Bayesian structural time series, an alternative to interrupted time series in the right circumstances.

OBJECTIVES: Compare two approaches to analyzing time series data-interrupted time series with segmented regression (ITS-SR) and Bayesian structural time series using the CausalImpact R package (BSTS-CI)-highlighting advantages, disadvantages, and implementation considerations. STUDY DESIGN AND SETTING: We analyzed electronic health records using each approach to estimate the antibiotic prescribing reduction associated with an educational program delivered to Australian primary care physicians between 2012 and 2017. Two outcomes were considered: antibiotics for upper respiratory tract infections (URTIs) and antibiotics of specified formulations. RESULTS: For URTI indication prescribing, average monthly prescriptions changes were estimated at -4,550; (95% confidence interval, -5,486 to -3,614) and -4,270; (95% credible interval, -5,934 to -2,626) for ITS-SR and BSTS-CI, respectively. Similarly for specified formulation prescribing, monthly average changes were estimated at -7,923; (95% confidence interval, -15,887 to 40) for ITS-SR and -20,269; (95% credible interval, -25,011 to -15,635) for BSTS-CI. CONCLUSION: Differing results between ITS-SR and BSTS-CI appear driven by divergent explanatory and outcome series trends. The BSTS-CI may be a suitable alternative to ITS-SR only if the explanatory series represent the secular trend of the outcome series before the intervention and are equally affected by exogenous or confounding factors. When appropriately applied, BSTS-CI provides an alternative to ITS with more readily interpretable Bayesian effect estimates.

Effectiveness of Influenza Vaccination in Reducing Subsequent Antibiotic Prescribing in Young Children Attending Australian General Practices-A Case-Control Study.

BACKGROUND: Vaccination against influenza may reduce antibiotic use, but data are limited and imprecise. METHODS: We conducted a case-control study using deidentified data from a large national primary care database to evaluate antibiotic prescribing changes following influenza vaccination in children 1-4 years old attending primary care in the Australian 2018 and 2019 influenza seasons. Cases were prescribed ß-lactam or macrolide antibiotics during the influenza season and controls were not. Influenza vaccination was documented in the medical records. Adjusted odds ratios for antibiotic prescribing according to influenza vaccination status were estimated using generalized estimating equations, controlling for age, asthma diagnosis, other vaccinations, practice visit frequency, and attendance week. RESULTS: In 2018, 11 282 cases and 32 020 controls were eligible, and in 2019, 12 705 cases and 36 858 controls. Antibiotic prescriptions were less likely in vaccinated participants in 2018 (aOR, 0.65; 95% CI, 0.62-0.69) and 2019 (aOR, 0.78; 95% CI, 0.73-0.82) and did not vary by age, the number of GP visits, or prior prescribing of antibiotics. In the subgroup of children vaccinated in the preceding season, influenza vaccination was not associated with a reduction in antibiotic use (2018-aOR, 1.12; 95% CI, 0.90-1.39; 2019-aOR, 1.30; 95% CI, 1.16-1.46). From our estimates, potentially 100 000 antibiotic prescriptions could be avoided annually in Australia if all children in this age range were vaccinated. CONCLUSIONS: Influenza vaccination may substantially reduce antibiotic prescribing among young children. This effect should be considered in the overall assessment of the costs and benefits of childhood influenza vaccination programs.

Characteristics of patients aged 50–74 years with a request for an immunochemical faecal occult blood test in the Australian general practice setting.

Objective To support improving participation in the National Bowel Cancer Screening Program (NBCSP), we aimed to identify Medicare-subsidised test requests for immunochemical faecal occult blood tests (FOBT) in Australian general practice for patients aged 50-74 years, eligible for the NBCSP, and describe sociodemographics, risk factors, indications and outcomes. Methods A cross-sectional study was conducted using de-identified data from 441 Australian general practice sites in the MedicineInsight database, recorded from 1 January 2018 to 31 December 2019. Results Of the 683 625 eligible patients, 45 771 (6.7%) had a record of a general practitioner (GP)-requested FOBT, either to aid diagnosis in symptomatic patients, or for screening; 144 986 (21.2%) patients had only an NBCSP FOBT. A diagnosis of polyps, gastrointestinal inflammatory condition or haemorrhoids, or a referral to a gastroenterologist or general surgeon, was more commonly recorded in the 6 months after a GP-requested FOBT than after an NBCSP FOBT. Uptake of NBCSP FOBTs was lower among those with obesity, high alcohol consumption and current smokers, who are at higher risk of bowel cancer. Conclusions This study describes the patient characteristics, reasons and outcomes associated with GP-requested FOBTs, identifies under-screened population sub-groups, and suggests involvement of GPs to improve participation in the NBCSP.

