Clinical and economic burden of community-onset multidrug-resistant infections requiring hospitalization

Highlights

• Community-onset multidrug-resistant (MDR) infections are increasing.

• Clinical and economic burden of community-onset MDR infections were evaluated.

• Community-onset MDR infections had longer hospital stay and higher costs.

• Multidrug resistance was related to sicker patients and thus to worse outcomes.

• Multidrug resistance could be a marker of more complicated and expensive admissions.

Summary

Objectives

To analyze the clinical and economic burden of community-acquired (CA) or community-onset healthcare-associated (COHCA) multidrug-resistant (MDR) infections requiring hospitalization.

Methods

Case-control study. Adults admitted with CA or COHCA MDR infections were considered cases, while those admitted in the same period with non-MDR infections were controls. The matching criteria were source of infection and/or microorganism. Primary outcome was 30-day clinical failure. Secondary outcomes were 90-day and 1-year mortality, hospitalization costs and resource consumption.

Results

194 patients (97 cases and 97 controls) were included. Multivariate analysis identified age (odds ratio [OR], 1.07, 95% confidence interval [CI], 1.01–1.14) and SOFA score (OR, 1.45, CI95%, 1.15–1.84) as independent predictors of 30-day clinical failure. Age (hazard ratio [HR] 1.09, 95%CI, 1.03–1.16) was the only factor associated with 90-day mortality, whereas age (HR 1.06, 95%CI, 1.03–1.09) and Charlson Index (HR 1.2, 95%CI, 1.07–1.34) were associated with 1-year mortality. MDR group showed longer hospitalization (p<0.001) and MDR hospitalization costs almost doubled those in the non-MDR group. MDR infections were associated with higher antimicrobial costs.

Conclusions

Worse economic outcomes were identified with community-onset MDR infections. MDR was associated with worse clinical outcomes but mainly due to higher comorbidity of patients in MDR group, rather than multidrug resistance.

Introduction

Multidrug-resistant (MDR) bacterial infections have become a major public health concern over the last years, being associated with worse outcomes when compared with similar infections caused by susceptible strains.1, 2, 3, 4 They are closely related to delays to effective antibiotic treatment.^2,5 Furthermore, drugs that are active against MDR infections tend to be less effective and more toxic than conventional agents.² Patients with MDR infections are more prone to underlying conditions, which may lead to worse outcomes.^1,3 Antimicrobial resistance is also becoming a problem in terms of the functioning of healthcare systems and their budgets. A 2015 report estimated that G7 countries could face increased expenditure of about USD 2.9 trillion by 2050 because of MDR infections.⁶

MDR bacteria have traditionally been closely linked to hospital-acquired infections. In recent years however, the spread of these strains in the community has shifted problem beyond the hospital setting.⁷ Wolfe et al. pointed out that, in Japan, nearly one in three community-onset bloodstream infections was antibiotic-resistant.⁸ The increasing incidence of community-acquired infections due to Escherichia coli and extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae is especially concerning.^9,10 A Spanish national survey observed that approximately 32% and 10% of E. coli and ESBL-producing K. pneumoniae, respectively, could be considered community-onset infections.¹¹ Methicillin-Resistant Staphylococcus aureus (MRSA) is another example of the extensive spread of multidrug resistance beyond the hospital setting.¹² Although its prevalence has declined in most of Europe,¹³ community MRSA infections remain a healthcare problem, particularly since they usually combine resistance to other antimicrobial groups and can occur in healthy individuals without predisposing conditions.¹² Carbapenem-resistant bacteria are also an emerging threat with a reported prevalence ranging from 0.04% to 29.5% in community-acquired or community-onset infections.¹⁴

Previous studies have analyzed both the clinical and economic impact of multidrug resistance, although mainly in the context of hospital-acquired infections.15, 16, 17 In community-onset MDR infections however the burden of antibiotic resistance is not well understood. In addition, past research has mainly centered on specific MDR microorganisms or sources of infection,^5,10,18, 19, 20, 21, 22, 23 shifting the focus away from the global perspective of a global issue.

The aim of this study is to gain a better understanding of the clinical and economic impact of multidrug resistance in patients with community-onset MDR infections of any source caused by gram-positive or gram-negative MDR strains who require hospital admission.