Long-term prescribed opioid use after hospitalization or emergency department presentation among opioid naïve adults (2014-2020)-A population-based descriptive cohort study.

AIMS: The aim of this work is to describe opioid initiation and long-term use after emergency department (ED) visits or hospitalizations in New South Wales, Australia, by patient, admission and clinical characteristics. METHODS: This is a population-based cohort study, including all hospitalizations and ED visits between 2014 and 2020, linked to medicine dispensings, deaths and cancer registrations (Medicines Intelligence Data Platform), among adults with no opioid dispensings in the previous year. Outcome measures were opioid initiations (dispensed within 7 days of discharge) and long-term use (90 days of continuous exposure, 90-270 days after initiation). RESULTS: The cohort included 16 153 096 admissions by 4.2 million opioid-naïve adults; 39.0% were ED presentations without hospital admission, 16.8% hospital admissions via ED and 44.2% direct hospital admissions. Opioids were initiated post-discharge for 6.2% of ED, 8.3% of hospital via ED and 10.0% of direct hospital admissions; of these 1.0%, 2.5% and 0.5% progressed to long-term opioid use, respectively. Initiation was lowest in obstetric admissions without surgery (1.0%), and highest among trauma admissions (25.4%), obstetric admissions with surgical intervention (19.8%) and non-trauma surgical admissions (12.0%). Long-term use was highest among medical admissions via ED (3.5%), trauma admissions (2.3%) and ED alone (1.0%). From 2014 to 2020, overall opioid initiations decreased 16% from 8.7% to 7.2%, and long-term opioid use decreased 33% from 1.3% to 0.8%. CONCLUSIONS: Both opioid initiation and long-term use decreased over time; however, the higher rates of long-term use following trauma, and medical admissions via ED, warrant further surveillance. Strategies supporting appropriate prescribing and access to multidisciplinary pain services will facilitate best practice care.

Oxycodone initiation in Australia (2014-2018): Sociodemographic factors and preceding health service use.

AIMS: Oxycodone is the most commonly prescribed strong opioid in Australia. This study describes health service antecedents and sociodemographic factors associated with oxycodone initiation. METHODS: Population-based new user cohort study linking medicine dispensings, hospitalizations, emergency department visits, medical services and cancer notifications from New South Wales (NSW) for 2014-2018. New users had no dispensings of any opioid in the preceding year. We analysed health service use in the 5 days preceding initiation and proportion of people on treatment over 1 year and fitted an area-based, multivariable initiation model with sociodemographic covariates. RESULTS: Oxycodone accounted for 30% of opioid initiations. Annually, 3% of the NSW population initiated oxycodone, and 5-6% were prevalent users; the new user cohort comprised 830 963 people. Discharge from hospital (39.3%), therapeutic procedures (21.4%) and emergency department visits (19.7%) were common; a hospital admission for injury (6.0%) or a past-year history of cancer (7.2%) were less common. At 1 year after initiation, 4.6% of people were using oxycodone. In the multivariable model, new use of oxycodone increased with age and was higher for people outside major cities, for example, an incidence rate ratio of 1.43 (95% confidence interval 1.36-1.51) for inner regional areas relative to major cities; there was no evidence of variation in rates of new use by social disadvantage. CONCLUSION: About half of new oxycodone use in NSW was preceded by a recent episode of hospital care or a therapeutic procedure. Higher rates of oxycodone initiation in rural and regional areas were not explained by sociodemographic factors.

The impact of tightened prescribing restrictions for PBS-subsidised opioid medicines and the introduction of half-pack sizes, Australia, 2020-21: an interrupted time series analysis.

