Evaluating the cost-effectiveness of rapid diagnostic testing for the identification of pathogens and resistance genes in bloodstream infections

Objectives

Bloodstream infections (BSI) are a leading cause of mortality worldwide. Rapid detection of the causative pathogen can help optimise therapy, reduce mortality, curb antimicrobial resistance, and lower healthcare costs. This study evaluates the cost-effectiveness of adding molecular rapid diagnostic tests (mRDTs) to microbiology standard-of-care (SoC) methods. mRDTs evaluated include the Cobas ^® Eplex blood culture identification (BCID) panels, BioFire ^® BCID panel, BioFire ^® BCID2 panel, Accelerate PhenoTest ^™ blood culture (BC) kit and Diasorin Verigene ^® BCID panels.

Methods

A decision-tree model was built to quantify the incremental costs and outcomes associated with adding mRDTs to the SoC. The inputs were derived from the published literature. The analysis considered a population aged 65 years and 45% female, admitted to a United States (US) hospital with a suspected BSI. Model outcomes included costs, 30-day mortality, quality-adjusted life years (QALYs) and adverse events ( Clostridioides difficile infection and acute kidney injury [AKI]). A United Kingdom (UK) setting in place of the US setting was also considered in the scenario analysis.

Results

A strategy involving the Cobas Eplex BCID panels as an adjunct test to the SoC dominated SoC alone without Cobas Eplex BCID panels, saving $164 per patient and averting 24 deaths per 10,000 patients. Earlier optimisation of ineffective empiric therapy generated half of the lives saved, with the majority of the remainder from reductions in AKI. This strategy was also dominant compared with other mRDTs. In a UK setting, Cobas Eplex BCID panels remained cost-effective, saving £51 compared with SoC. Results were robust to scenarios varying key model inputs including time to pathogen identification with SoC.

Conclusions

The model demonstrated improved patient survival and reduced average total costs with mRDT. The Cobas Eplex BCID panels, which has the largest pathogen coverage, reduced both mortality and overall costs compared with other mRDTs.

Key points for decision makers

• Rapid identification of BSI pathogens enables early optimisation of antimicrobial therapy, which can improve patient outcomes, reduce healthcare costs, and mitigate antimicrobial resistance. Conventional methods, including culture followed by MALDI-ToF MS, are time intensive. In contrast, mRDTs can identify pathogens within hours, facilitating earlier treatment optimisation.

• Evidence on the cost-effectiveness of mRDTs is limited, despite their potential to reduce overall costs by reducing length of stay (LOS). This study provides a comprehensive assessment of the cost-effectiveness of adding mRDTs to SoC.

• Cost savings from reductions in LOS and adverse events arising from broad-spectrum antimicrobial therapy are more than sufficient to offset the cost of procuring the mRDTs. Hence the use of mRDTs improves patient outcomes and contributes to antibiotic stewardship, alongside lowering costs.

• The Cobas Eplex BCID panels, with broadest coverage of pathogens, dominated other mRDTs.

Plain Language Summary

Bloodstream infections (BSI) are responsible for significant morbidity and mortality, causing 250,000 deaths each year in Europe and the United States (US) [1]. Rapid treatment with an effective antimicrobial is potentially one of the most important elements of care for patients with BSI, and patients are typically treated with two broad-spectrum antimicrobials rapidly (within an hour) if BSI is suspected. Conventional methods to identify the cause of the BSI require culturation of blood culture bottles followed by Gram stain and sub-culture onto solid agar plates to isolate individual colonies. Molecular rapid diagnostic tests (mRDTs) allow detection of a range of different pathogens causing BSIs within a few hours of a blood culture bottle flagging positive [2]. These tests offer the potential to improve care by reducing time to appropriate therapy which in turn can save lives and lower costs. This analysis used a decision-tree model to evaluate the costs and benefits of adding mRDTs to conventional methods. The study finds that mRDTs save lives and generate lower overall costs compared with standard of care (SoC) methods alone. Among the mRDTs, the Cobas ^® Eplex BCID panels, which detect the broadest spectrum of pathogens, were associated with the highest reduction in mortality and overall costs compared with other mRDTs.

Declarations