Medicine utilization studies in Australian individual-level dispensing data: A blinded, multi-center replicated analysis.

PURPOSE: Medicine dispensing data require extensive preparation when used for research and decisions during this process may lead to results that do not replicate between independent studies. We conducted an experiment to examine the impact of these decisions on results of a study measuring discontinuation, intensification, and switching in a cohort of patients initiating metformin. METHODS: Four Australian sites independently developed a HARmonized Protocol template to Enhance Reproducibility (HARPER) protocol and executed their analyses using the Australian Pharmaceutical Benefits Scheme 10% sample dataset. Each site calculated cohort size and demographics and measured treatment events including discontinuation, switch to another diabetes medicine, and intensification (addition of another diabetes medicine). Time to event and hazard ratios for associations between cohort characteristics and each event were also calculated. Concordance was assessed by measuring deviations from the calculated median of each value across the sites. RESULTS: Good agreement was found across sites for the number of initiators (median: 53 127, range: 51 848-55 273), gender (56.9% female, range: 56.8%-57.1%) and age group. Each site employed different methods for estimating days supply and used different operational definitions for the treatment events. Consequently, poor agreement was found for incidence of discontinuation (median 55%, range: 34%-67%), switching (median 3.5%, range: 1%-7%), intensification (median 8%, range: 5%-12%), time to event estimates and hazard ratios. CONCLUSIONS: Differences in analytical decisions when deriving exposure from dispensing data affect replicability. Detailed analytical protocols, such as HARPER, are critical for transparency of operational definitions and interpretations of key study parameters.

Prescription retinoid and contraception use in women in Australia: A population-based study.

BACKGROUND/OBECTIVES: Oral retinoids are teratogenic, and pregnancy avoidance is an important part of retinoid prescribing. Australia does not have a standardised pregnancy prevention programme for women using oral retinoids, and the contraception strategies for women who use oral retinoids are not well understood. The objectives were to determine trends in the use of prescription retinoids among Australian reproductive-aged women and whether women dispensed oral retinoids used contraception concomitantly. METHODS: This was a population-based study using Australian Pharmaceutical Benefits (PBS) dispensing claims for a random 10% sample of 15-44-year-old Australian women, 2013 - 2021. We described rates and annual trends in dispensing claims for PBS-listed retinoids and contraceptives. We also estimated concomitant oral retinoid and contraceptive use on the day of each retinoid dispensing and determined if there was a period of contraceptive treatment that overlapped. Estimates were then extrapolated to the national level. RESULTS: There were 1,545,800 retinoid dispensings to reproductive-aged women; 57.1% were oral retinoids. The rate of retinoid dispensing to reproductive-aged women increased annually, from 28 dispensings per 1000 population in 2013 to 41 per 1000 in 2021. The rate of oral retinoid dispensing doubled over the study period, from 14 dispensings per 1000 population in 2013 to 28 per 1000 in 2021, while topical retinoid dispensing did not change. Only 25% of oral retinoid dispensings had evidence of concomitant contraceptive use in 2021. CONCLUSIONS: Rates of oral retinoid dispensing have doubled among reproductive-aged women over the past decade. A large percentage of oral retinoid use does not appear to have concomitant contraception use, posing a risk of teratogenic effects in pregnancies.

Prescribed medicine use and extent of off-label use according to age in a nationwide sample of Australian children.