OBJECTIVES: To evaluate the impact of the tightened Pharmaceutical Benefits Scheme (PBS) prescribing rules for immediate release (IR) and controlled release (CR) opioid medicines (1 June 2020), which also eliminated repeat dispensing without authorisation for codeine/paracetamol and tramadol IR and introduced half-pack size item codes for IR formulations. DESIGN, SETTING: Population-based interrupted time series analysis of PBS dispensing data claims for a 10% sample of PBS-eligible residents and IQVIA national opioid medicine sales data (PBS-subsidised and private prescriptions), 28 May 2018 - 6 June 2021. MAIN OUTCOME MEASURES: Mean amount of PBS-subsidised opioid medicines dispensed per day and mean overall amount sold per day - each expressed as oral morphine equivalent milligrams (OME) - overall, by formulation type (IR, CR), and by specific formulation. RESULTS: During the twelve months following the PBS changes, daily PBS-subsidised opioid medicine dispensing was 81 565 OME lower (95% CI, -106 146 to -56 984 OME) than the mean daily level for 2018-20, a decline of 3.8% after adjusting for the pre-intervention trend; the relative reduction was greater for IR (8.4%) than CR formulations (2.6%). Total daily sales of all, IR formulation, and CR formulation opioid medicines did not change significantly after the PBS changes. Repeat dispensing of prescriptions comprised 7.4% of PBS-subsidised opioid dispensing before 1 June 2020, and 1.3% after the changes. Half-pack sizes comprised 8.4% of PBS-subsidised IR opioid medicine dispensing and 2.8% of all opioid medicines sold in the twelve months after the PBS changes. CONCLUSIONS: The introduction of new PBS rules for subsidised opioid medicines was followed by a decline in PBS-subsidised dispensing. Some people may have bypassed the new restrictions by switching to private prescriptions, but our findings suggest that opioid medicine use in Australia declined as a result of the new restrictions.

Prevalence and Persistence of Prescription Opioid Use Following Hospital Discharge After Childbirth: An Australian Population-Based Cohort Study.

BACKGROUND: Opioid analgesics are used for acute postpartum pain relief but carry risks, including persistent long-term opioid use. Our primary objective was to estimate the prevalence of persistent use following hospital discharge after childbirth. METHODS: We conducted a population-based cohort study of women discharged from public or private hospitals in New South Wales, Australia, between 2012 and 2018 following vaginal birth (VB) or cesarean delivery (CD). We used linked hospitalization and medicine dispensing data to calculate the prevalence of opioid use within 14 days of hospital discharge for childbirth using an external estimate of the total number of hospital admissions for childbirth per year as the denominator. Among women dispensed an opioid postdischarge, we estimated the prevalence of persistent use defined as ≥3 dispensings between 30- and 365-days postdischarge. To calculate the odds of persistent opioid use, we performed a series of logistic regressions each including a single characteristic of interest. Included characteristics were maternal and birth characteristics, maternal medical conditions, prior use of certain medicines, and the initial opioid dispensed following discharge for childbirth. RESULTS: The final cohort comprised of 38,832 women who were dispensed an opioid in the 14 days following discharge after childbirth. Between 2012 and 2018, the prevalence of opioid use was increased following CD (public hospital 16.6%-21.0%; private hospital 9.8%-19.5%) compared with VB (public hospital 1.5%-1.5%; private hospital 1.2%-1.4%) and was higher following discharge from public hospitals compared with private. The most commonly dispensed opioids following discharge for childbirth were oxycodone (44.8%; 95% confidence interval [CI], 44.3-45.3), codeine (42.1%; 95% CI, 41.6-42.6), and tramadol (12.9%; 95% CI, 12.6-13.2). Among women dispensed an opioid, the prevalence of persistent opioid use was 5.4% (95% CI, 5.1-5.6). This prevalence was 11.4% (95% CI, 10.5-12.3) following a VB as compared with 4.3% (95% CI, 4.1-4.6) among those who underwent a CD ( P < .001). Characteristics associated with persistent opioid use included smoking during pregnancy, age <25 years, living in remote areas, discharged from a public hospital, history of opioid use disorder, other substance use disorder, mental health diagnosis, or prior use of prescription opioids, nonopioid analgesics, or benzodiazepines. CONCLUSIONS: The results of this cohort study indicate that Australian women have a higher prevalence of opioid use following CD compared to VB. One in 19 women dispensed an opioid postdischarge used opioids persistently. Careful monitoring of opioid therapy following childbirth is warranted, particularly among women with characteristics we identified as high risk for persistent opioid use.

A data-informed approach using individualised dispensing patterns to estimate medicine exposure periods and dose from pharmaceutical claims data.

