Release date: 1 February 2023
The HKSAR Government attaches great importance to the threat of antimicrobial resistance (AMR). A High Level Steering Committee (HLSC) chaired by the Secretary for Food and Health has been established to formulate strategies and implement actions to combat AMR in Hong Kong. The first Hong Kong Strategy and Action Plan on Antimicrobial Resistance (2017-2022) was launched in July 2017, and the second action plan (2023-2027) in November 2022.
The Action Plans set out monitoring antimicrobial usage as one of the strategic actions. Activity 3.2.1 of both Action Plans suggested collecting the antimicrobial dispensing data from Hospital Authority (HA) to monitor antimicrobial usage in public hospitals and clinics. After studying the antimicrobial dispensing data of public hospitals and clinics of HA (including both non-inpatient and inpatient services), AMU surveillance reports were compiled and published on the Centre for Health Protection website. This is the fifth report which provides a brief account of the surveillance findings for year 2021. Please click here to view further details.
Following the recommendation of WHO for AMU surveillance[1], the following core set of antimicrobials under WHO’s Anatomical Therapeutic Chemical (ATC) classification system (Year 2021) was adopted for surveillance purpose. Only antimicrobials given for systemic use[2] were included, while topical antimicrobials were excluded.
| ATC Code | ATC Group/Subgroup |
| J01 | Antibacterials for systemic use |
| P01AB | Nitroimidazole derivatives, agents against amoebiasis and other protozoal diseases |
| A07AA | Antibiotics, intestinal antiinfectives |
Dispensing data for a total of 15 broad-spectrum antimicrobials identified by experts in HA (also known as ‘Big Guns’) were examined because of their importance in treating resistant infections.
The surveillance period for AMU is defined by calendar year. Results were analysed and presented as Defined Daily Dose (DDD)[3]. The 2021 version of WHO ATC DDD constants was adopted in this report. As there has been no change in DDD constants for those antimicrobials dispensed in HA captured by this surveillance system, the DDD constants adopted for calculation for previous years remained the same as in the last report of 2020.
Since the first Action Plan, i.e. Action Plan 2017-2022, was published in July 2017, the situation of 2016 has been chosen as the baseline for comparison.
Following the practice of the European Centre for Disease Prevention and Control (ECDC)[4], compound annual growth rate (CAGR) was adopted to illustrate the average annual rate of change when comparing antimicrobials dispensed in 2021 with that in 2016.
CAGR = (SU2021 / SU2016)(1/5) - 1
In this equation, SU2021 and SU2016 refer to the total amount of antimicrobials dispensed for year 2021 and 2016 respectively.
Total antimicrobials dispensed in public hospitals and clinics
For inpatient services of HA, the total antimicrobial dispensing volume in 2021 was about 868.38 DDD/1,000 patient days, which was lower than the pre-COVID era of 2016-2019 (ranged from 895.88 to 906.10 DDD/1,000 patient days). On the other hand, for non-inpatient services, the total antimicrobial dispensed in 2021 was 271.90 DDD/1,000 attendances, similar to that of the pre-COVID era (ranging from 256.16 to 274.41 DDD/1,000 attendances).
Meanwhile, the service volume of various HA services in 2021 has rebounded to a level similar to the pre-COVID era, in which the total service volume in 2021 for non-inpatient services and inpatient services was 16,339,000 attendances and 7,138,000 patient days, respectively. In comparison, non-inpatient and inpatient services volume during the pre-COVID era from 2016 to 2019 ranged from 16,095,000 to 16,533,000 attendances and 6,967,000 to 7,557,000 patient days respectively.
Ten Most Dispensed Antimicrobials in Public Hospitals and Clinics
The ten most dispensed antimicrobials (in DDD) accounted for around 80% of all antimicrobials dispensed for HA services in 2021. Amoxicillin/ clavulanate (Augmentin) continued to be the most dispensed antimicrobial in 2021, accounting for 42.26% of all antimicrobials dispensed in HA of the year. Compared with 2020, the majority of the ten most dispensed antimicrobials showed a rebound in dispensing volume. It was also noted that the dispensing volume of doxycycline and co-trimoxazole continued to increase since 2016 with CAGR (16-21) being 13.71% and 10.84%, respectively. Doxycycline has surpassed levofloxacin and has become the second most dispensed antimicrobial since 2018. Besides, cloxacillin showed the largest decrease in dispensing quantity among the ten most dispensed antimicrobials from 2016 to 2021 (CAGR (16-21): -13.74%).
Antimicrobials dispensed in HA by service
In 2021, the number of attendances rebounded in all non-inpatient services. Meanwhile, the overall dispensing quantity of antimicrobials in non-inpatient services of HA showed an increase in CAGR (16-21) of 5.18% (in DDD/1,000 attendances) when considering those attendances dispensed with antimicrobials only. In addition to the rebound in the number of attendance with antimicrobials, the dispensing quantity of ‘Specialist Out-patient (Clinical)’ continued to increase from 2016 (CAGR (16-21): 5.38%).
Among the ten most dispensed antimicrobials in non-inpatient services, amoxicillin/ clavulanate (Augmentin) continued to be the most dispensed antimicrobial in 2021 since 2016, accounting for around 40% of the total antimicrobials dispensed in HA non-inpatient services.