BACKGROUND: Medicine prescribing for children is impacted by a lack of paediatric-specific dosing, efficacy and safety data for many medicines. OBJECTIVES: To estimate the prevalence of medicine use among children and the rate of 'off-label' prescribing according to age at dispensing. METHODS: We used population-wide primarily outpatient dispensing claims data for 15% of Australian children (0-17 years), 2013-2017 (n = 840,190). We estimated prescribed medicine use and 'off-label' medicine use according to the child's age (<1 year, 1-5 years, 6-11 years, 12-17 years) defined as medicines without age-appropriate dose recommendations in regulator-approved product information. Within off-label medicines, we also identified medicines with and without age-specific dose recommendations in a national prescribing guide, the Australian Medicines Handbook Children's Dosing Companion (AMH CDC). RESULTS: The overall dispensing rate was 2.0 dispensings per child per year. The medicines with the highest average yearly prevalence were systemic antibiotics (435.3 per 1000 children), greatest in children 1-5 years (546.9 per 1000). Other common medicine classes were systemic corticosteroids (92.7 per 1000), respiratory medicines (91.2 per 1000), acid-suppressing medicines in children <1 year (47.2 per 1000), antidepressants in children 12-17 years (40.3 per 1000) and psychostimulants in children 6-11 years (27.0 per 1000). We identified 12.2% of dispensings as off-label based on age, but 66.3% of these had age-specific dosing recommendations in the AMH CDC. Among children <1 year, off-label dispensings were commonly acid-suppressing medicines (35.5%) and topical hydrocortisone (33.1%); in children 6-11 years, off-label prescribing of clonidine (16.0%) and risperidone (13.1%) was common. Off-label dispensings were more likely to be prescribed by a specialist (21.7%) than on-label dispensings (7.5%). CONCLUSIONS: Prescribed medicine use is common in children, with off-label dispensings for medicines without paediatric-specific dosing guidelines concentrated in classes such as acid-suppressing medicines and psychotropics. Our findings highlight a need for better evidence to support best-practice prescribing.

Patterns of opioid use in older people diagnosed with cancer in New South Wales, Australia.

PURPOSE: Opioids provide effective analgesia for most cancer patients, but little is known about individual-level opioid use after cancer diagnosis. We examined the patterns of and factors associated with opioid use in older people diagnosed with cancer. METHODS: We used the Department of Veterans' Affairs (DVA) client data linked with the New South Wales (NSW) Cancer Registry and the Repatriation Pharmaceutical Benefits Scheme data. We included people aged ≥65 years diagnosed with cancer in NSW, Australia in 2005 to 2015. We examined patterns of opioid use in the 12 months after cancer diagnosis and used cause-specific hazards models to examine factors associated with opioid use. RESULTS: Of 13 527 people diagnosed with cancer, 51% were dispensed opioids after their diagnosis. We observed the highest proportions of use in people diagnosed with pancreas, liver, or lung cancers. Opioid use was associated with female sex, younger age, more advanced degree of cancer spread, opioid use before cancer diagnosis, and multimorbidity. Forty-four percentages of all people dispensed opioids had a history of opioid use in the 12 months before their cancer diagnosis; these people had higher median number of different opioids and opioid dispensings, and a shorter time to first opioid dispensing than opioid-naive people. CONCLUSION: Our study suggests that many older cancer patients were dispensed opioids before their cancer diagnosis. Previously opioid-treated people had more intense opioid use patterns after diagnosis than opioid-naïve people. Acknowledging the history of opioid use is important as it may complicate pain treatment in clinical practice.

Anticholinergic medicines use among older adults before and after initiating dementia medicines.

AIMS: We investigated anticholinergic medicines use among older adults initiating dementia medicines. METHODS: We used Pharmaceutical Benefits Scheme dispensing claims to identify patients who initiated donepezil, rivastigmine, galantamine or memantine between 1 January 2013 and 30 June 2017 (after a period of ≥180 days with no dispensing of these medicines) and remained on therapy for ≥180 days (n = 4393), and dispensed anticholinergic medicines in the 180 days before and after initiating dementia medicines. We further examined anticholinergic medicines prescribed by a prescriber other than the one initiating dementia medicines. RESULTS: One-third of the study cohort (1439/4393) was exposed to anticholinergic medicines up to 180 days before or after initiating dementia medicines. Among patients exposed to anticholinergic medicines, 46% (659/1439) had the same medicine dispensed before and after initiating dementia medicines. The proportion of patients dispensed anticholinergic medicines increased by 2.5% (95% confidence interval [CI]: 1.3-3.7) after initiating dementia medicines. Antipsychotics use increased by 10.1% (95% CI: 7.6-12.7) after initiating dementia medicines; driven by increased risperidone use (7.3%, 95% CI: 5.3-9.3). Nearly half of patients dispensed anticholinergic medicines in the 180 days after (537/1133), were prescribed anticholinergic medicines by a prescriber other than the one initiating dementia medicines. CONCLUSION: Use of anticholinergic medicines is common among patients initiating dementia medicines and this occurs against a backdrop of widespread campaigns to reduce irrational medicine combinations in this vulnerable population. Decisions about deprescribing medicines with questionable benefit among patients with dementia may be complicated by conflicting recommendations in prescribing guidelines.

