Trends, demographics and disparities in outpatient antibiotic consumption in New Zealand: a national study.

OBJECTIVES: Knowledge of the patterns of antibiotic consumption within a population provides valuable information on when, where and to whom antibiotics are prescribed. Such knowledge is critical in informing possible public health interventions to reduce inappropriate antibiotic use. The aims of this study were to (i) determine national patterns of antibiotic consumption, including assessment of seasonal variation in prescribing, and (ii) explore potential associations between antibiotic consumption and patient characteristics, such as age, sex and ethnicity. METHODS: Data on all subsidized antibiotic dispensing in New Zealand between 1 January 2006 and 31 December 2014 were obtained and stratified according to age, sex and ethnicity. Antibiotic dispensing was expressed as the number of DDDs per 1000 population per day (DID). RESULTS: Total antibiotic consumption in New Zealand increased by 49% from 17.3 DID in 2006 to 25.8 DID in 2014. The increase in antibiotic consumption occurred in all ages and amongst all ethnic groups. The use of extended-spectrum penicillins, which almost doubled in the study period, made a major contribution to the overall increase and was highest in young children and in Pacific peoples. Consumption of quinolones increased early in the study period and then declined from 2011 onwards. CONCLUSIONS: Future work should focus on identifying the appropriateness of antibiotic prescribing, particularly for penicillin prescribing in Pacific peoples and children, and on both reducing unwarranted antibiotic use and improving antibiotic selection when therapy is indicated.

Reactive arthritis incidence in a community cohort following a large waterborne campylobacteriosis outbreak in Havelock North, New Zealand.

OBJECTIVES: In August 2016, Campylobacter spp contaminated an untreated reticulated water supply resulting in a large-scale gastroenteritis outbreak affecting an estimated 8320 people. We aimed to determine the incidence of probable reactive arthritis (ReA) cases in individuals with culture-confirmed campylobacteriosis (CC), self-reported probable campylobacteriosis (PC) and those reporting no diarrhoea (ND). DESIGN: We conducted a retrospective cohort study to identify incidence of probable ReA cases. We identified cases with new ReA symptoms using an adapted acute ReA (AReA) telephone questionnaire. Those reporting ≥1 symptom underwent a telephone interview with the study rheumatologist. Probable ReA was defined as spontaneous onset of pain suggestive of inflammatory arthritis in ≥1 previously asymptomatic joint for ≥3 days occurring ≤12 weeks after outbreak onset. SETTING: Population-based epidemiological study in Havelock North, New Zealand. PARTICIPANTS: We enrolled notified CC cases with gastroenteritis symptom onsets 5 August 2016-6 September 2016 and conducted a telephone survey of households supplied by the contaminated water source to enrol PC and ND cases. RESULTS: One hundred and six (47.3%) CC, 47 (32.6%) PC and 113 (34.3%) ND cases completed the AReA telephone questionnaire. Of those reporting ≥1 new ReA symptom, 45 (75.0%) CC, 13 (68.4%) PC and 14 (82.4%) ND cases completed the rheumatologist telephone interview. Nineteen CC, 4 PC and 2 ND cases developed probable ReA, resulting in minimum incidences of 8.5%, 2.8% and 0.6% and maximum incidences of 23.9%, 12.4% and 2.15%. DISCUSSION: We describe high probable ReA incidences among gastroenteritis case types during a very large Campylobacter gastroenteritis outbreak using a resource-efficient method that is feasible to employ in future outbreaks.