Inpatient Antibacterial Drug Prescribing for Patients with COVID-19 in Hong Kong

BackgroundHong Kong experienced four epidemic waves caused by the ancestral strain of SARS-CoV-2 in 2020-2021 and a large Omicron wave in 2022. Few studies have assessed antibacterial drug prescribing for COVID-19 inpatients throughout the pandemic. ObjectivesTo describe inpatient antibacterial drug prescribing for COVID-19 patients throughout the pandemic and to determine factors associated with their prescription. MethodsThis cohort study used electronic health records of COVID-19 cases admitted to public hospitals in Hong Kong from 21 January 2020 to 30 September 2022. We assessed the prevalence and rates of inpatient antibacterial drug use, using days of therapy/1000 patient days (DOT/1000PD), and examined the association of baseline factors and disease severity with receipt of an inpatient antibacterial drug prescription. ResultsAmong 65,810 inpatients, 54.0% were prescribed antibacterial drugs at a rate of 550.5 DOT/1000PD. Antibacterial use was lowest during wave 4 (28.0%; 246.9 DOT/1000PD), peaked in early wave 5 (64.6%; 661.2 DOT/1000PD), and then modestly declined in late wave 5 (43.2%; 464.1 DOT/1000PD) starting on 23 May 2022. Older age, increased disease severity, and residing in an elderly care home were strongly associated with increased odds of prescription, while receiving [≥] 2 doses of COVID-19 vaccines and pre-admission use of coronavirus antivirals were associated with lower odds. ConclusionsThe rate of inpatient antibacterial prescribing initially declined during the pandemic, but increased during the Omicron wave when hospital capacity was overwhelmed. Despite the availability of COVID-19 vaccines and antiviral drugs, antibacterial drug use among COVID-19 inpatients remained high into late 2022. HIGHLIGHTSO_LIThe prevalence of antibacterial drug use in hospitalized COVID-19 cases in Hong Kong declined gradually during the first four COVID-19 epidemic waves to 28.0%, but increased to 64.6% with the spread of the Omicron variant in early 2022. C_LIO_LIThe majority of antibacterial drug prescriptions were for Access and Watch drugs, with limited use of combination therapy or macrolides. C_LIO_LIOlder age and more severe disease were strongly associated with an inpatient antibacterial drug prescription, while vaccination and initiation of COVID-19-specific antivirals reduced the odds of antibacterial prescription. C_LIO_LIDespite moderate-to-high levels of vaccine coverage and the availability of antiviral drugs, 43% of COVID-19 inpatients still received antibacterial drugs in late 2022. C_LI