Polypharmacy among older Australians, 2006-2017: a population-based study.

OBJECTIVE: To estimate the prevalence of polypharmacy among Australians aged 70 years or more, 2006-2017. DESIGN, SETTING AND PARTICIPANTS: Analysis of a random 10% sample of Pharmaceutical Benefits Scheme (PBS) data for people aged 70 or more who were dispensed PBS-listed medicines between 1 January 2006 and 31 December 2017. MAIN OUTCOME MEASURES: Prevalence of continuous polypharmacy (five or more unique medicines dispensed during both 1 April - 30 June and 1 October - 31 December in a calendar year) among older Australians, and the estimated number of people affected in 2017; changes in prevalence of continuous polypharmacy among older concessional beneficiaries, 2006-2017. RESULTS: In 2017, 36.1% of older Australians were affected by continuous polypharmacy, or an estimated 935 240 people. Rates of polypharmacy were higher among women than men (36.6% v 35.4%) and were highest among those aged 80-84 years (43.9%) or 85-89 years (46.0%). The prevalence of polypharmacy among PBS concessional beneficiaries aged 70 or more increased by 9% during 2006-2017 (from 33.2% to 36.2%), but the number of people affected increased by 52% (from 543 950 to 828 950). CONCLUSIONS: The prevalence of polypharmacy among older Australians is relatively high, affecting almost one million older people, and the number is increasing as the population ages. Our estimates are probably low, as we could not take over-the-counter or complementary medicines or private prescriptions into account. Polypharmacy can be appropriate, but there is substantial evidence for its potential harm and the importance of rationalising unnecessary medicines, particularly in older people.

Anticipating the effects of restricting high-dose preparations of strong opioids in Australia: A population-based analysis to inform the current policy debate.

PURPOSE: Countries worldwide are developing a variety of strategies to combat the opioid epidemic, such as restricting access to high-strength opioid formulations. We aimed to examine the dispensing patterns of strong opioids by dose units (DUs), age, and sex. METHODS: We used Australian population-level dispensing data from January 2003 to December 2015 and categorised strong opioids by DU: very low, low, moderate, and high, corresponding to total daily doses of less than or equal to 25, 26 to 50, 51 to 100, and greater than 100 morphine milligramme equivalents, respectively. We measured trends in strong opioid use as dispensings/1000 population/year and stratified dispensing in 2015 by patient age and sex. RESULTS: From 2003 to 2015, strong opioid dispensing of very low, low, moderate, and high DU increased 6.7-, 6.2-, 2.2-, and 1.8-fold, respectively. The increase in very low and low DU dispensing was driven primarily by oxycodone (5, 10, and 15 mg tablets and capsules) and buprenorphine transdermal patches. In 2015, the number of dispensings/1000 population for very low, low, moderate, and high DU were 180.3, 77.0, 52.7, and 34.8, respectively. Females aged greater than or equal to 85 years had the highest opioid use, ranging from 157.1 dispensings/1000 population for high DU to 2104.5 dispensings/1000 population for very low DU. In contrast, the high DU dispensings in males aged 25 to 64 years exceeded their female counterparts by approximately 1.3-fold. CONCLUSION: Relative to moderate and high DU strong opioids, dispensing of very low and low DU strong opioids increased dramatically during the study period in Australia. Future studies investigating opioids use and harms in elderly females and males between 25 to 64 years are warranted.

Trends in opioid utilisation in Australia, 2006-2015: Insights from multiple metrics.

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.

The relationship between solar UV exposure, serum vitamin D levels and serum prostate-specific antigen levels, in men from New South Wales, Australia: the CHAMP study.

