Compared to culture/sensitivity results (C/S) results, ICU-based PCR testing of hospital-acquired pneumonia was associated with lower treatment costs and better antibiotic stewardship, but not higher cure rates.
Rapid multiplex polymerase chain reaction (PCR) testing of hospital-associated and ventilator-acquired pneumonia in the ICU was found to improve antimicrobial stewardship and lower total treatment costs compared to treatment guided by culture/sensitivity results,1 but with only comparable rates of cure.2
The investigators note that routine characterization of the pathogens in hospital-acquired pneumonia (HAP, onset >48 hours after admission) and ventilator-associated pneumonia (VAP, onset >48 hours after endotracheal intubation) takes 48 to 72 hours with culture and sensitivity (C/S) testing. Treatment usually begins with broad-spectrum empirical antibiotics, and the regimen is refined after C/S results are available.
"PCR tests can expedite this process, as well as offering improved sensitivity," explain Adam Wagner, PhD, MSc, Norwich Medical School, University of East Anglia, Norwich, UK, and colleagues."In principle, these faster, more accurate results might improve patient treatment and outcomes.They may also facilitate improved antibiotic stewardship."
Rapid PCR testing is limited in range of pathogens and resistances, however, so the cost of its implementation in the ICU is in addition to, rather than instead of cost for microbiology capabilities.As the investigators had previously determined that PCR testing was non-inferior but not superior to C/S in facilitating clinical cure of pneumonia at 14 days, this cost-effectiveness study focused on distinguishing the testing methods by impact on total treatment costs and antibiotic stewardship.
Wagner and colleagues revisited data from the INHALE WP3 trial, a randomized controlled trial conducted across 14 ICUs (11 adult and 3 pediatric) in 13 hospitals in the period between July 2019 through August 2021 (with pause in recruitment for the COVID-19 pandemic between March and July 2020).From the cohort of patients about to receive initial empiric antibiotics for HAP or VAP, 268 patients were randomized to receive ICU-based PCR testing and 265 to treatment as usual, guided by C/S.
The two economic outcome measures were: extra cost per additional person on active and proportionate antibiotic therapy within 24h of clinical diagnosis (related to stewardship); and cost per additional clinical cure of pneumonia at 14 days post-randomization.In addition, the study sought to determine superiority in antibiotic stewardship by the proportion of patients on active and proportionate antibiotic therapy within 24 hours of clinical diagnosis. The investigators defined antibiotic therapy "active" if confirmed in-vitro against the target pathogen, and "proportionate" if not "excessively broad-spectrum" for the pathogen(s) identified.
Rapid ICU-based PCR testing for HAP/VAP led to faster initiation of appropriate, proportionate antibiotics and reduced overall ICU costs compared with culture-based management.
While PCR improved stewardship, it was not superior to culture/sensitivity testing in achieving clinical cure at 14 days.
The primary cost savings came from shorter or more efficient ICU resource use, which outweighed the added expense of PCR testing itself.
Wagner and colleagues reported lower total ICU costs (including for PCR) with the ICU-based PCR intervention: ₤33,149 ($44,609 USD) average compared to ₤40,951 ($55,113 USD) with standard of care.
"For antibiotic stewardship, the PCR-guided therapy was both less costly and more effective than routine patient management," they indicated. They also noted that PCR-guided therapy was not determined to be cost-effective for clinical cure "due to fewer cases being cured in the intervention group."
"We found, as expected, that the most impactful item of resource use was the cost of ICU stays, and that differences in this item far exceeded the unit cost of the Pneumonia Panel, and to a lesser extent, antimicrobial therapy costs," Wagner and colleagues concluded.