Patterns of real-world opioid prescribing in Australian general practice (2013-18).

Little is known about private-market opioid prescribing and how Australian opioid policies impact prescribing across public and private markets in Australia. We aimed to investigate publicly subsidised and private-market opioid prescribing from 2013 to 2018. We used prescribing records from MedicineInsight, an Australian primary care database, to examine trends in prescriptions for non-injectable opioid formulations from October 2013 to September 2018. We examined annual opioid prescribing trends overall, by opioid agent, and by market (public and private). We further examined patterns of fentanyl patch prescribing focusing on co-prescribed medicines and use in opioid-naïve patients. Opioids accounted for 8% of all prescriptions over the study period and 468 893 patients were prescribed at least one opioid of interest. Prescribing rates for oxycodone/naloxone and tapentadol increased, whereas those for fentanyl patches, morphine and single-agent oxycodone decreased over the study period. Private-market prescribing rates of codeine (schedule 4) increased notably following its up-scheduling to prescription-only status. Among patients prescribed fentanyl patches, 29% were potentially opioid-naïve and 49% were prescribed another opioid on the same day. The private-medicines market is a small but growing component of opioid use in Australia and one way in which prescribers and patients can avoid access restrictions in the public market for these medicines. Although fentanyl patch prescribing declined, there is room for improvement in prescribing fentanyl patches among opioid-naïve patients, and co-prescribing of fentanyl patches with other sedatives.

The changing characteristics of patients with chronic hepatitis C prescribed direct acting antiviral medicines in general practice since listing of the medicines on the Australian Pharmaceutical Benefits Scheme.

BACKGROUND AND AIM: The primary objective of this study was to determine whether the characteristics of patients prescribed direct acting antiviral (DAA) medicines have changed since initial listing of the medicines on the Australian Pharmaceutical Benefits Scheme (PBS). METHODS: A cross-sectional study was conducted using data from MedicineInsight, an Australian database of general practice electronic health records, from March 2016 to August 2018. We compared sociodemographic, comorbidity, and clinical characteristics of patients aged at least 18 years who were prescribed at least one DAA in the first 4 months of PBS listing in 2016 with those prescribed at least one DAA in 2018. RESULTS: There were 2251 eligible adult patients prescribed a DAA during the study period, 62% were men and 59% were aged 50 years and older. Patients prescribed DAA medicines initially were older (aged ≥50 years: 67.9% vs 49.3%; P < 0.001), and more likely to have liver cirrhosis (14.2% vs 8.4%; P = 0.01) and an aminotransferase to platelet ratio index (APRI) score >1 (20.4% vs 8.9%; P < 0.001) than those prescribed DAA medicines in 2018. A greater proportion of patients in regional/remote (46.5% vs 35.6%; P < 0.001) and socioeconomically disadvantaged areas (44.4% vs 34.5%; P = 0.003) accessed treatment in 2018 compared with 2016. CONCLUSIONS: Despite evidence of decreasing uptake of DAA medicines across Australia, this study indicates broadened uptake among younger age groups and those residing in regional/remote and socioeconomically disadvantaged areas since 2016. While uptake of DAA medicines in some population subgroups appears to have improved, continuous efforts to improve uptake across the Australian population are essential.

Pregabalin prescribing patterns in Australian general practice, 2012-2018: a cross-sectional study.

BACKGROUND: In 2013 pregabalin was subsidised by Australia's Pharmaceutical Benefits Scheme (PBS) for neuropathic pain. Since the subsidy, pregabalin prescribing has been increasing in Australia and so has related harm. There are concerns it is being prescribed for indications other than neuropathic pain, which have little evidence of efficacy. AIM: To describe pregabalin prescribing in Australian general practice. DESIGN & SETTING: A cross-sectional study of patients attending 445 general practice sites in the national MedicineInsight database from March 2012-February 2018. METHOD: The following aspects were calculated: the proportion of prescriptions that were for pregabalin per year; the prevalence of pain conditions in patients prescribed pregabalin; and same-day prescribing of pregabalin with opioids or benzodiazepines. RESULTS: Prescribing increased from 13 per 10 000 to 104 per 10 000 prescriptions between 2012-2013 and 2017-2018. A total of 1 891 623 patients were identified of whom 114 123 (6.0%) were prescribed pregabalin; 49.7% (n = 56 772) had a recorded diagnosis of neuropathic pain. Among people prescribed pregabalin without a recorded diagnosis of neuropathic pain, 43.5% (n = 24 927) had a diagnosis of back problems, 8.8% (n = 5073) chronic pain, and 26.4% (n = 30 146) had no pain diagnosis. Pregabalin was prescribed the same day as an opioid to 38.1% of patients (95% confidence interval [CI] = 37.1% to 39.1%) and a benzodiazepine to 13.1% of patients (95% CI = 12.5% to 13.7%). Patients with a diagnosis of chronic pain had the highest rate of same-day prescribing of pregabalin with an opioid (70.4%, 95% CI = 68.9% to 71.9%) or a benzodiazepine (25.8%, 95% CI = 24.2% to 27.4%) CONCLUSION: Substantial increases in pregabalin prescribing were identified in Australian general practice, but only half of patients had a neuropathic pain diagnosis recorded, the only approved indication for subsidy. High rates of same-day prescribing with opioids and benzodiazepines may put patients at increased risk of harm.