PURPOSE: We aim to determine the relationship between season, personal solar UV exposure, serum 25(OH)D and 1,25(OH)2D and serum prostate-specific antigen (PSA) levels. METHODS: Questionnaire data and blood samples were collected at baseline from participants of the Concord Health and Ageing in Men Project (n = 1,705), aged 70 and above. They were grouped as men 'free of prostate disease' for those with no record of having prostate cancer, benign prostatic hyperplasia, or prostatitis and with serum PSA levels below 20 ng/mL, and 'with prostate disease' for those with a record of either of these diseases or with serum PSA levels 20 ng/mL or above. Personal solar UV exposure (sUV) was estimated from recalled hours of outdoor exposure and weighted against ambient solar UV radiation. Sera were analysed to determine levels of PSA, 25(OH)D and 1,25(OH)2D, and analysed using multiple regression, adjusting for age, BMI and region of birth. RESULTS: The association between sUV and serum PSA levels was conditional upon season (p interaction = 0.04). There was no direct association between serum PSA and 25(OH)D in both groups of men. There was a positive association between serum PSA and 1,25(OH)2D in men with prostate disease (mean = 110.6 pmol/L; p heterogeneity = 0.03), but there was no such association in men free of prostate disease (mean = 109.3 pmol/L; p heterogeneity = 0.8). CONCLUSION: The association between PSA and sUV may only be evident at low solar UV irradiance, and this effect may be independent of serum vitamin D levels.

Prostate-specific antigen levels in men aged 70 years and over: findings from the CHAMP study.

OBJECTIVE: To describe values of serum prostate-specific antigen (PSA) in older men without diagnosed prostate cancer, categorised by age and country of birth, and to describe self-reported prostate cancer screening. DESIGN, PARTICIPANTS AND SETTING: A cohort study (the Concord Health and Ageing in Men Project) involving a representative sample of 1434 eligible community-dwelling men with no diagnosis of prostate cancer who were aged 70 years and over and living in a defined geographic area in Sydney, with baseline data collected between 28 January 2005 and 4 June 2007. MAIN OUTCOME MEASURES: Serum PSA levels and self-reported prostate cancer screening. RESULTS: 11% of men (155) had a PSA level of ≥6.5 ng/mL, increasing from 7.5% of men aged 70-74 years to 31.4% of men aged≥90 years. PSA levels varied with ethnicity, with Australian-born men (695) having the highest levels (median, 2.3 ng/mL; 5th-95th percentile, 0.4-10.1 ng/mL), followed by men born in China (n=42; 2.1 ng/mL; 0.4-12.4 ng/mL), United Kingdom and Ireland (n=70; 1.9 ng/mL; 0.3-8.9 ng/mL), Greece (n=59; 1.5 ng/mL; 0.2-6.1 ng/mL), and Italy (n=293; 1.4 ng/mL; 0.3-7.2 ng/mL). A PSA test in the previous 2 years was reported by 48% of participants, and a digital rectal examination (DRE) in the previous 2 years by 37%. CONCLUSIONS: A significant number of men aged over 70 years reported recent prostate cancer tests. The PSA level ranges reported in this cohort will help with interpreting serum PSA level findings in men aged over 70 years.

Trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia (2003-2015).

INTRODUCTION: Fentanyl-related overdose is an ongoing concern among countries with high prescription opioid utilisation. This study examines trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia between 2003 and 2015, overall, and by age/sex. METHODS: This was a retrospective nationwide study of prescription dispensings and coronial records. Transdermal fentanyl utilisation was examined using Pharmaceutical Benefits Scheme dispensing records. Details of fatal fentanyl overdoses were extracted from the National Coronial Information System. RESULTS: Transdermal fentanyl utilisation increased 5.1-fold between 2003 and 2015, from 0.28 to 1.39 mg/1000 population/day and was consistently higher among females and adults aged ≥85 years. The utilisation of higher strength patches (75 and 100 mcg/h) was more common among males aged 25-44 years. A total of 291 fatal fentanyl overdoses were recorded, increasing from no recorded deaths in 2003 to 2.23 deaths/1 000 000 population in 2015. Rates were higher among males (increasing from 0 to 3.72 deaths/1 000 000 population) and for adults aged 25-44 years (increasing from 0 to 5.34 deaths/1 000 000 population). The number of deaths/kg fentanyl dispensed was highest among males aged <25 years (45.45, 95% confidence interval 21.80-83.59). Most deaths (70.1%) involved the intravenous administration of fentanyl from transdermal patches. DISCUSSION AND CONCLUSIONS: Rates of transdermal fentanyl utilisation and fatal fentanyl overdose across Australia increased between 2003 and 2015. Although transdermal fentanyl utilisation was consistently greater among females and older adults, rates of fatal fentanyl overdose were highest among younger males. Interventions to reduce extramedical use among this high-risk population group are necessary to minimise fentanyl-related harms.

