Impact of low-dose chest computed tomography and multiplex PCR on antibiotic usage for community-acquired pneumonia: multicentre prospective controlled before–after study with cluster randomization

OBJECTIVES: We investigated if low-dose chest computed tomography (CT) or multiplex point-of-care PCR (PoC-PCR) for respiratory pathogens can safely reduce broad-spectrum antibiotic use in patients with moderate-to-severe community-acquired pneumonia (CAP). METHODS: Multicentre prospective controlled before-after study with cluster randomization. Randomization was stratified by implementation feasibility. Five teaching, one nonteaching, and one university hospital in the Netherlands. Adults with initial diagnosis of CAP requiring admission to nonintensive care unit ward. Low-dose CT or PoC-PCR implemented in routine care with antibiotic treatment recommendations compared with standard care. Superiority of days on therapy with broad-spectrum antibiotics and noninferiority of all-cause 90-day mortality based on intention-to-treat. RESULTS: The study was started in December 2017 and terminated prematurely in March 2020 because of substantial changes in routine diagnostic practice for CAP during the COVID-19 pandemic. After the baseline period (2245 patients), 561 patients were included in the low-dose CT group (two hospitals), 910 in the PoC-PCR group (two hospitals), and 2084 in standard care (three hospitals). All included patients were analysed. CT was performed in 40% of patients in the low-dose CT group, and PCR testing was done in 67% in the PoC-PCR group. Compared with standard care, the adjusted relative risk on days on therapy broad-spectrum antibiotics was 1.12 (95% CI 0.90-1.38) for low-dose CT and 0.89 (95% CI 0.75-1.04) for PoC-PCR. Noninferiority was demonstrated for PoC-PCR but not for low-dose CT. CONCLUSIONS: In patients with moderate-to-severe CAP, it is unlikely that low-dose chest CT impacts broad-spectrum antibiotic treatment, whereas a relevant effect could not be demonstrated nor excluded for PoC-PCR. Trial registration at clinicaltrials.gov (NCT03360851).