Pharmaceutical claims data are often used as the primary information source to define medicine exposure periods in pharmacoepidemiological studies. However, often critical information on directions for use and the intended duration of medicine supply are not available. In the absence of this information, alternative approaches are needed to support the assignment of exposure periods. This study summarises the key methods commonly used to estimate medicine exposure periods and dose from pharmaceutical claims data; and describes a method using individualised dispensing patterns to define time-dependent estimates of medicine exposure and dose. This method extends on important features of existing methods and also accounts for recent changes in an individual's medicine use. Specifically, this method constructs medicine exposure periods and estimates the dose used by considering characteristics from an individual's prior dispensings, accounting for the time between prior dispensings and the amount supplied at prior dispensings. Guidance on the practical applications of this method is also provided. Although developed primarily for application to databases, which do not contain duration of supply or dose information, use of this method may also facilitate investigations when such information is available and there is a need to consider individualised and/or changing dosing regimens. By shifting the reliance on prescribed duration and dose to determine exposure and dose estimates, individualised dispensing information is used to estimate patterns of exposure and dose for an individual. Reflecting real-world individualised use of medicines with complex and variable dosing regimens, this method offers a pragmatic approach that can be applied to all medicine classes.

"Frustrated with the whole system": a qualitative framework analysis of the issues faced by people accessing health services for chronic pain.

BACKGROUND: Chronic non-cancer pain (CNCP) is complex and often requires multimodal management comprising of both pharmacological and non-pharmacological treatments. To inform delivery of CNCP management, it is important to understand how current health services providing non-pharmacological treatments are accessed by exploring the experiences of people attempting to access services. In doing so, this study sought to explore the underlying drivers of service access barriers. METHODS: This study explored the experiences of Australians accessing services for CNCP using semi-structured telephone interviews undertaken between 01 October 2020 and 31 March 2021. Thematic analysis was guided by Levesque et al.'s 2013 conceptual framework of access to health care, with emerging themes mapped to five dimensions of accessibility and corresponding abilities of consumers: Approachability/Ability to perceive; Acceptability/Ability to seek; Availability and Accommodation/Ability to reach; Affordability/Ability to pay; and Appropriateness/Ability to engage. RESULTS: The 26 participants (aged 24-78 years, 22 female) reported accessing a range of services including general practitioners (GP), allied health services, and specialised pain clinics, for a variety of conditions. Three themes were mapped to accessibility dimensions (in brackets): 'GP as guide or gatekeeper' (Approachability); 'Outside of my control' (Availability and Accommodation; Affordability); and 'Services aren't always good enough' (Appropriateness). A fourth identified theme illustrated how participants responded to encountering these barriers: 'Leading my own pain management'. Participant experiences suggest problems with the translation of contemporary pain management principles into practice, including continued application of biomedical health models as opposed to the biopsychosocial model, and demonstrate systemic issues with service delivery, including a lack of benchmarking of specialised services. CONCLUSIONS: The identified themes highlight several evidence-to-practice gaps in the delivery of health services for people with CNCP in Australia. To address these gaps, there is a need for improved clinician training, increased investment in specialised pain services, and development of clear primary care pathways for CNCP management for evidence-based multimodal pain management to be accessible and equitable.

Variations in Long-term Opioid Therapy Definitions: A Systematic Review of Observational Studies Using Routinely Collected Data (2000-2019).

Routinely collected data have been increasingly used to assess long-term opioid therapy (LTOT) patterns, with very little guidance on how to measure LTOT from these data sources. We conducted a systematic review of studies published between January 2000 and July 2019 to catalogue LTOT definitions, the rationale for definitions and LTOT rates in observational research using routinely collected data in nonsurgical settings. We screened 4056 abstracts, 210 full-text manuscripts and included 128 studies, mostly from the United States (81%) and published between 2015 and 2019 (69%). We identified 78 definitions of LTOT, commonly operationalised as 90 days of use within a year (23%). Studies often used multiple criteria to derive definitions (60%), mostly based on measures of duration, such as supply days/days of use (66%), episode length (21%) or prescription fills within specified time periods (12%). Definitions were based on previous publications (63%), clinical judgment (16%) or empirical data (3%); 10% of studies applied more than one definition. LTOT definition was not provided with enough details for replication in 14 studies and 38 studies did not specify the opioids evaluated. Rates of LTOT within study populations ranged from 0.2% to 57% according to study design and definition used. We observed a substantial rise in the last 5 years in studies evaluating LTOT with large variability in the definitions used and poor reporting of the rationale and implementation of definitions. This variation impacts on research reproducibility, comparability of findings and the development of strategies aiming to curb therapy that is not guideline-recommended.

