View Article PDF

We thank Metcalfe et al (18 January 2019)1 for their careful consideration of our article describing ethnic disparities in community antibacterial dispensing in New Zealand during 2015,2 and for their comments on whether the health of Māori and Pacific people in New Zealand would be best served by increasing or reducing their current rates of antibacterial dispensing. We consider that the data in our article and in other recently published studies shows that: (a) the overall rate of antibacterial dispensing in New Zealand is very high compared with many other developed nations,2,3(b) a large proportion of antibacterial dispensing in New Zealand is likely to be inappropriate conferring little or no clinical benefit,2,4,5 and (c) the rates of dispensing of antibiotics for Māori and Pacific people differs relatively little from the rates of dispensing for other ethnic groups,2,4,5 despite a significantly higher incidence of many infectious diseases in Māori and Pacific people.6–8

We found the rate of community dispensing of antibiotics for people of European ethnicity in New Zealand during 2015 was 3.02 prescription items/1,000 population/day.2 This was approximately 3.3 times higher than the national rate in Sweden (0.90), 2.1 times higher than the national rate in Denmark (1.45), 1.7 times higher than the national rate in Canada (1.79), 1.5 times higher than the national rate in England (1.95), and 1.3 times higher than the estimated national rate in the US (2.31).2,9 While the incidence of infectious diseases in European people in New Zealand no doubt differs from that in residents of these other nations, we would be surprised if differences in the incidence of infectious disease justified these major differences in the rates of community antibacterial dispensing. A much more likely explanation is that the high rate of antibacterial dispensing for European people in New Zealand reflects higher rates of inappropriate prescribing in New Zealand than in these other nations.

Metcalfe et al suggest that we may have overestimated the magnitude of inappropriate antibiotic prescribing in New Zealand and refer to articles indicating that the rate of overprescribing might be approximately 30% in the US,10 and 8–23% in the UK.11 We note two recently published studies that have used large general practice databases to estimate current rates of inappropriate community antimicrobial prescribing for patients with respiratory tract infections in the UK12 and Australia.13 These studies estimated that inappropriate prescribing accounted for: 75% of prescribing for acute cough in the UK, 87% of prescribing for acute rhinosinusitis in the UK and 77% in Australia, and 80% of prescribing for acute otitis media in the UK and 45% in Australia. As these conditions comprise a large proportion of community antimicrobial prescribing, we believe it reasonable to estimate that approximately 50% of total community antibiotic dispensing in New Zealand may be inappropriate.

There is strong evidence that the overall rate of inappropriate antibiotic dispensing is very high in New Zealand. For example, Figure 1 shows that, overall, an antibiotic was dispensed at 61% (31,082/50,691) of consultations for acute upper respiratory tract infections in 111 New Zealand general practices during 2014.

Figure 1: The proportion of consultations for an acute upper respiratory tract infection, at 111 general practices in New Zealand, during 2014, that were associated with dispensing of an antibiotic during the subsequent seven days. Each column represents one general practice.

c

In approximately 73% of general practices included in this survey an antibiotic was prescribed and dispensed for more than 50% of patients who presented with a respiratory tract infection. (Personal communication Tomlin A, Tilyard M. 2019) Many guidelines suggest that antibiotics should be prescribed for a minority of such patients.12–14

Other data indicating high rates of inappropriate antibiotic prescribing include a 26% increase in the national rate of antibacterial dispensing during winter in New Zealand,2 presumably mostly for patients with self-limited viral respiratory tract infections, and an average annual rate of 1.9 antibiotic dispensings/child/year in the first five years of life, for the 5,581 children enrolled in the Growing Up in New Zealand study.5 We acknowledge that there are no studies that have directly measured the rate of inappropriate community antimicrobial prescribing in New Zealand, however we consider that the figure of 8–23% suggested by Metcalfe et al is likely to be a significant underestimate. The available data suggest to us that the overall rate of inappropriate community antibiotic prescribing in New Zealand is more likely to be between 30% and 50%. Furthermore, the marked similarity between ethnic groups in the magnitude of the increase in antibiotic dispensing during the winter,2 suggests that inappropriate antibiotic dispensing is a comparable problem for all ethnic groups in New Zealand.

The higher incidence of many infectious diseases in Māori and Pacific people than in people of other ethnicities in New Zealand,2,6-8 is a compelling reason why Māori and Pacific people require higher rates of antibiotic dispensing. We appreciate the efforts of Metcalfe et al to calculate a suitable ratio for the rate of antibiotic dispensing for Māori and Pacific people in relation to that for non-Māori and non-Pacific people. We do not disagree with their suggestion that an appropriate rate of antibiotic dispensing for Māori and Pacific people may be approximately 1.66 times the rate for non-Māori and non-Pacific people.1 However, we strongly believe that the appropriate rate of antibiotic dispensing for Māori and Pacific people should be estimated in relation to the appropriate rate of dispensing for people of other ethnicities, and not in relation to the current excessively high rates.

Here we consider two scenarios in which we assume: (a) that in non-Māori and non-Pacific people, either 30% or 50% of antibiotic dispensings are inappropriate; and (b) that the appropriate rate of antibiotic dispensing for Māori and Pacific people is 1.66 times the appropriate rate of dispensing for non-Māori and non-Pacific people.