Impact of NPS MedicineWise general practitioner education programs and Choosing Wisely Australia recommendations on prescribing of proton pump inhibitors in Australia.

BACKGROUND: This study evaluated the impact of multifaceted NPS MedicineWise programs that targeted all general practitioners (GPs) in Australia in 2009 and 2015 with the aim of reducing unnecessary prescribing of proton pump inhibitors (PPIs) and encouraged stepping down to a lower strength PPI or to discontinue treatment. The 2015 intervention coincided with the release of Choosing Wisely Australia recommendations from the Royal Australian College of General Practitioners (RACGP). METHODS: Outcome measures included monthly dispensing rates of different strength PPIs prescribed by GPs to concessional patients in Australia. All PPIs were categorized according to the May 2019 revised classifications for standard and low strength PPIs except for esomeprazole 40 mg which was classified as a standard strength and esomeprazole 20 mg as low strength for this analysis. Time series analyses was conducted of the dispensing rates of PPI prescriptions for concessional patients between January 2006 and June 2016 using the Pharmaceutical Benefits Scheme (PBS) and Medicare Benefits Schedule (MBS) databases in Australia. Participants were GPs with dispensed PPI prescriptions to concessional patients between January 2006 and June 2016. RESULTS: Following the 2009 NPS MedicineWise program we observed a 6.7% reduction in the expected dispensing rate of standard strength PPIs for concessional patients between April 2006 and March 2015, and an 8.6% reduction between April 2009 and June 2016 following the 2015 program launch. We observed a significant increase of 5.6% in the dispensing rate of low strength PPIs for concessional patients between April 2009 and March 2015, and no significant change in trend following the 2015 program. CONCLUSIONS: The NPS MedicineWise programs were associated with reductions in the dispensing rate of standard strength PPIs by June 2016 and an increase in the dispensing rate of low-strength PPIs by March 2015 although this trend did not continue following the 2015 program. This suggests that GPs are stepping down patients to lower strength PPIs following the educational programs. However, lower strength PPIs are still not the majority of PPIs dispensed in Australian and regular interventions to sustain and improve PPI management by GPs may be warranted.

Prevalence, incidence and management of atopic dermatitis in Australian general practice using routinely collected data from MedicineInsight.

BACKGROUND/OBJECTIVES: The prevalence of atopic dermatitis (AD) has increased significantly in industrialised countries in recent decades but data about the incidence or prevalence of AD in Australia are sparse. We aimed to determine the prevalence and incidence of AD among patients seen in Australian general practice and the use of specified medicines. METHODS: This was a cross-sectional study of 2.1 million patients attending 494 general practices in the MedicineInsight program from 1 January 2017 to 31 December 2018. We assessed the prevalence (lifetime and current), incidence, management and severity of AD. RESULTS: The lifetime (ever diagnosed) prevalence of AD in this general practice population was 16.4% and was greater in females (17.3%) than males (15.3%). One in five patients with AD were classified as having moderate-to-severe disease. Prevalence over the last two years was 6.3%. The incidence of AD in 2018 was 2.0% and was greater in females (2.2%) and for patients aged 0-4 years (3.9%). Patients with AD had an increased risk of insomnia, anxiety and depression, compared to those with no recorded AD. For AD patients, topical corticosteroids were the most commonly prescribed AD medication (36.5%) and topical calcineurin inhibitors the least (0.1%), with systemic corticosteroids (15.6%) more commonly prescribed than other immunosuppressants (0.9%). CONCLUSIONS: Our findings provide important insights into the epidemiology of AD and its management in Australian general practice. This information is likely to be useful in planning effective interventions to support GPs in the optimal management of patients with AD.