Trends in diabetes medication use in Australia, Canada, England, and Scotland: a repeated cross-sectional analysis in primary care.

BACKGROUND: Several new classes of glucose-lowering medications have been introduced in the past two decades. Some, such as sodium-glucose cotransporter 2 inhibitors (SGLT2s), have evidence of improved cardiovascular outcomes, while others, such as dipeptidyl peptidase-4 inhibitors (DPP4s), do not. It is therefore important to identify their uptake in order to find ways to support the use of more effective treatments. AIM: To analyse the uptake of these new classes among patients with type 2 diabetes. DESIGN AND SETTING: This was a retrospective repeated cross-sectional analysis in primary care. Rates of medication uptake in Australia, Canada, England, and Scotland were compared. METHOD: Primary care Electronic Medical Data on prescriptions (Canada, UK) and dispensing data (Australia) from 2012 to 2017 were used. Individuals aged ≥40 years on at least one glucose-lowering drug class in each year of interest were included, excluding those on insulin only. Proportions of patients in each nation, for each year, on each class of medication, and on combinations of classes were determined. RESULTS: Data from 238 619 patients were included in 2017. The proportion of patients on sulfonylureas (SUs) decreased in three out of four nations, while metformin decreased in Canada. Use of combinations of metformin and new drug classes increased in all nations, replacing combinations involving SUs. In 2017, more patients were on DPP4s (between 19.1% and 27.6%) than on SGLT2s (between 10.1% and 15.3%). CONCLUSION: New drugs are displacing SUs. However, despite evidence of better outcomes, the adoption of SGLT2s lagged behind DPP4s.

Adherence to Antiretroviral Regimens in Australia: A Nationwide Cohort Study.

The lifetime use of combination antiretroviral therapy (cART) highlights the need to understand patterns of and factors associated with adherence to cART. In this cohort study using a 10% random sample of dispensing claims data for eligible Australians, we identified 2042 people dispensed cART between January 2016 and December 2017 (mean age 48.0 ± 12.0 years old, 88.6% male, and 85.9% treatment experienced). We considered people to be adherent if the proportion of treatment coverage days was ≥80% in the 360 days after their first observed cART dispensing. We also used group-based trajectory modeling (GBTM) to examine different patterns of adherence for 360 days from first observed cART dispensing. Most commonly, people receiving cART were treated with two nucleoside/nucleotide reverse transcriptase inhibitors with an integrase strand transfer inhibitors (INSTI-46.6%). Overall, 1708 people [83.6% (95% confidential interval 82.0-85.3%)] remained adherent over 360 days. GBTM identified three distinct adherence patterns: nearly always adherent [67.8% (63.7-71.9%) of the cohort], moderate adherence [26.6% (23.0-30.1%)], and low adherence [5.6% (4.1-7.2%)]. People were more likely to belong to the "nearly always adherent" trajectory if they were older (per additional year of age), treated with an INSTI regimen, and on treatment for more than 6 months. Our study demonstrates that the 360-day adherence to cART is generally high, but approximately one-third maintain a moderate or low adherence pattern. The use of INSTI regimens and additional support of treatment adherence, especially among younger people and those initiating therapy, may further improve adherence.

Rapid and substantial increases in anticoagulant use and expenditure in Australia following the introduction of new types of oral anticoagulants.