If approximately 30% of current dispensing for non-Māori and non-Pacific people is inappropriate, then the estimated rate of appropriate dispensing for these people is approximately 2.1 (70% X 3.02) antibiotic dispensings/1,000 population/day, a rate midway between the current national dispensing rates in the US and Canada, and slightly higher than the current national dispensing rate in England. The rate of appropriate antibiotic dispensing for Māori and Pacific people may therefore be estimated as approximately 3.5 (1.66 X 2.1) antibiotic dispensings/1,000 population/day, which is similar to the actual current rates of 3.2 (Māori) and 3.5 (Pacific people) antibiotic dispensings/1,000 population/day.

If approximately 50% of current dispensing for non-Māori and non-Pacific people is inappropriate, then the estimated rate of appropriate dispensing for these people is approximately 1.5 (50% X 3.02) antibiotic dispensings/1,000 population/day, a rate similar to the current national dispensing rate in Denmark. The rate of appropriate antibiotic dispensing for Māori and Pacific people may therefore be estimated as approximately 2.5 (1.66 X 1.5) antibiotic dispensings/1,000 population/day, significantly lower than the current rates of 3.2 (Māori) and 3.5 (Pacific people) antibiotic dispensings/1,000 population/day.

We believe that Māori and Pacific people currently do “suffer from double jeopardy, being harmed by both over-prescribing and under-prescribing” as Metcalfe et al suggest.1 Both under- and over-prescribing contribute to health inequities in these ethnic groups. The higher proportion of staphylococcal disease in Māori and Pacific people caused by methicillin-resistant Staphylococcus aureus (MRSA)15 is likely to be in part a consequence of over-prescribing of antibiotics for Māori and Pacific people, while their higher rates of admission to hospital for infectious diseases6–8 are strongly suggestive of harm arising from under-prescribing of antibiotics. Therein lies the challenge with antimicrobial stewardship programmes in New Zealand. As we suggested in our previous article,2 we must reduce our rates of inappropriate antibiotic prescribing, while increasing our rates of appropriate antibiotic prescribing. The need to reduce inappropriate antibiotic prescribing is not just limited to non-Māori and non-Pacific people since unnecessary antibiotics should not be prescribed for any patient. The need to increase appropriate antibiotic prescribing is greatest in Māori and Pacific people. Therefore, we reiterate our previous recommendation that antimicrobial stewardship programmes should be sufficiently nuanced to not only reduce rates of inappropriate prescribing but also to increase rates of treatment for infections that do require antimicrobial therapy. We welcome further commentary on how this delicate but important balance can be achieved in an equitable manner across all population groups in New Zealand.

Summary

Abstract

Aim

Method

Results

Conclusion

Author Information

Mark Thomas, Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland; Naomi Whyler, Infectious Diseases, Auckland City Hospital, Auckland; Andrew Tomlin, Best Practice Advocacy Centre, Dunedin; Murray Tilyard Best Practice Advocacy Centre, Dunedin.

Acknowledgements

Correspondence

Associate Professor Mark Thomas, Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, 85 Park Rd, Grafton, University of Auckland, Auckland.

Correspondence Email

mg.thomas@auckland.ac.nz

Competing Interests

Nil.

