to ≤10 control patients. We then performed multivariable regression models to estimate the attributable cost and mortality due to the infection. We also constructed multistate models to estimate the attributable length of stay due to the infection. Finally, we multiplied these pathogen-specific attributable cost, length of stay, and mortality estimates by national case counts from hospitalized patients in 2017.

Results: Our cohort consisted of 87 509 patients with infections and 835 048 matched controls. Costs were higher for hospital-onset invasive infections, with attributable costs ranging from $22 293 (95% confidence interval: $19 101-$24 485) for methicillin-resistant Staphylococcus aureus (MRSA) to $57 390 ($34 070-$80 710) for carbapenem-resistant (CR) Acinetobacter. Similarly, for hospital-onset invasive infections, attributable mortality estimates ranged from 14.2% (12.2-16.2%) for MRSA to 24.1% (12.1-36.0%) for CR Acinetobacter. The aggregate cost of these infections was an estimated $1.9 billion ($1.3 billion-$2.5 billion) with 11 852 (8719-14 985) deaths and 448 224 (354 513-541 934) inpatient days in 2017.

Conclusions: Efforts to prevent these infections due to multidrug-resistant bacteria could save a significant number of lives and healthcare resources.

Keywords: antimicrobial resistance; healthcare-associated infections; mortality; veterans.

Figure 1.

Unadjusted mean hospital costs per patient by pathogen type and onset. Abbreviations: CR, carbapenem-resistant; CRE, carbapenem-resistant Enterobacteriaceae; ESBL, extended-spectrum β-lactamase; MDR, multidrug-resistant; MRSA, methicillin-resistant Staphylococcus aureus; VRE, vancomycin-resistant Enterococcus.

Figure 2.

Unadjusted 30-day probability of mortality by pathogen type and onset. Abbreviations: CR, carbapenem-resistant; CRE, carbapenem-resistant Enterobacteriaceae; ESBL, extended-spectrum β-lactamase; MDR, multidrug-resistant; MRSA, methicillin-resistant Staphylococcus aureus; VRE, vancomycin-resistant Enterococcus.