Clinical correlates and outcomes associated with pregabalin use among people prescribed opioids for chronic non-cancer pain: A five-year prospective cohort study.

AIMS: Pregabalin has become widely used as an alternative to opioids in treating certain types of chronic non-cancer pain, but few studies have examined its clinical efficacy outside trials. We address this gap by examining the utilization, correlates and clinical outcomes of pregabalin use among an Australian community-based cohort of people prescribed opioids for chronic non-cancer pain. METHODS: Through a five-year prospective cohort study (n = 1514) we examined associations between pregabalin use and pain severity and interference, mental health, opioid dose and past month use of ambulance and emergency department services. We used fixed-effects regression models to examine within-participant differences, and random-effects regression models to examine within- and between-participant differences in clinical outcomes. RESULTS: In an analysis of cases with complete data over five-years (n = 896), the prevalence of pregabalin use ranged from 16% at cohort entry to 29% at 36- and 48-months, and 46% reported pregabalin use at any time during the five years. Pregabalin use was associated with greater pain severity and interference and greater use of high-risk opioid doses (>90 oral morphine equivalents/day). Pregabalin use was not associated with changes in mental health symptoms, ambulance or emergency department attendance in the fixed or random effects models. CONCLUSIONS: Pregabalin use was common, but for most people use was not associated with clinically meaningful improvements in pain or functioning.

New psychoactive substances: challenges for drug surveillance, control, and public health responses.

The rapid emergence since the mid-2000s of a large and diverse range of substances originally designed as legal alternatives to more established illicit drugs (pragmatically clustered and termed new psychoactive substances; [NPS]) has challenged traditional approaches to drug monitoring, surveillance, control, and public health responses. In this section of the Series, we describe the emergence of NPS and consider opportunities for strengthening the detection, identification, and responses to future substances of concern. First, we explore the definitional complexity of the term NPS. Second, we describe the origins and drivers surrounding NPS, including motivations for use. Third, we summarise evidence on NPS availability, use, and associated harms. Finally, we use NPS as a case example to explore challenges and opportunities for future drug monitoring, surveillance, control, and public health responses. We posit that the current means of responding to emerging substances might no longer be fit for purpose in a world in which different substances can be rapidly introduced, and where people who use drugs can change preferences on the basis of market availability.

Changes in sales of analgesics to pharmacies after codeine was rescheduled as a prescription only medicine.

OBJECTIVE: To investigate changes in sales to pharmacies of over-the-counter (OTC) and prescription analgesics, cold and flu products, and cough suppressants after the rescheduling of codeine as a prescription only medicine in February 2018. DESIGN: Interrupted time series analysis of sales to pharmacies. SETTING: Pharmaceutical sales to community pharmacies in Australia, March 2015 - March 2019. The period January 2017 (month after rescheduling was announced) to January 2018 (month before rescheduling was implemented) was excluded from the time series analysis. MAIN OUTCOME MEASURES: Monthly pack and tablet sales per 10 000 population of OTC and prescription analgesics, cold and flu products, and cough suppressants. RESULTS: During 2016, 7586 packs and 248 127 tablets of OTC codeine per 10 000 population were sold to pharmacies; in the 14 months after rescheduling, a small level increase in monthly prescription codeine sales was evident (2247 tablets/capsules per 10 000 population; 95% CI, 1231-3264 per 10 000 population). Monthly OTC analgesic sales increased by 258 (95% CI, 151-365) packs per 10 000 population and 37 856 (95% CI, 26 143-49 569) tablet/capsules per 10 000 population. Monthly sales of single ingredient paracetamol (41 415 [95% CI, 31 374-51 456] tablets/capsules per 10 000 population), ibuprofen (1392 [95% CI 916-1868] tablets/capsules per 10 000 population), paracetamol/ibuprofen (1618 tablets [95% CI, 1567-1669] tablets/capsules per 10 000 population), and other paracetamol combinations (233 [95% CI, 112-353] tablets/capsules per 10 000 population) all increased, but not those of prescription analgesic products not containing codeine. Rises for OTC cold/flu products containing the opioid derivative dextromethorphan were small; sales of OTC cough suppressants containing opioid derivatives (dextromethorphan, pholcodine, dihydrocodeine) did not change. CONCLUSIONS: The rescheduling of codeine was followed by increased sales to pharmacies of paracetamol, ibuprofen, and paracetamol combination products. While these products carry no risk of dependence, their inappropriate use is also associated with harms that warrant adverse event monitoring.