  1. WHO. Worldwide country situation analysis: response to antimicrobial resistance. 2015. ISBN9789241564946. Available at: http://www.who.int/antimicrobial-resistance/publications/situationanalysis/en/
  2. The Review on Antimicrobial Resistance. Antimicrobial Resistance: Tackling a crisis for the health and wealth of nations. 2014. Available at: https://amr-review.org/
  3. Austin DJ, Anderson RM. Studies of antibiotic resistance within the patient, hospitals and the community using simple mathematical models. Phil Trans R Soc Lond B. 1999; 354(1384):721–38.
  4. Thomas MG, Smith A, Tilyard M. Rising antimicrobial resistance: a strong reason to reduce excessive antimicrobial consumption in New Zealand. N Z Med J 2014; 127(1394):72–84.
  5. Williamson DA, Roos RF, Verrall A. Antibiotic consumption in New Zealand, 2006–2014. The Institute of Environmental Sciences and Research Ltd. Porirua, New Zealand. 2016. Available at: https://surv.esr.cri.nz/PDF_surveillance/AntibioticConsumption/2014/Antibiotic_Consumption_Report_Final.pdf
  6. Duffy E, Ritchie S, Metcalfe S, et al. Antibacterials dispensed in the community comprise 85–95% of total human antibacterial consumption. J Clin Pharm Ther 2018; 43:59–64.
  7. Grijalva CG, Nuorti JP, Griffin MR. Antibiotic prescription rates for acute respiratory tract infections in US ambulatory settings. JAMA 2009; 302:758–66.
  8. Fleming-Dutra KE, Hersh AL, Shapiro DJ, et al. Prevalence of inappropriate antibiotic prescriptions among US ambulatory care visits, 2010–2011. JAMA 2016; 315:1864–73.
  9. Baker MG, Telfar Barnard L, Kvalsvig A, et al. Increasing incidence of serious infectious diseases and inequalities in New Zealand: a national epidemiological study. Lancet 2012; 379:1112–9.
  10. Jack S, Williamson D, Galloway Y, et al. Interim evaluation of the sore throat component of the rheumatic fever prevention programme – quantitative findings. The Institute of Environmental Science and Research Ltd. Porirua, New Zealand; 2015. Available at: http://www.health.govt.nz/publication/interim-evaluation-sore-throat-management-component-new-zealand-rheumatic-fever-prevention-programme
  11. Norris P, Horsburgh S, Keown S, et al. Too much and too little? Prevalence and extent of antibiotic use in a New Zealand region. J Antimicrob Chemother 2011; 66:1921–6.
  12. Ministry of Health. Ethnicity data protocols for the health and disability sector. 2004. Available at: http://www.health.govt.nz/publication/ethnicity-data-protocols-health-and-disability-sector
  13. Salmond C, Crampton P. Development of New Zealand’s deprivation index (NZDep) and its uptake as a national policy tool. Can J Pub Health 2012; 103 (Suppl. 2):S7–S11.
  14. Collaborating Centre for Drug Statistics Methodology. Guidelines for ATC classification and DDD assignment 2013. Oslo, 2012. Available at: http://www.whocc.no/atc_ddd_index/
  15. Statistics NZ. National population estimates: at 30 June 2015.
  16. Available at: http://www.stats.govt.nz/browse_for_stats/population/estimates_and_projections/NationalPopulationEstimates_HOTPAt30Jun15.aspx
  17. Australian Commission on Safety and Quality in Healthcare. AURA 2016 - First Australian report on antimicrobial use and resistance in human health. Available at: https://www.safetyandquality.gov.au/publications/aura-2016-first-australian-report-on-antimicrobial-use-and-resistance-in-human-health/
  18. Hicks LA, Bartoces MG, Roberts RM, et al. US outpatient antibiotic prescribing variation according to geography, patient population, and provider specialty in 2011. Clin Infect Dis 2015; 60:1308–16.
  19. Swedres-Svarm 2014. Consumption of antibiotics and occurrence of antibiotic resistance in Sweden. Solna/Uppsala ISSN 1650-6332. Available at: http://www.sva.se/en/antibiotics/svarm-reports
  20. Danmap 2015 – Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, food and humans in Denmark. ISSN 1600-2013. Available at: http://www.danmap.org.
  21. Canadian Integrated Program for Antimicrobial Resistance Surveillance. Human antimicrobial use report, 2011. Available at: http://publications.gc.ca/collections/collection_2014/aspc-phac/HP40-109-2014-eng.pdf
  22. Metcalfe S, Laking G, Arnold J. Variation in the use of medicines by ethnicity during 2006/07 in New Zealand: a preliminary analysis. N Z Med J 2013; 126:14–41.
  23. Hobbs MR, Grant CC, Ritchie SR, et al. Antibiotic consumption by New Zealand children: exposure is near universal by the age of 5 years. J Antimicrob Chemother 2017;72:1832-40.
  24. Walls G, Vandal AC, du Plessis T, et al. Socioeconomic factors correlating with community antimicrobial prescribing. N Z Med J 2015; 128(1417):16–23.
  25. Williamson DA, Lim A, Thomas MG, et al. Incidence, trends and demographics of Staphylococcus aureus infections in Auckland, New Zealand, 2001–2011. BMC Infectious Diseases 2013; 13:569.
  26. Williamson DA, Monecke S, Heffernan H, et al. High usage of topical fusidic acid and rapid clonal expansion of fusidic acid-resistant Staphylococcus aureus: a cautionary tale. Clin Infect Dis 2014; 59:1451–4.
  27. Saari A, Virta LJ, Sankilampi U, et al. Antibiotic exposure in infancy and risk of being overweight in the first 24 months of life. Pediatrics 2015; 135:617–26.
  28. Dao MC, Everard A, Aron-Wisnewsky J, et al. Akkermansia muciniphila and improved metabolic health during a dietary intervention in obesity: relationship with gut microbiome richness and ecology. Gut 2016; 65:426–36.
  29. Ministry of Health. Annual update of key results 2015/16: New Zealand Health Survey. Wellington: Ministry of Health. Available at: http://www.health.govt.nz/system/files/documents/publications/annual-update-key-results-2015-16-nzhs-dec16-v2.pdf
  30. Williamson DA, Zhang J, Ritchie SR, et al. Staphylococcus aureus infections in New Zealand, 2000–2011. Emerg Infect Dis 2014; 20:1157–62.
  31. Institute of Environmental Science and Research Ltd. Invasive pneumococcal disease in New Zealand, 2015. Porirua: ESR; 2017. Available at: https://surv.esr.cri.nz/PDF_surveillance/IPD/2015/2015IPDAnnualReport.pdf
  32. Heart Foundation of New Zealand. Group A streptococcal sore throat management guideline. 2014 update. Auckland, Heart Foundation of New Zealand. Available at: http://assets.heartfoundation.org.nz/shop/heart-healthcare/non-stock-resources/gas-sore-throat-rheumatic-fever-guideline.pdf
  33. Best Practice Advocacy Centre. 2015. Respiratory tract infections (self-limiting) – reducing antibiotic prescribing. BPAC. Available at: http://www.bpac.org.nz/guidelines/1/docs/Respiratory-tract-infections-%28self-limiting%29-reducing-antibiotic-prescribing.pdf
  34. European Centre for Disease Prevention and Control. Quality indicators for antibiotic consumption in the community. Available at: https://ecdc.europa.eu/en/antimicrobial-consumption/database/quality-indicators
  35. Suda KJ, Hicks LA, Roberts RM, et al. Trends and seasonal variation in outpatient antibiotic prescription rates in the United States, 2006 to 2010. Antimicrob Ag Chemother 2014; 58:2763–6.

