Antibacterial drug use in hospitalised patients with COVID-19 during successive epidemic waves in Hong Kong

Abstract

<h1>Background</h1><p>Hong Kong experienced four small epidemic waves (1-4) caused by the ancestral strain of SARS-CoV-2 in 2020-2021 and two Omicron waves (5 and 6) in 2022. Antibacterial drugs are widely prescribed to patients hospitalized with COVID-19,[1, 2] yet quantifying their use and determining factors associated with their prescription, especially during recent Omicron waves, has not been assessed.</p><h1>Methods</h1><p>We calculated the prevalence and rates (days of therapy (DOT)/1000 patient-days) of antibacterial use in patients admitted to all public hospitals with community-acquired SARS-CoV-2 infections in Hong Kong from 21 January 2020 to 30 September 2022. All inpatient prescriptions for drugs classified in BNF Section 5.1: Antibacterial drugs were included and were further grouped according to the WHO AWaRe classification. Binary logistic regression was used to assess the association between baseline patient characteristics and disease severity and an inpatient antibacterial prescription.</p><h1>Results</h1><p>We included 65,810 locally-acquired cases. The overall prevalence of antibacterial use was 54.0% and was lowest in the 4^th wave, then more than doubled in the 5^th wave (Table). Older age, more severe disease, and being admitted from a residential home for the elderly were associated with higher odds of inpatient antibacterial prescription. In contrast, admission during waves 3, 4, or 6, >1 dose of COVID-19 vaccination, and coronavirus specific antiviral treatments were associated with lower odds (Fig. 1). Rates of antibacterial use ranged from 246.9 DOT/1000 patient-days in waves 1-2 to 661.2 DOT/1000 patient-days in wave 5, which also had the greatest rates of Watch and Not Recommended antibiotic use (Fig. 2). Three antibiotics accounted for 67.9% of all DOT: amoxicillin/clavulanic acid (38.9%), piperacillin/tazobactam (16.3%) and ceftriaxone (12.7%). The percentage of total antibacterial DOT were 47.8% for Access, 49.5% for Watch, 0.9% for Reserve and 1.8% for Not Recommended antibiotics.</p><h1>Conclusions</h1><p>The highest rates of antibacterial drug use occurred during the 5^th wave of COVID-19 epidemic which had a rapid increase in hospital admissions for older adults and more severe cases. Reducing the risk of severe disease through vaccination and early treatment with targeted antiviral drugs should contribute to reduced inpatient antibiotic use as demonstrated by lower use in the 6^th wave.<br></p>