Prevalence and incidence of prescription opioid analgesic use in Australia.

AIMS: The aims of the current study were to determine the prevalence and incidence of prescription opioid analgesic use in Australia and compare the characteristics of people with and without cancer initiating prescription opioid analgesics. METHODS: A retrospective population-based study was conducted using the random 10% sample of adults who were dispensed prescription opioid analgesics in Australia between July 2013 and June 2017 through the Pharmaceutical Benefits Scheme. Poisson regression was used to calculate rate ratios (RR) for opioid prevalence and incidence. The characteristics of people initiating opioids, including type of opioid initiated, total oral morphine equivalents dispensed, prescriber speciality, medical comorbidities, and past analgesic and benzodiazepine use, were compared for people with and without cancer. RESULTS: Opioid prevalence increased {RR = 1.006 [95% confidence interval (CI) 1.004, 1.008]}, while incidence decreased [RR = 0.977 (95% CI 0.975,0.979)] from 2013/2014 to 2016/2017. There were between 287 677 and 307 772 prevalent users each year. In total, 769 334 adults initiated opioids between 2013/2014 and 2016/2017, and half of these initiations were by general practitioners. Initiation with a strong opioid occurred in 55.8% of those with cancer and 28.2% of those without cancer. CONCLUSION: Rates of opioid use have remained high since 2013, with approximately 3 million adults using opioids and over 1.9 million adults initiating opioids each year. Between 2013 and 2017, opioid prevalence has slightly increased but incidence has decreased. People without cancer account for the majority of opioid use and are more likely to be initiated on short-acting and weak opioids. Initiation of strong opioids has increased over time, reinforcing concerns about increased use and the harms associated with strong opioids in the community.

A population-based study of transdermal fentanyl initiation in Australian clinical practice.

PURPOSE: Although guidelines caution against initiation of transdermal (TD) fentanyl among those who are opioid naïve, there is concern that not all people receive adequate prior opioid exposure. This study examined the percentage of people who are opioid naïve at the time of TD fentanyl initiation in Australia; strengths initiated; and characteristics associated with being opioid naïve. METHODS: This is a national retrospective cohort study derived from a 10% sample of Pharmaceutical Benefits Scheme concessional beneficiaries initiating TD fentanyl between 29 September 2009-31 December 2013. Individuals were deemed opioid naïve if they had no opioid dispensings in the previous 90 days. Logistic regression was used to determine characteristics associated with being opioid naïve, including socio-demographics, likely comorbidities and previous analgesic use. RESULTS: A total of 13,166 people initiated TD fentanyl; 60.4% were female and 76.2% were aged ≥ 65 years. Three in ten (30.4%) were opioid naïve and 63.2% initiated the 12 mcg/h patch. Those who were opioid naïve were more likely to be female (adjusted odds ratio (aOR) 1.35; 95% CI 1.25-1.46), older (aOR 1.85; 95% CI 1.54-2.28 for those ≥ 85 years) and previously dispensed medicines for dementia (aOR 1.37; 95% CI 1.04-1.80). People previously dispensed medicines for cancer were less likely to be opioid naïve (aOR 0.57; 95% CI 0.48-0.67). CONCLUSIONS: Three in ten Australians initiating TD fentanyl are opioid naïve. Our findings suggest that specific patient sub-populations already at increased risk of opioid-related adverse events are not receiving prior opioid treatment before initiation, highlighting the need for greater adherence to current treatment guidelines.

Antidepressant Use Among People Prescribed Opioids for Chronic Noncancer Pain.