Contact diana@nzma.org.nz
for the PDF of this article

View Article PDF

We thank Metcalfe et al (18 January 2019)1 for their careful consideration of our article describing ethnic disparities in community antibacterial dispensing in New Zealand during 2015,2 and for their comments on whether the health of Māori and Pacific people in New Zealand would be best served by increasing or reducing their current rates of antibacterial dispensing. We consider that the data in our article and in other recently published studies shows that: (a) the overall rate of antibacterial dispensing in New Zealand is very high compared with many other developed nations,2,3(b) a large proportion of antibacterial dispensing in New Zealand is likely to be inappropriate conferring little or no clinical benefit,2,4,5 and (c) the rates of dispensing of antibiotics for Māori and Pacific people differs relatively little from the rates of dispensing for other ethnic groups,2,4,5 despite a significantly higher incidence of many infectious diseases in Māori and Pacific people.6–8

We found the rate of community dispensing of antibiotics for people of European ethnicity in New Zealand during 2015 was 3.02 prescription items/1,000 population/day.2 This was approximately 3.3 times higher than the national rate in Sweden (0.90), 2.1 times higher than the national rate in Denmark (1.45), 1.7 times higher than the national rate in Canada (1.79), 1.5 times higher than the national rate in England (1.95), and 1.3 times higher than the estimated national rate in the US (2.31).2,9 While the incidence of infectious diseases in European people in New Zealand no doubt differs from that in residents of these other nations, we would be surprised if differences in the incidence of infectious disease justified these major differences in the rates of community antibacterial dispensing. A much more likely explanation is that the high rate of antibacterial dispensing for European people in New Zealand reflects higher rates of inappropriate prescribing in New Zealand than in these other nations.

Metcalfe et al suggest that we may have overestimated the magnitude of inappropriate antibiotic prescribing in New Zealand and refer to articles indicating that the rate of overprescribing might be approximately 30% in the US,10 and 8–23% in the UK.11 We note two recently published studies that have used large general practice databases to estimate current rates of inappropriate community antimicrobial prescribing for patients with respiratory tract infections in the UK12 and Australia.13 These studies estimated that inappropriate prescribing accounted for: 75% of prescribing for acute cough in the UK, 87% of prescribing for acute rhinosinusitis in the UK and 77% in Australia, and 80% of prescribing for acute otitis media in the UK and 45% in Australia. As these conditions comprise a large proportion of community antimicrobial prescribing, we believe it reasonable to estimate that approximately 50% of total community antibiotic dispensing in New Zealand may be inappropriate.

There is strong evidence that the overall rate of inappropriate antibiotic dispensing is very high in New Zealand. For example, Figure 1 shows that, overall, an antibiotic was dispensed at 61% (31,082/50,691) of consultations for acute upper respiratory tract infections in 111 New Zealand general practices during 2014.

Figure 1: The proportion of consultations for an acute upper respiratory tract infection, at 111 general practices in New Zealand, during 2014, that were associated with dispensing of an antibiotic during the subsequent seven days. Each column represents one general practice.

c

In approximately 73% of general practices included in this survey an antibiotic was prescribed and dispensed for more than 50% of patients who presented with a respiratory tract infection. (Personal communication Tomlin A, Tilyard M. 2019) Many guidelines suggest that antibiotics should be prescribed for a minority of such patients.12–14

Other data indicating high rates of inappropriate antibiotic prescribing include a 26% increase in the national rate of antibacterial dispensing during winter in New Zealand,2 presumably mostly for patients with self-limited viral respiratory tract infections, and an average annual rate of 1.9 antibiotic dispensings/child/year in the first five years of life, for the 5,581 children enrolled in the Growing Up in New Zealand study.5 We acknowledge that there are no studies that have directly measured the rate of inappropriate community antimicrobial prescribing in New Zealand, however we consider that the figure of 8–23% suggested by Metcalfe et al is likely to be a significant underestimate. The available data suggest to us that the overall rate of inappropriate community antibiotic prescribing in New Zealand is more likely to be between 30% and 50%. Furthermore, the marked similarity between ethnic groups in the magnitude of the increase in antibiotic dispensing during the winter,2 suggests that inappropriate antibiotic dispensing is a comparable problem for all ethnic groups in New Zealand.

