Melbourne School of Population and Global Health - Research Publications
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ItemTrends in opioid utilisation in Australia, 2006-2015: Insights from multiple metrics(WILEY, 2018-05)PURPOSE: Population-based observational studies have documented global increases in opioid analgesic use. Many studies have used a single population-adjusted metric (number of dispensings, defined daily doses [DDDs], or oral morphine equivalents [OMEs]). We combine these volume-based metrics with a measure of the number of persons dispensed opioids to gain insights into Australian trends in prescribed opioid use. METHODS: We obtained records of prescribed opioid dispensings (2006-2015) subsidised under Australia's Pharmaceutical Benefits Scheme. We used dispensing claims to quantify annual changes in use according to 3 volume-based metrics: DDD/1000 pop/day, OME/1000 pop/day, and dispensings/1000 pop. We estimated the number of persons dispensed at least one opioid in a given year (persons)/1000 pop using data from a 10% random sample of Pharmaceutical Benefits Scheme-eligible Australians. RESULTS: Total opioid use increased according to all metrics, especially OME/1000 pop/day (51% increase) and dispensings/1000 pop (44%). Weaker opioid use remained stable or declined; strong opioid use increased. The rate of persons accessing weaker opioids only decreased 31%, and there was a 238% increase in persons dispensed only strong opioids. Strong opioid use also increased according to dispensings/1000 pop (140%), OME/1000 pop/day (80%), and DDD/1000 pop/day (71% increase). CONCLUSIONS: Our results suggest that the increases in total opioid use between 2006 and 2015 were predominantly driven by a growing number of people treated with strong opioids at lower medicine strengths/doses. This method can be used with or without person-level data to provide insights into factors driving changes in medicine use over time.
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ItemTo what extent do data from pharmaceutical claims underestimate opioid analgesic utilisation in Australia?(WILEY, 2018-05)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.
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ItemPharmaceutical opioid use and harm in Australia: The need for proactive and preventative responses(WILEY, 2018-04)There are parallels between the North American experience of escalating pharmaceutical opioid utilisation and harm and the trends being observed in Australia. In Australia, opioid utilisation has increased dramatically over the past two decades. There have been significant shifts away from the predominant prescribing of 'weak' and short-acting opioids, to 'strong' and long-acting opioids, for an increasing range of chronic pain indications. In concordance with escalating use, Australia is experiencing increases in opioid-related hospital admissions and overdose, as well as opioid dependence and treatment seeking. Despite increasing concern regarding pharmaceutical opioid use and harms in Australia, responses have been limited. There have been no recent changes in regulatory systems for prescription-only pharmaceutical opioids, opioid prescribing guidelines, limits on doctors' prescribing, monitoring of patient or doctor access to opioids, or in access to medicines via public subsidy. Potentially abuse-deterrent opioid formulations have entered the Australian market, with studies suggesting that these formulations are less likely to be tampered with by people who inject drugs; but to date, there have been limited impacts on opioid utilisation and harm. Additional strategies may include enhancing access to effective approaches to pain management and opioid dependence, and scaling-up naloxone provision. There is a unique opportunity for a proactive and preventative response to pharmaceutical opioids in Australia, to avoid experiencing the scale of problems seen elsewhere.
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ItemThe association between psychotic experiences and disability: results from the WHO World Mental Health Surveys(WILEY, 2017-07)OBJECTIVE: While psychotic experiences (PEs) are known to be associated with a range of mental and general medical disorders, little is known about the association between PEs and measures of disability. We aimed to investigate this question using the World Mental Health surveys. METHOD: Lifetime occurrences of six types of PEs were assessed along with 21 mental disorders and 14 general medical conditions. Disability was assessed with a modified version of the WHO Disability Assessment Schedule. Descriptive statistics and logistic regression models were used to investigate the association between PEs and high disability scores (top quartile) with various adjustments. RESULTS: Respondents with PEs were more likely to have top quartile scores on global disability than respondents without PEs (19.1% vs. 7.5%; χ2 = 190.1, P < 0.001) as well as greater likelihood of cognitive, social, and role impairment. Relationships persisted in each adjusted model. A significant dose-response relationship was also found for the PE type measures with most of these outcomes. CONCLUSIONS: Psychotic experiences are associated with disability measures with a dose-response relationship. These results are consistent with the view that PEs are associated with disability regardless of the presence of comorbid mental or general medical disorders.
