Background: It is uncertain whether antibiotic therapy should be started in SARS CoV-2 pneumonia. We aimed to investigate the association between early antibiotic therapy and the risk of in-hospital mortality in older patients.

Methods: We performed a retrospective international cohort study (ANTIBIOVID) in five COVID-19 geriatric units in France and Switzerland. Among 1,357 consecutive patients aged 75 or more hospitalised and testing positive for SARS-CoV-2, 1072 had a radiologically confirmed pneumonia, of which 914 patients were still alive and hospitalized at 48 hours. To adjust for confounders, a propensity score for treatment was created, and stabilized inverse probability of treatment weighting (SIPTW) was applied. To assess the association between early antibiotic therapy and in-hospital 30-day mortality, SIPTW-adjusted Kaplan-Meier and Cox proportional hazards regression analyses were performed.

Results: Of the 914 patients with SARS-CoV-2 pneumonia, median age of 86, 428 (46.8%) received antibiotics in the first 48 hours after diagnosis. Among these patients, 147 (34.3%) died in hospital within one month vs 118 patients (24.3%) with no early antibiotic treatment. After SIPTW, early antibiotic treatment was not significantly associated with mortality (adjusted hazard ratio, 1.23; 95% CI, 0.92-1.63; P = .160). Microbiologically confirmed superinfections occurred rarely in both groups (bacterial pneumonia: 2.5% vs 1.5%, P = .220; blood stream infection: 8.2% vs 5.2%, P = .120; Clostridioides difficile colitis: 2.4% vs 1.0%, P = .222).

Conclusions: In a large multicentre cohort of older inpatients with SARS-CoV-2 pneumonia, early antibiotic treatment did not appear to be associated with an improved prognosis.