The higher incidence of many infectious diseases in Māori and Pacific people than in people of other ethnicities in New Zealand,2,6-8 is a compelling reason why Māori and Pacific people require higher rates of antibiotic dispensing. We appreciate the efforts of Metcalfe et al to calculate a suitable ratio for the rate of antibiotic dispensing for Māori and Pacific people in relation to that for non-Māori and non-Pacific people. We do not disagree with their suggestion that an appropriate rate of antibiotic dispensing for Māori and Pacific people may be approximately 1.66 times the rate for non-Māori and non-Pacific people.1 However, we strongly believe that the appropriate rate of antibiotic dispensing for Māori and Pacific people should be estimated in relation to the appropriate rate of dispensing for people of other ethnicities, and not in relation to the current excessively high rates.

Here we consider two scenarios in which we assume: (a) that in non-Māori and non-Pacific people, either 30% or 50% of antibiotic dispensings are inappropriate; and (b) that the appropriate rate of antibiotic dispensing for Māori and Pacific people is 1.66 times the appropriate rate of dispensing for non-Māori and non-Pacific people.

If approximately 30% of current dispensing for non-Māori and non-Pacific people is inappropriate, then the estimated rate of appropriate dispensing for these people is approximately 2.1 (70% X 3.02) antibiotic dispensings/1,000 population/day, a rate midway between the current national dispensing rates in the US and Canada, and slightly higher than the current national dispensing rate in England. The rate of appropriate antibiotic dispensing for Māori and Pacific people may therefore be estimated as approximately 3.5 (1.66 X 2.1) antibiotic dispensings/1,000 population/day, which is similar to the actual current rates of 3.2 (Māori) and 3.5 (Pacific people) antibiotic dispensings/1,000 population/day.

If approximately 50% of current dispensing for non-Māori and non-Pacific people is inappropriate, then the estimated rate of appropriate dispensing for these people is approximately 1.5 (50% X 3.02) antibiotic dispensings/1,000 population/day, a rate similar to the current national dispensing rate in Denmark. The rate of appropriate antibiotic dispensing for Māori and Pacific people may therefore be estimated as approximately 2.5 (1.66 X 1.5) antibiotic dispensings/1,000 population/day, significantly lower than the current rates of 3.2 (Māori) and 3.5 (Pacific people) antibiotic dispensings/1,000 population/day.

We believe that Māori and Pacific people currently do “suffer from double jeopardy, being harmed by both over-prescribing and under-prescribing” as Metcalfe et al suggest.1 Both under- and over-prescribing contribute to health inequities in these ethnic groups. The higher proportion of staphylococcal disease in Māori and Pacific people caused by methicillin-resistant Staphylococcus aureus (MRSA)15 is likely to be in part a consequence of over-prescribing of antibiotics for Māori and Pacific people, while their higher rates of admission to hospital for infectious diseases6–8 are strongly suggestive of harm arising from under-prescribing of antibiotics. Therein lies the challenge with antimicrobial stewardship programmes in New Zealand. As we suggested in our previous article,2 we must reduce our rates of inappropriate antibiotic prescribing, while increasing our rates of appropriate antibiotic prescribing. The need to reduce inappropriate antibiotic prescribing is not just limited to non-Māori and non-Pacific people since unnecessary antibiotics should not be prescribed for any patient. The need to increase appropriate antibiotic prescribing is greatest in Māori and Pacific people. Therefore, we reiterate our previous recommendation that antimicrobial stewardship programmes should be sufficiently nuanced to not only reduce rates of inappropriate prescribing but also to increase rates of treatment for infections that do require antimicrobial therapy. We welcome further commentary on how this delicate but important balance can be achieved in an equitable manner across all population groups in New Zealand.

Summary

Abstract

Aim

Method

Results

Conclusion

Author Information

Mark Thomas, Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland; Naomi Whyler, Infectious Diseases, Auckland City Hospital, Auckland; Andrew Tomlin, Best Practice Advocacy Centre, Dunedin; Murray Tilyard Best Practice Advocacy Centre, Dunedin.

Acknowledgements

Correspondence

Associate Professor Mark Thomas, Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, 85 Park Rd, Grafton, University of Auckland, Auckland.

Correspondence Email

mg.thomas@auckland.ac.nz

Competing Interests

Nil.