OBJECTIVE: Although depression and chronic pain often coexist, few studies have examined antidepressant use among people with pain. This study examines the prevalence and characteristics associated with antidepressant use among people prescribed opioids for chronic noncancer pain (CNCP). DESIGN: Baseline data from a prospective cohort study. SETTING: Australian community. SUBJECTS: A total of 1166 people prescribed opioids for CNCP. METHODS: Baseline data collection consisted of a self-completed seven-day medication diary and telephone interview to collect information on sociodemographic characteristics and mental/physical health using validated questionnaires. Logistic regression was used to examine characteristics associated with antidepressant use, reporting adjusted odds ratios (AORs) and 95% confidence intervals (CIs). RESULTS: Of the 1166 participants, 668 (57.3%) were female, and the median (interquartile range) age was 59 (49-68) years. About half the cohort (N = 637, 54.6%) used antidepressants. Of these, 329 (51.7%) reported moderate to severe depression. Amitriptyline was the most commonly used antidepressant (17.3%). Factors independently associated with antidepressant use were being female (AOR = 1.47, 95% CI = 1.13-1.92), more years lived in pain (AOR = 1.01, 95% CI = 1.00-1.02), and use of nonopioid analgesics (AOR = 1.34, 95% CI = 1.01-1.78), benzodiazepines and related drugs (AOR = 1.84, 95% CI = 1.36-2.49), antiepileptics (AOR = 1.86, 95% CI = 1.38-2.51), and antipsychotics (AOR = 2.15, 95% CI = 1.22-3.77). CONCLUSIONS: Antidepressant use is common among people with CNCP prescribed opioids. Those using antidepressants were more likely to use other psychotropic medicines concurrently, highlighting that they are a high-risk population requiring comprehensive assessment to optimize outcomes and reduce potential harms from polypharmacy.

Predictors of persistent prescription opioid analgesic use among people without cancer in Australia.

AIMS: To identify patterns of opioid analgesic use and determine predictors of persistent opioid use among people without cancer. METHODS: A population-based cohort study of Australians initiating prescription opioids from July 2013 to December 2015 was conducted using data from a random 10% sample of people who accessed medicines through Australia's Pharmaceutical Benefits Scheme. A 12-month retrospective period was used to define opioid initiation, exclude people with cancer and determine comorbidities. Persistent use over 12 months since initiation was identified through group-based trajectory modelling. Odds ratios (OR) and 95% confidence intervals (CIs) for predictors of opioid persistence were estimated using logistic regression. RESULTS: The cohort consisted of 431 963 people without cancer who initiated opioids. A total of 11 323 (2.6%) persistent opioid users were identified. Predictors of persistence included initiation with transdermal formulations (OR 4.2, 95% CI 3.9-4.5), or initiation with total oral morphine equivalents (OME) ≥ 750 mg (3.7, 3.3-4.1), having depression (1.6, 1.5-1.7) or psychotic illness (2.0, 1.9-2.2). Previous dispensing of paracetamol (2.0, 1.9-2.1), pregabalin (2.0, 1.8-2.1) and benzodiazepines (1.53, 1.4-1.6) predicted persistence. Compared to people aged 18-44 years, those ≥75 years were 2.5 (2.3-2.6) times more likely to be persistent users. CONCLUSIONS: Patient-specific characteristics (older age, prior history of mental health comorbidities and use of non-opioid analgesics) and prescriber choice of initial opioid (transdermal formulation and higher total OMEs) were found to strongly predict persistent use. This information may help prescribers target monitoring and early intervention efforts in order to prevent harms associated with the long-term use of opioids.

To what extent do data from pharmaceutical claims under-estimate opioid analgesic utilisation in Australia?

PURPOSE: Although pharmaceutical claims are an essential data source for pharmacoepidemiological studies, these data potentially under-estimate opioid utilisation. Therefore, this study aimed to quantify the extent to which pharmaceutical claims from Australia's national medicines subsidy programs (Pharmaceutical Benefits Scheme [PBS] and Repatriation Schedule of Pharmaceutical Benefits [RPBS]) under-estimate prescription-only and total national opioid utilisation across time and for different opioids. A secondary aim was to examine the impact of the 2012 policy change to record all PBS/RPBS dispensed medicines, irrespective of government subsidy, on the degree of under-estimation. METHODS: Aggregated data on Australian opioid utilisation were obtained for the 2010 to 2014 calendar years, including all single ingredient and combination opioid analgesic preparations available on prescription or over-the-counter (OTC). Total opioid utilisation (oral morphine equivalent kilogrammes) was quantified using sales data from IMS Health and compared with pharmaceutical claims data from the PBS/RPBS. RESULTS: PBS/RPBS claims data did not account for 12.4% of prescription-only opioid utilisation in 2014 and 19.1% in 2010, and 18.4% to 25.4% of total opioid use when accounting for OTC preparations. Between 2010 and 2014, 5.6% to 5.3% of buprenorphine, 8.1% to 6.3% fentanyl, 17.7% to 10.7% oxycodone, 18.4% to 11.0% tramadol, 38.4% to 21.0% hydromorphone, and 28.6% to 21.0% of prescription-only codeine utilisation were not accounted for in PBS/RPBS claims. CONCLUSIONS: Despite increased capture of less expensive (under co-payment) opioid items since 2012, PBS/RPBS claims still under-estimate opioid use in Australia, with varying degrees across opioids. The estimates generated in this study allow us to better understand the degree of under-estimation and account for these in research using Australia's national pharmaceutical claims data.

