Post-doctoral Fellow The University of Hong Kong Hong Kong, Hong Kong
Background: Antibacterial drugs were widely prescribed to hospitalized patients with COVID-19 early in the pandemic. Hong Kong experienced four epidemic waves (1-4) caused by the ancestral strain of SARS-CoV-2 in 2020-2021 and a large Omicron wave in 2022, yet antibacterial drug prescribing has not been assessed for COVID-19 inpatients throughout the pandemic .
Objectives: To describe inpatient antibacterial drug prescribing for inpatients with COVID-19 throughout the pandemic and to determine factors associated with their prescription.
Methods: We calculated the prevalence and rates (days of therapy (DOT)/1000 patient-days) of antibacterial drug use in patients admitted to all public hospitals with community-acquired COVID-19 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. Epidemic waves were defined as wave 1-2 (1 January 2020 to 30 June 2020), wave 3 (1 July 2020 to 31 October 2020), wave 4 (1 November 2020 to 30 December 2021), early wave 5 (31 December 2021 to 22 May 2022) and late wave 5 (23 May 2022 to 30 September 2022).
Results: We included 65,810 patients hospitalized with COVID-19. The overall prevalence of antibacterial use was 54.0%. It was lowest in wave 4 (28.0%), more than doubled in early wave 5 (64.6%), and then modestly declined in late wave 5 (43.2%). Older age, more severe disease and being admitted from a residential home for the elderly were each associated with a higher odds of an inpatient antibacterial drug prescription. In contrast, admission during wave 3, wave 4 or late wave 5, > 1 dose of COVID-19 vaccines and pre-admission use of coronavirus antiviral drugs were associated with lower odds. Rates of antibacterial drug use ranged from 246.9 DOT/1000 patient-days in waves 1-2 to 661.2 DOT/1000 patient-days in early wave 5, which also had the greatest rates of watch and not recommended antibacterial drug use. Three drugs 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 drugs.
Conclusions: The rate of inpatient antibacterial drug 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.