  1. WHO. Worldwide country situation analysis: response to antimicrobial resistance. 2015. ISBN9789241564946. Available at: http://www.who.int/antimicrobial-resistance/publications/situationanalysis/en/
  2. The Review on Antimicrobial Resistance. Antimicrobial Resistance: Tackling a crisis for the health and wealth of nations. 2014. Available at: https://amr-review.org/
  3. Austin DJ, Anderson RM. Studies of antibiotic resistance within the patient, hospitals and the community using simple mathematical models. Phil Trans R Soc Lond B. 1999; 354(1384):721–38.
  4. Thomas MG, Smith A, Tilyard M. Rising antimicrobial resistance: a strong reason to reduce excessive antimicrobial consumption in New Zealand. N Z Med J 2014; 127(1394):72–84.
  5. Williamson DA, Roos RF, Verrall A. Antibiotic consumption in New Zealand, 2006–2014. The Institute of Environmental Sciences and Research Ltd. Porirua, New Zealand. 2016. Available at: https://surv.esr.cri.nz/PDF_surveillance/AntibioticConsumption/2014/Antibiotic_Consumption_Report_Final.pdf
  6. Duffy E, Ritchie S, Metcalfe S, et al. Antibacterials dispensed in the community comprise 85–95% of total human antibacterial consumption. J Clin Pharm Ther 2018; 43:59–64.
  7. Grijalva CG, Nuorti JP, Griffin MR. Antibiotic prescription rates for acute respiratory tract infections in US ambulatory settings. JAMA 2009; 302:758–66.
  8. Fleming-Dutra KE, Hersh AL, Shapiro DJ, et al. Prevalence of inappropriate antibiotic prescriptions among US ambulatory care visits, 2010–2011. JAMA 2016; 315:1864–73.
  9. Baker MG, Telfar Barnard L, Kvalsvig A, et al. Increasing incidence of serious infectious diseases and inequalities in New Zealand: a national epidemiological study. Lancet 2012; 379:1112–9.
  10. Jack S, Williamson D, Galloway Y, et al. Interim evaluation of the sore throat component of the rheumatic fever prevention programme – quantitative findings. The Institute of Environmental Science and Research Ltd. Porirua, New Zealand; 2015. Available at: http://www.health.govt.nz/publication/interim-evaluation-sore-throat-management-component-new-zealand-rheumatic-fever-prevention-programme
  11. Norris P, Horsburgh S, Keown S, et al. Too much and too little? Prevalence and extent of antibiotic use in a New Zealand region. J Antimicrob Chemother 2011; 66:1921–6.
  12. Ministry of Health. Ethnicity data protocols for the health and disability sector. 2004. Available at: http://www.health.govt.nz/publication/ethnicity-data-protocols-health-and-disability-sector
  13. Salmond C, Crampton P. Development of New Zealand’s deprivation index (NZDep) and its uptake as a national policy tool. Can J Pub Health 2012; 103 (Suppl. 2):S7–S11.
  14. Collaborating Centre for Drug Statistics Methodology. Guidelines for ATC classification and DDD assignment 2013. Oslo, 2012. Available at: http://www.whocc.no/atc_ddd_index/
  15. Statistics NZ. National population estimates: at 30 June 2015.
  16. Available at: http://www.stats.govt.nz/browse_for_stats/population/estimates_and_projections/NationalPopulationEstimates_HOTPAt30Jun15.aspx
  17. Australian Commission on Safety and Quality in Healthcare. AURA 2016 - First Australian report on antimicrobial use and resistance in human health. Available at: https://www.safetyandquality.gov.au/publications/aura-2016-first-australian-report-on-antimicrobial-use-and-resistance-in-human-health/
  18. Hicks LA, Bartoces MG, Roberts RM, et al. US outpatient antibiotic prescribing variation according to geography, patient population, and provider specialty in 2011. Clin Infect Dis 2015; 60:1308–16.
  19. Swedres-Svarm 2014. Consumption of antibiotics and occurrence of antibiotic resistance in Sweden. Solna/Uppsala ISSN 1650-6332. Available at: http://www.sva.se/en/antibiotics/svarm-reports
  20. Danmap 2015 – Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, food and humans in Denmark. ISSN 1600-2013. Available at: http://www.danmap.org.
  21. Canadian Integrated Program for Antimicrobial Resistance Surveillance. Human antimicrobial use report, 2011. Available at: http://publications.gc.ca/collections/collection_2014/aspc-phac/HP40-109-2014-eng.pdf
  22. Metcalfe S, Laking G, Arnold J. Variation in the use of medicines by ethnicity during 2006/07 in New Zealand: a preliminary analysis. N Z Med J 2013; 126:14–41.
  23. Hobbs MR, Grant CC, Ritchie SR, et al. Antibiotic consumption by New Zealand children: exposure is near universal by the age of 5 years. J Antimicrob Chemother 2017;72:1832-40.
  24. Walls G, Vandal AC, du Plessis T, et al. Socioeconomic factors correlating with community antimicrobial prescribing. N Z Med J 2015; 128(1417):16–23.
  25. Williamson DA, Lim A, Thomas MG, et al. Incidence, trends and demographics of Staphylococcus aureus infections in Auckland, New Zealand, 2001–2011. BMC Infectious Diseases 2013; 13:569.
  26. Williamson DA, Monecke S, Heffernan H, et al. High usage of topical fusidic acid and rapid clonal expansion of fusidic acid-resistant Staphylococcus aureus: a cautionary tale. Clin Infect Dis 2014; 59:1451–4.
  27. Saari A, Virta LJ, Sankilampi U, et al. Antibiotic exposure in infancy and risk of being overweight in the first 24 months of life. Pediatrics 2015; 135:617–26.
  28. Dao MC, Everard A, Aron-Wisnewsky J, et al. Akkermansia muciniphila and improved metabolic health during a dietary intervention in obesity: relationship with gut microbiome richness and ecology. Gut 2016; 65:426–36.
  29. Ministry of Health. Annual update of key results 2015/16: New Zealand Health Survey. Wellington: Ministry of Health. Available at: http://www.health.govt.nz/system/files/documents/publications/annual-update-key-results-2015-16-nzhs-dec16-v2.pdf
  30. Williamson DA, Zhang J, Ritchie SR, et al. Staphylococcus aureus infections in New Zealand, 2000–2011. Emerg Infect Dis 2014; 20:1157–62.
  31. Institute of Environmental Science and Research Ltd. Invasive pneumococcal disease in New Zealand, 2015. Porirua: ESR; 2017. Available at: https://surv.esr.cri.nz/PDF_surveillance/IPD/2015/2015IPDAnnualReport.pdf
  32. Heart Foundation of New Zealand. Group A streptococcal sore throat management guideline. 2014 update. Auckland, Heart Foundation of New Zealand. Available at: http://assets.heartfoundation.org.nz/shop/heart-healthcare/non-stock-resources/gas-sore-throat-rheumatic-fever-guideline.pdf
  33. Best Practice Advocacy Centre. 2015. Respiratory tract infections (self-limiting) – reducing antibiotic prescribing. BPAC. Available at: http://www.bpac.org.nz/guidelines/1/docs/Respiratory-tract-infections-%28self-limiting%29-reducing-antibiotic-prescribing.pdf
  34. European Centre for Disease Prevention and Control. Quality indicators for antibiotic consumption in the community. Available at: https://ecdc.europa.eu/en/antimicrobial-consumption/database/quality-indicators
  35. Suda KJ, Hicks LA, Roberts RM, et al. Trends and seasonal variation in outpatient antibiotic prescription rates in the United States, 2006 to 2010. Antimicrob Ag Chemother 2014; 58:2763–6.