Prescription Opioid Access Patterns and Factors Associated with Increasing Number of Prescribers, Pharmacies, and Dispensings: An Observational Study Using Pharmaceutical Claims.

Objective: To examine associations between patient factors and increasing opioid access measured by three metrics: number of unique prescribers, pharmacies, and dispensings in 12 months. Methods: We used pharmaceutical claims for a random 10% sample of Australians age 18 years or older initiating or reinitiating strong opioid treatment (≥90 days of no strong opioid dispensing) between July 2010 and December 2012. We report the distribution of opioid access by metric. We used three separate zero-truncated negative binomial regressions to explore associations. We censored individuals 365 days after index date or at death, whichever occurred first. Results: Approximately 69,088 persons initiated or reinitiated strong opioid treatment; they were predominantly female (59.7%) with a median age of 71 years (interquartile range [IQR] = 58-81). Over one year, persons visited a median of two prescribers (IQR = 1-3), visited one dispensing pharmacy (IQR = 1-2), and had four opioid dispensings (IQR = 2-10). Three percent of people were in the top decile of opioid access distribution for all three metrics (four or more prescribers, three or more dispensing pharmacies, and 20 or more dispensings). Increasing opioid access was strongly associated with male sex, history of pain treatment (3 to 12 months prior to index date), malignancy treatment, or treatment for three or more other medical conditions. Conclusions: Delineating legitimate from extramedical opioid use based on pharmaceutical claims is imprecise. We demonstrated that "high" levels of access, defined in previous research, may reflect routine care for complex patients. Pharmaceutical claims have utility in examining population norms of prescription drug use and access patterns, and flagging persons at the extreme end of access, for at least one measure, who may warrant further investigation.

Defined daily doses (DDD) do not accurately reflect opioid doses used in contemporary chronic pain treatment.

OBJECTIVE: To assess how well the defined daily dose (DDD) metric reflects opioid utilisation among chronic non-cancer pain patients. DESIGN: Descriptive, cross-sectional study, utilising a 7-day medication diary. SETTING: Community-based treatment settings, Australia. SUBJECTS: A sample of 1101 people prescribed opioids for chronic non-cancer pain. METHODS: Opioid dose data was collected via a self-completed 7-day medication diary capturing names, strengths and doses of each medication taken in the past week. Median daily dose was calculated for each opioid. Comparisons were made to the World Health Organization's (WHO) DDD metric. RESULTS: WHO DDDs ranged from 0.6 to 7.1 times the median opioid doses used by the sample. For transdermal fentanyl and oral hydromorphone, the median dose was comparable with the DDD. The DDD for methadone was 0.6 times lower than the median doses used by this sample of chronic pain patients. In contrast, the DDD for oxycodone and transdermal buprenorphine, the most commonly used strong opioids for chronic pain in Australia, was two to seven times higher than actual doses used. CONCLUSIONS: For many opioids, there are key differences between the actual doses used in clinical practice and the WHO's DDDs. The interpretation of opioid utilisation studies using population-level DDDs may be limited, and a recalibration of the DDD for many opioids or the reporting of opioid utilisation in oral morphine equivalent doses is recommended. Copyright © 2017 John Wiley & Sons, Ltd.

Initiation of strong prescription opioids in Australia: cohort characteristics and factors associated with the type of opioid initiated.