A national intervention to reduce imaging for low back pain by general practitioners: a retrospective economic program evaluation using Medicare Benefits Schedule data.

BACKGROUND: The overuse of diagnostic imaging for low back pain (LBP) in Australia results in unnecessary cost to the health system and, for patients, avoidable exposure to radiation. The 2013 NPS MedicineWise LBP program aimed to reduce unnecessary diagnostic imaging for non-specific acute LBP in the Australian primary care setting. The LBP program delivered referral pattern feedback, a decision support tool and patient information to 19,997 (60%) of registered Australian general practitioners (GPs). This study describes the findings from evaluation of the effectiveness of the 2013 LBP program at reducing X-ray and computed tomography (CT) scans of the lower back, and the financial costs and benefits of the program to the government funder. METHODS: The effectiveness of the 2013 LBP program was evaluated using population-based time-series analysis of administrative claims data of Medicare Benefits Schedule (MBS) funded X-ray and CT scan services of the lower back. The CT scan referral trend of non-GP health professionals was used as an observational control group in a Bayesian structural time-series model. A retrospective cost-benefit analysis and cost-effectiveness analysis was conducted using program costs from organisational records and reimbursement data from the MBS. RESULTS: The 2013 NPS MedicineWise LBP program was associated with a statistically significant 10.85% relative reduction in the volume of CT scans of the lumbosacral region, equating to a cost reduction to the MBS of AUD$11,600,898. The best available estimate of program costs was AUD$141,154. Every dollar of funding spent on the 2013 LBP program saved AUD$82 of funding to the MBS for CT scan reimbursements. Therefore, from the perspective of the Australian Government Department of Health, the 2013 LBP program was cost saving. The program cost AUD$2.82 per CT scan averted in comparison to the scenario of no program. No association between the 2013 NPS MedicineWise LBP program and the volume of X-ray items on the MBS was observed. CONCLUSIONS: The 2013 NPS MedicineWise LBP program reduced CT scan referral by GPs, in line with the program's messages and clinical guidelines. Reducing this low-value care produced savings to the health system that exceeded the costs of program implementation.

NPS MedicineWise: 20 years of change.

The cost and potential harms of medicines and other health technologies are issues of concern for governments and third party payers of health care. Various means have been demonstrated to promote appropriate evidence-based use of these technologies as a way to reduce waste and unintended variation. Since 1998, Australia has had a national organisation responsible for large scale programs to address safe, effective and cost effective use of health technologies. This article reviews 20 years of experience for NPS MedicineWise (NPS). NPS provides evidence-based information to health professionals and consumers using interventions that have been shown to be effective. A mix of academic detailing, audit and feedback and interactive learning is built into national programs designed to improve the use of medicines and medical tests. The target audiences have typically been general practitioners, pharmacists and nurses in primary care. Consumer programs, including mass media campaigns have supported the work with health professionals. NPS receives most of its income from the Australian Government and in return it is required to show saving for the Pharmaceutical Benefits Scheme and the Medical Benefits Schedule. Since 1998, total savings of AUD 1096.62 million have been demonstrated. In addition, changes in knowledge and attitudes, changes in prescribing and test ordering behaviours and improvements in health outcomes have been shown through annual evaluations.

Relationship between antimicrobial-resistance programs and antibiotic dispensing for upper respiratory tract infection: An analysis of Australian data between 2004 and 2015.

Objective NPS MedicineWise aims to ensure that medicines are prescribed and used in a manner consistent with current evidence-based best practice. A series of nationwide educational and advertising interventions for general practitioners and consumers were implemented in Australia between 2009 and 2015 with the aim of reducing antibiotic prescriptions for upper respiratory tract infections (URTIs). The work described in this paper quantifies the change in antibiotic dispensing following these interventions. Methods Antibiotic dispensing data between 2004 and 2015 were obtained from a national claims database. A Bayesian structural time series model was used to forecast a series of antibiotic dispensing volumes expected to have occurred if the interventions had not taken place. These were compared with the volumes that were actually observed to estimate the intervention effect. Results On average, 126,536 fewer antibiotics were dispensed each month since the intervention programs began in 2009 (95% Bayesian credible interval = 71,580-181,490). This change represents a 14% total reduction in dispensed scripts after the series of intervention programs began in 2009. Conclusions Continual educational intervention programs that emphasise the judicious use of antibiotics may effectively reduce inappropriate prescribing of antibiotics for the treatment of URTIs at a national level.