Contact diana@nzma.org.nz
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We thank Metcalfe et al (18 January 2019)1 for their careful consideration of our article describing ethnic disparities in community antibacterial dispensing in New Zealand during 2015,2 and for their comments on whether the health of Māori and Pacific people in New Zealand would be best served by increasing or reducing their current rates of antibacterial dispensing. We consider that the data in our article and in other recently published studies shows that: (a) the overall rate of antibacterial dispensing in New Zealand is very high compared with many other developed nations,2,3(b) a large proportion of antibacterial dispensing in New Zealand is likely to be inappropriate conferring little or no clinical benefit,2,4,5 and (c) the rates of dispensing of antibiotics for Māori and Pacific people differs relatively little from the rates of dispensing for other ethnic groups,2,4,5 despite a significantly higher incidence of many infectious diseases in Māori and Pacific people.6–8

We found the rate of community dispensing of antibiotics for people of European ethnicity in New Zealand during 2015 was 3.02 prescription items/1,000 population/day.2 This was approximately 3.3 times higher than the national rate in Sweden (0.90), 2.1 times higher than the national rate in Denmark (1.45), 1.7 times higher than the national rate in Canada (1.79), 1.5 times higher than the national rate in England (1.95), and 1.3 times higher than the estimated national rate in the US (2.31).2,9 While the incidence of infectious diseases in European people in New Zealand no doubt differs from that in residents of these other nations, we would be surprised if differences in the incidence of infectious disease justified these major differences in the rates of community antibacterial dispensing. A much more likely explanation is that the high rate of antibacterial dispensing for European people in New Zealand reflects higher rates of inappropriate prescribing in New Zealand than in these other nations.

Metcalfe et al suggest that we may have overestimated the magnitude of inappropriate antibiotic prescribing in New Zealand and refer to articles indicating that the rate of overprescribing might be approximately 30% in the US,10 and 8–23% in the UK.11 We note two recently published studies that have used large general practice databases to estimate current rates of inappropriate community antimicrobial prescribing for patients with respiratory tract infections in the UK12 and Australia.13 These studies estimated that inappropriate prescribing accounted for: 75% of prescribing for acute cough in the UK, 87% of prescribing for acute rhinosinusitis in the UK and 77% in Australia, and 80% of prescribing for acute otitis media in the UK and 45% in Australia. As these conditions comprise a large proportion of community antimicrobial prescribing, we believe it reasonable to estimate that approximately 50% of total community antibiotic dispensing in New Zealand may be inappropriate.

There is strong evidence that the overall rate of inappropriate antibiotic dispensing is very high in New Zealand. For example, Figure 1 shows that, overall, an antibiotic was dispensed at 61% (31,082/50,691) of consultations for acute upper respiratory tract infections in 111 New Zealand general practices during 2014.