The dispensing volumes of doxycycline and rifaximin have continued to increase since 2016 (CAGR (16-21): 15.28% and 28.14%, respectively). Doxycycline continued to be the second most dispensed antimicrobial in non-inpatient services in 2021 after Augmentin. Further examination of the data of 2020 and 2021 revealed that the dispensing volume of doxycycline has dropped in ‘Accident & Emergency’ (7.89 to 7.60 DDD/1,000 attendances, CAGR (20-21): -3.71%) and ‘Primary Care (GOPC)’ (8.26 to 8.01 DDD/1,000 attendances, CAGR (20-21): -3.01%), but raised in ‘Specialist Out-patient (Clinical)’ (29.25 to 30.26 DDD/1,000 attendances, CAGR (20-21): 3.44%).
Compared with 2020, clarithromycin and amoxicillin showed rebounds in the dispensing volume (CAGR (20-21): 15.75% and 25.61%, respectively). In contrast, the dispensing volume of cloxacillin has continued to drop since 2016 (CAGR (16-21): -15.52%).
In 2021, the number of patient days rebounded by various degrees in different specialties of inpatient services of HA. Meanwhile, the antimicrobials dispensed (DDD per 1,000 patient days) showed a decrease from 2020 in all specialties by different degrees (CAGR (20-21) range -0.39% to -6.53%).
Regarding the ten most dispensed antimicrobials in inpatient services in 2021, Amoxicillin/ clavulanate (Augmentin) continued to be the most dispensed antimicrobial in inpatient services in 2021 (387.36 DDD/1,000 patient days), followed by doxycycline (65.56 DDD/1,000 patient days), piperacillin/ tazobactam (61.22 DDD/1,000 patient days), meropenem (29.98 DDD/1,000 patient days), levofloxacin (64.44 DDD/1,000 patient days), ceftriaxone (27.46 DDD/1,000 patient days), cefuroxime (20.45 DDD/1,000 patient days), vancomycin (18.77 DDD/1,000 patient days), co-trimoxazole (18.49 DDD/1,000 patient days), and cloxacillin (15.97 DDD/1,000 patient days). In addition, the dispensing volume of doxycycline in 2021 showed the first annual reduction since 2016 compared with 2020 (CAGR (20-21): -15.73%).
Broad-spectrum Antimicrobials Dispensed in Inpatient Services
Regarding the broad-spectrum antimicrobials, their dispensing quantities account (in DDD) for about 9.17% of total antimicrobials dispensed in HA in 2021.
The three most dispensed broad-spectrum antimicrobials in 2021 continued to be piperacillin/ tazobactam, meropenem and vancomycin (61.27, 29.92, and 18.71 DDD/1,000 patient days, respectively). However, in 2021, it was first observed since 2016 that the dispensing volume of these three antimicrobials plateaued, and piperacillin/ tazobactam showed a decrease for the first time since 2016 when compared with 2020 (CAGR (20-21): -0.91%).
Meanwhile, being the fourth most dispensed broad-spectrum antimicrobials, the increasing dispensing volume of ertapenem from 2016 (CAGR (16-21): 7.62%) would warrant monitoring.
In 2021, ‘ICU/ HDU’ continued to be the specialty of inpatient services of HA with the largest quantity of broad-spectrum antimicrobials dispensed (513.89 DDD per 1,000 patient days), followed by ‘Medicine’, ‘Surgery’, ‘O&T’ and ‘Others’ (160.90, 146.28, 95.09 and 76.57 DDD/ 1,000 patient days respectively). The quantity of broad-spectrum antimicrobial dispensed in ‘ICU/ HDU’ and ‘Surgery’ peaked in 2020 and showed a reduction in 2021 (CAGR (20-21): -6.56% and -6.97%). While the dispensing volumes in ‘Medicine’, ‘O&T’ and ‘Others’ specialties continued to increase from 2020 (CAGR (20-21): 2.30%, 5.23% and 1.02% respectively). In addition, piperacillin/ tazobactam, meropenem, and vancomycin showed a reduction in dispensed volume in ‘ICU/ HDU’ in 2021 (CAGR (20-21): -7.86%, -6.68% and -9.63% respectively).
The key findings in 2021 surveillance (2 years since the COVID-19 pandemic) included:
Continuous monitoring of the antimicrobial usage in HA hospitals/ clinics to assess the effectiveness of the Antibiotics Stewardship Programme (ASP).
Given the discrepant trends of doxycycline dispensed in inpatient and non-inpatient settings, further examinations would be warranted.
It is anticipated that HA service will continue to resume in 2022 and close monitoring of AMU for both inpatient and non-inpatient services is needed to assess for any impact of COVID-19 on AMU.
We would like to acknowledge stakeholders from HA including the Information Technology & Health Informatics Division, Quality and Safety Division, Strategy and Planning Division, Chief Pharmacist’s Office, and various Working Groups for provision of input to facilitate compilation of the AMU surveillance findings for year 2021.
Please click here to view the Past Reports.
[1] https://www.who.int/publications/i/item/9789240012639
[2] Only antimicrobials given by oral, parenteral, rectal and inhalation were included in the surveillance
[3] DDD is a standardised unit adopted by WHO to facilitate the comparison of drug usage.
[4] https://www.ecdc.europa.eu/sites/default/files/documents/Antimicrobial-consumption-in-the-EU-Annual-Epidemiological-Report-2019.pdf (same method was also adopted in year 2020 report)