AIMS: To describe the characteristics of Australians initiating strong opioids and examine the factors associated with the type of opioid initiated. METHODS: Pharmaceutical Benefits Scheme dispensing records were extracted for a 10% sample of people who initiated a strong opioid treatment episode (buprenorphine, fentanyl, hydromorphone, morphine, oxycodone) between 29 September 2009 and 31 December 2013, as evidenced by the absence of a strong opioid dispensing for at least 90 days. The cohort was restricted to people with complete medicines ascertainment. Socio-demographic characteristics, previous dispensing histories and index opioid use were examined. Multinomial logistic regression was used to calculate adjusted relative risk ratios (aRRRs) and 95% confidence intervals (CIs) to determine the factors associated with the type of opioid medicine initiated, relative to oxycodone. RESULTS: The cohort consisted of 125 335 people: 58.3% were female and 63.7% were aged ≥65 years. The most commonly initiated strong opioid was oxycodone (72.8%), usually 5 mg immediate-release tablets (76.1%). Compared to people aged 18-44 years, those ≥85 years were 14.18 times as likely (95% CI 12.67-15.87) to initiate morphine than oxycodone. Compared to people without a cancer treatment history, those with a cancer treatment history were 2.34 times as likely (95% CI 2.11-2.60) to initiate morphine than oxycodone. CONCLUSIONS: The most commonly initiated strong opioid was oxycodone, usually at lower strengths. Those who initiated oxycodone were more likely to be younger with no previous cancer treatment history. As these are high-risk characteristics for potential harms, a judicious approach when initiating strong opioids for this group is necessary.

An ecological study of the extent and factors associated with the use of prescription and over-the-counter codeine in Australia.

PURPOSE: The extent and factors associated with codeine use in the community remain poorly understood despite the widespread global use of codeine. The aim of this study was to examine the use of prescription and over-the-counter (OTC) codeine in Australia and identify the geographic and socio-demographic characteristics associated with prescription and OTC codeine use. METHODS: National sales data for prescription and OTC codeine (supplied by IMS Health) were used to estimate codeine utilisation (in pack sales and milligrammes) in Australia during 2013, mapped to Australian Bureau of Statistics (ABS) Statistical Local Areas (SLAs) and Remoteness Areas. Socio-demographic characteristics and total population estimates of SLAs were obtained from the ABS. SLA-level data on sex, age distribution, income, occupations involving physical labour and number of pharmacies were included in linear regression analyses to examine their association with total, prescription and OTC codeine use. RESULTS: In total, 27,780,234 packs of codeine were sold in Australia during 2013, equating to 12,376 kg. OTC codeine preparations accounted for 15,490,207 packs (55.8 %) or 4967.30 kg (40.1 %). Nationally, an estimated 1.24 packs (or 554.10 mg) of codeine were sold per person; utilisation was higher in more remote areas. SLAs with a higher percentage of low-income earning households had the highest rates of prescription codeine use (ß 0.16, p < 0.001), whereas SLAs with a higher percentage of males had the highest rates of OTC codeine use (ß 0.22, p < 0.001). CONCLUSIONS: Codeine use is common in Australia, with clear distinctions in the geographic and socio-demographic characteristics associated with prescription and OTC codeine use.

A synthesis of oral morphine equivalents (OME) for opioid utilisation studies.

PURPOSE: Oral Morphine Equivalent (OME) doses are increasingly being used as a metric to represent opioid use. Driven by a growing need from pharmacoepidemiological studies, the objective of this study was to develop a comprehensive OME conversion table that can be used by researchers to calculate OMEs in a consistent and systematic way. METHODS: Clinical guidelines and literature sources were collated and synthesised to develop recommended OME conversion factors that can be used for research studies on opioids (including different formulations and routes of administration) currently available internationally including Australia, the United Kingdom, Europe, the United States and Canada. RESULTS: No single resource includes all opioids that are currently available. Although there was some variation in conversion factors reported in different sources, overall, suggested conversion factors were mostly consistent across national and international sources. CONCLUSIONS: The use of the OME metric appears optimal for opioid utilisation studies as it facilities both interpretation and comparison between opioids and geographical locations. We have presented a synthesis of published OME conversion factors that can be applied to pharmacoepidemiological studies of opioids, in addition to a discussion of the considerations and caveats in using OME as a metric for opioid use. Copyright © 2015 John Wiley & Sons, Ltd.