Figure 1: The proportion of consultations for an acute upper respiratory tract infection, at 111 general practices in New Zealand, during 2014, that were associated with dispensing of an antibiotic during the subsequent seven days. Each column represents one general practice.

c

In approximately 73% of general practices included in this survey an antibiotic was prescribed and dispensed for more than 50% of patients who presented with a respiratory tract infection. (Personal communication Tomlin A, Tilyard M. 2019) Many guidelines suggest that antibiotics should be prescribed for a minority of such patients.12–14

Other data indicating high rates of inappropriate antibiotic prescribing include a 26% increase in the national rate of antibacterial dispensing during winter in New Zealand,2 presumably mostly for patients with self-limited viral respiratory tract infections, and an average annual rate of 1.9 antibiotic dispensings/child/year in the first five years of life, for the 5,581 children enrolled in the Growing Up in New Zealand study.5 We acknowledge that there are no studies that have directly measured the rate of inappropriate community antimicrobial prescribing in New Zealand, however we consider that the figure of 8–23% suggested by Metcalfe et al is likely to be a significant underestimate. The available data suggest to us that the overall rate of inappropriate community antibiotic prescribing in New Zealand is more likely to be between 30% and 50%. Furthermore, the marked similarity between ethnic groups in the magnitude of the increase in antibiotic dispensing during the winter,2 suggests that inappropriate antibiotic dispensing is a comparable problem for all ethnic groups in New Zealand.

The higher incidence of many infectious diseases in Māori and Pacific people than in people of other ethnicities in New Zealand,2,6-8 is a compelling reason why Māori and Pacific people require higher rates of antibiotic dispensing. We appreciate the efforts of Metcalfe et al to calculate a suitable ratio for the rate of antibiotic dispensing for Māori and Pacific people in relation to that for non-Māori and non-Pacific people. We do not disagree with their suggestion that an appropriate rate of antibiotic dispensing for Māori and Pacific people may be approximately 1.66 times the rate for non-Māori and non-Pacific people.1 However, we strongly believe that the appropriate rate of antibiotic dispensing for Māori and Pacific people should be estimated in relation to the appropriate rate of dispensing for people of other ethnicities, and not in relation to the current excessively high rates.

Here we consider two scenarios in which we assume: (a) that in non-Māori and non-Pacific people, either 30% or 50% of antibiotic dispensings are inappropriate; and (b) that the appropriate rate of antibiotic dispensing for Māori and Pacific people is 1.66 times the appropriate rate of dispensing for non-Māori and non-Pacific people.

If approximately 30% of current dispensing for non-Māori and non-Pacific people is inappropriate, then the estimated rate of appropriate dispensing for these people is approximately 2.1 (70% X 3.02) antibiotic dispensings/1,000 population/day, a rate midway between the current national dispensing rates in the US and Canada, and slightly higher than the current national dispensing rate in England. The rate of appropriate antibiotic dispensing for Māori and Pacific people may therefore be estimated as approximately 3.5 (1.66 X 2.1) antibiotic dispensings/1,000 population/day, which is similar to the actual current rates of 3.2 (Māori) and 3.5 (Pacific people) antibiotic dispensings/1,000 population/day.

If approximately 50% of current dispensing for non-Māori and non-Pacific people is inappropriate, then the estimated rate of appropriate dispensing for these people is approximately 1.5 (50% X 3.02) antibiotic dispensings/1,000 population/day, a rate similar to the current national dispensing rate in Denmark. The rate of appropriate antibiotic dispensing for Māori and Pacific people may therefore be estimated as approximately 2.5 (1.66 X 1.5) antibiotic dispensings/1,000 population/day, significantly lower than the current rates of 3.2 (Māori) and 3.5 (Pacific people) antibiotic dispensings/1,000 population/day.

We believe that Māori and Pacific people currently do “suffer from double jeopardy, being harmed by both over-prescribing and under-prescribing” as Metcalfe et al suggest.1 Both under- and over-prescribing contribute to health inequities in these ethnic groups. The higher proportion of staphylococcal disease in Māori and Pacific people caused by methicillin-resistant Staphylococcus aureus (MRSA)15 is likely to be in part a consequence of over-prescribing of antibiotics for Māori and Pacific people, while their higher rates of admission to hospital for infectious diseases6–8 are strongly suggestive of harm arising from under-prescribing of antibiotics. Therein lies the challenge with antimicrobial stewardship programmes in New Zealand. As we suggested in our previous article,2 we must reduce our rates of inappropriate antibiotic prescribing, while increasing our rates of appropriate antibiotic prescribing. The need to reduce inappropriate antibiotic prescribing is not just limited to non-Māori and non-Pacific people since unnecessary antibiotics should not be prescribed for any patient. The need to increase appropriate antibiotic prescribing is greatest in Māori and Pacific people. Therefore, we reiterate our previous recommendation that antimicrobial stewardship programmes should be sufficiently nuanced to not only reduce rates of inappropriate prescribing but also to increase rates of treatment for infections that do require antimicrobial therapy. We welcome further commentary on how this delicate but important balance can be achieved in an equitable manner across all population groups in New Zealand.

Summary

Abstract

Aim

Method

Results

Conclusion

Author Information

Mark Thomas, Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland; Naomi Whyler, Infectious Diseases, Auckland City Hospital, Auckland; Andrew Tomlin, Best Practice Advocacy Centre, Dunedin; Murray Tilyard Best Practice Advocacy Centre, Dunedin.

Acknowledgements

Correspondence

Associate Professor Mark Thomas, Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, 85 Park Rd, Grafton, University of Auckland, Auckland.

Correspondence Email

mg.thomas@auckland.ac.nz

Competing Interests

Nil.

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