Introduction

Prompt and accurate pathogen identification is crucial for treatment of severe sepsis and septic shock (SS/SS). Blood cultures (BC) require 24 to 48 hours and often yield inaccurate results. Effective pathogen identification allows for timely, targeted antimicrobial therapy.

Methods

A SS/SS Markov model [1] was developed to assess the cost-effectiveness (CE) of a rapid and accurate diagnostic test compared with the current standard. In the model, patients can transition between no SIRS, SIRS, sepsis, severe sepsis and septic shock or exit the model via discharge or death. Key literature assumptions are as follows: 91% effectiveness of empiric therapy, 70% BC effectiveness, 90% new test effectiveness, $750 cost/test, 9.5 years average life expectancy of sepsis survivor, 0.69 quality-adjusted life-year (QALY) for survivors, and turnaround times of 24 hours for the new test and 48 hours for standard BC.

Results

The model shows that the new test would be cost-effective when compared with current BC, at a cost of $32,939 per QALY (day 28). These results are compelling across a range of assumptions and almost all estimates fall below the US CE threshold of $50,000 to $100,000/QALY (Figure 1). Varying most assumed values by up to 25% had a moderate impact on CE. CE is sensitive to empiric test effectiveness >95%. More rapid diagnostic information lowered the cost/QALY.

Figure 1
figure 1

Sensitivity analysis on CE (Base Case CE = $32,939/QALY).

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Conclusions

Preliminary results show that a rapid and accurate test would be considered cost-effective across many assumptions and would reduce the mortality associated with delayed diagnosis.