Clinical and Economic Burden of Multidrug-Resistant Infections in Critically Ill Patients: Impact On ICU Mortality, Length of Stay, and Healthcare Resource Utilization—A Prospective Observational Study

Background: Multidrug resistance (MDR) has become a significant problem in intensive care units (ICUs), where it results in mortality, longer hospital stays and unnecessary use of health care resources. The goal of this study was to assess the effects of MDR infections on clinical outcomes and/resources utilization in critically ill patients.

Materials and methods: A prospective observational study of 300 adult-ICU patients with microbiologically confirmed bacterial infection were performed. Patients were classified into two groups, MDR (n=118) and non-MDR (n=182) groups, according to ASB. Demographic and clinical parameters, microbiological results, utilization of health services and clinical outcomes were documented. Multivariable logistic regression analysis was carried out to determine independent predictors of ICU mortality.

Results: MDR infections were detected in 39.3% of patients. The most frequently reported infection source was ventilator-associated pneumonia (VAP), and MDR pathogen species most often reported was carbapenem-resistant Acinetobacter baumannii. The mortality rate at ICU was significantly higher for MDR infections than non-MDR infections (41.5% vs 19.8%, p<0.001). MDR-infected patients also experienced higher rates of septic shock (45.8% vs. 24.2%), acute kidney injury (39.8% vs. 23.6%), mechanical ventilation (77.1% vs. 56.6%), and vasopressor use (70.3% vs. 48.9%) (all p<0.05). The population of the MDR group was significantly associated with greater healthcare resource use such as longer days in the ICU (15.4±8.1 vs. 8.7±5.2 days, p<0.001); longer hospitalisation; higher antibiotic use, and higher treatment costs (all p<0.001). MDR infection was an independent risk factor for ICU mortality (adjusted OR 2.84, 95% CI 1.67–4.82, p<0.001) in multivariable analyses.

Conclusion: MDR infections make the clinical outcome of critically ill more severe and the use of healthcare resources more expensive. Improved antimicrobial stewardship, infection prevention, and prompt early pathogen-directed therapy can counter the trend of increasing numbers of MDR infections in ICUs.

Keywords: Multidrug-resistant infections, Intensive care unit, ICU mortality, Antimicrobial resistance, Healthcare resource utilization, Length of stay, Critical care, Carbapenem resistance.