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ItemHealth service utilisation attributable to methamphetamine use in Australia: Patterns, predictors and national impact(WILEY, 2018-02)AIM AND BACKGROUND: We estimated health service utilisation attributable to methamphetamine use, its national impact and examined other predictors of health service utilisation among dependent methamphetamine users. METHOD: Past year rates of health service utilisation (number of attendances for general hospitals, psychiatric hospitals, emergency departments, general practitioners, psychiatrists, counsellors or psychologists, and dentists) were estimated for three levels of methamphetamine use (no use, < weekly, ≥ weekly) using panel data from a longitudinal cohort of 484 dependent methamphetamine users from Sydney and Brisbane, Australia. Marginal rates for methamphetamine use were multiplied by 2013 prevalence estimates from the National Drug Strategy Household Survey. Covariates included other substance use, demographics, mental disorders and drug treatment. FINDINGS: Health service use was high. More frequent methamphetamine use was associated with more frequent presentations to emergency departments (incidence rate ratios 1.3-2.1) and psychiatric hospitals (incidence rate ratios 5.3-8.3) and fewer presentations to general practitioners, dentists and counsellors. We estimate methamphetamine use accounted for between 28 400 and 80 900 additional psychiatric hospital admissions and 29 700 and 151 800 additional emergency department presentations in 2013. More frequent presentations to these services were also associated with alcohol and opioid use, comorbid mental health disorders, unemployment, unstable housing, attending drug treatment, low income and lower education. CONCLUSIONS: Frequent methamphetamine use has a significant impact on emergency medical and psychiatric services. Better provision of non-acute health care services to address the multiple health and social needs of dependent methamphetamine users may reduce the burden on these acute care services. [McKetin R, Degenhardt L, Shanahan M, Baker AL, Lee NK, Lubman DI. Health service utilisation attributable to methamphetamine use in Australia: patterns, predictors and national impact. Drug Alcohol Rev 2017;00:000-000].
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ItemA Cross-National Examination of Differences in Classification of Lifetime Alcohol Use Disorder Between DSM-IV and DSM-5: Findings from the World Mental Health Survey(WILEY, 2016-08)BACKGROUND: The current study sought to examine the diagnostic overlap in DSM-IV and DSM-5 alcohol use disorder (AUD) and determine the clinical correlates of changing diagnostic status across the 2 classification systems. METHODS: DSM-IV and DSM-5 definitions of AUD were compared using cross-national community survey data in 9 low-, middle-, and high-income countries. Participants were 31,367 respondents to surveys in the World Health Organization's World Mental Health Survey Initiative. The Composite International Diagnostic Interview, version 3.0, was used to derive DSM-IV and DSM-5 lifetime diagnoses of AUD. Clinical characteristics, also assessed in the surveys, included lifetime DSM-IV anxiety; mood and drug use disorders; lifetime suicidal ideation, plan, and attempt; general functional impairment; and psychological distress. RESULTS: Compared with DSM-IV AUD (12.3%, SE = 0.3%), the DSM-5 definition yielded slightly lower prevalence estimates (10.8%, SE = 0.2%). Almost one-third (n = 802) of all DSM-IV abuse cases switched to subthreshold according to DSM-5 and one-quarter (n = 467) of all DSM-IV diagnostic orphans switched to mild AUD according to DSM-5. New cases of DSM-5 AUD were largely similar to those who maintained their AUD across both classifications. Similarly, new DSM-5 noncases were similar to those who were subthreshold across both classifications. The exception to this was with regard to the prevalence of any lifetime drug use disorder. CONCLUSIONS: In this large cross-national community sample, the prevalence of DSM-5 lifetime AUD was only slightly lower than the prevalence of DSM-IV lifetime AUD. Nonetheless, there was considerable diagnostic switching, with a large number of people inconsistently identified across the 2 DSM classifications.
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ItemInitiation of strong prescription opioids in Australia: cohort characteristics and factors associated with the type of opioid initiated(WILEY, 2016-10)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.
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ItemCommunity pharmacist knowledge, attitudes and confidence regarding naloxone for overdose reversal(WILEY-BLACKWELL, 2016-12)AIM: Given the potential to expand naloxone supply through community pharmacy, the aim of this study was to estimate Australian pharmacists': (1) level of support for overdose prevention, (2) barriers and facilitators for naloxone supply and (3) knowledge about naloxone administration. DESIGN: Online survey from nationally representative sample of community pharmacies. SETTING: Australia, September-November 2015. PARTICIPANTS: A total of 1317 community pharmacists were invited to participate with 595 responses (45.1%). MEASUREMENTS: We assessed attitudes towards harm reduction, support for overdose prevention, attitudes and knowledge about naloxone. We tested the association between attitudes towards harm reduction and different aspects of naloxone supply. FINDINGS: Pharmacists were willing to receive training about naloxone (n = 479, 80.5%) and provide naloxone with a prescription (n = 537, 90.3%). Fewer (n = 234, 40.8%) were willing to supply naloxone over-the-counter. Positive attitudes towards harm reduction were associated with greater willingness to supply naloxone with a prescription [odds ratio (OR) = 1.15, 95% confidence interval (CI) = 1.11-1.19] and over-the-counter (OR = 1.13, 95% CI = 1.09-1.17). Few pharmacists were confident they could identify appropriate patients (n = 203, 34.1%) and educate them on overdose and naloxone use (n = 190, 31.9%). Mean naloxone knowledge scores were 1.8 (standard deviation 1.7) out of 5. More than half the sample identified lack of time, training, knowledge and reimbursement as potential barriers for naloxone provision. CONCLUSION: Community pharmacists in Australia appear to be willing to supply naloxone. Low levels of knowledge about naloxone pharmacology and administration highlight the importance of training pharmacists about overdose prevention.