OBJECTIVES: To quantify changes in anticoagulant use in Australia since the introduction of Non-vitamin K antagonist anticoagulants (NOACs) and to estimate government expenditure. DESIGN: Interrupted-time-series analysis quantifying anticoagulant dispensing, before and after first Pharmaceutical Benefits Scheme (PBS) NOAC listing in August 2009 for venous thromboembolism prevention; and expanded listing for stroke prevention in non-valvular atrial fibrillation (AF) in August 2013, up to June 2016. Estimated government expenditure on PBS-listed anticoagulants. SETTING AND PARTICIPANTS: PBS dispensing in 10% random sample of Australians, restricted to continuous concessional beneficiaries dispensed oral anticoagulants from July 2005 to June 2016. Total PBS anticoagulant expenditure was calculated using Medicare Australia statistics. MAIN OUTCOME MEASURES: Monthly dispensing and initiation of oral anticoagulants (warfarin, rivaroxaban, dabigatran or apixaban). Annual PBS anticoagulant expenditure. RESULTS: An estimated 149,180 concessional beneficiaries were dispensed anticoagulants (100% warfarin) during July 2005. This increased to 292,550 during June 2016, of whom 47.0%, 27.1%, 18.7% and 7.2% were dispensed warfarin, rivaroxaban, apixaban and dabigatran, respectively. Of 16,500 initiated on anticoagulants in June 2016, 24.3%, 38.2%, 30.0% and 7.5% were initiated on warfarin, rivaroxaban, apixaban, and dabigatran, respectively. Compared to July 2005-July 2013, from August 2013-June 2016, dispensings for all anticoagulants increased by 2,303 dispensings/month (p<0.001, 95%CI = [1,229 3,376]); warfarin dispensing decreased by 1,803 dispensings/month (p<0.001, 95%CI = [-2,606, -1,000]). Total PBS anticoagulant expenditure was $19.5 million (97.0% concessional) in 2008/09, of which 100% was warfarin and $203.3 million (86.2% concessional) in 2015/16, of which 11.2% was warfarin. CONCLUSIONS: The introduction of the NOACs led to substantial increases in anticoagulant use and expenditure in Australia.

International trends in antipsychotic use: A study in 16 countries, 2005-2014.

The objective of this study was to assess international trends in antipsychotic use, using a standardised methodology. A repeated cross-sectional design was applied to data extracts from the years 2005 to 2014 from 16 countries worldwide. During the study period, the overall prevalence of antipsychotic use increased in 10 of the 16 studied countries. In 2014, the overall prevalence of antipsychotic use was highest in Taiwan (78.2/1000 persons), and lowest in Colombia (3.2/1000). In children and adolescents (0-19 years), antipsychotic use ranged from 0.5/1000 (Lithuania) to 30.8/1000 (Taiwan). In adults (20-64 years), the range was 2.8/1000 (Colombia) to 78.9/1000 (publicly insured US population), and in older adults (65+ years), antipsychotic use ranged from 19.0/1000 (Colombia) to 149.0/1000 (Taiwan). Atypical antipsychotic use increased in all populations (range of atypical/typical ratio: 0.7 (Taiwan) to 6.1 (New Zealand, Australia)). Quetiapine, risperidone, and olanzapine were most frequently prescribed. Prevalence and patterns of antipsychotic use varied markedly between countries. In the majority of populations, antipsychotic utilisation and especially the use of atypical antipsychotics increased over time. The high rates of antipsychotic prescriptions in older adults and in youths in some countries merit further investigation and systematic pharmacoepidemiologic monitoring.

The Australian Pharmaceutical Benefits Scheme data collection: a practical guide for researchers.

BACKGROUND: The Pharmaceutical Benefits Scheme (PBS) is Australia's national drug subsidy program. This paper provides a practical guide to researchers using PBS data to examine prescribed medicine use. FINDINGS: Excerpts of the PBS data collection are available in a variety of formats. We describe the core components of four publicly available extracts (the Australian Statistics on Medicines, PBS statistics online, section 85 extract, under co-payment extract). We also detail common analytical challenges and key issues regarding the interpretation of utilisation using the PBS collection and its various extracts. CONCLUSIONS: Research using routinely collected data is increasing internationally. PBS data are a valuable resource for Australian pharmacoepidemiological and pharmaceutical policy research. A detailed knowledge of the PBS, the nuances of data capture, and the extracts available for research purposes are necessary to ensure robust methodology, interpretation, and translation of study findings into policy and practice.

Ambient UV, personal sun exposure and risk of multiple primary melanomas.

OBJECTIVE: Sun exposure is the main cause of melanoma in populations of European origin. No previous study has examined the effect of sun exposure on risk of multiple primary melanomas compared with people who have one melanoma. METHODS: We identified and enrolled 2,023 people with a first primary melanoma (controls) and 1,125 with multiple primary melanomas (cases) in seven centers in four countries, recorded their residential history to assign ambient UV and interviewed them about their sun exposure. RESULTS: Risk of multiple primary melanomas increased significantly (P<0.05) to OR=2.10 for the highest exposure quarter of ambient UV irradiance at birth and 10 years of age, to OR=1.38 for lifetime recreational sun exposure, to OR=1.85 for beach and waterside activities, to OR=1.57 for vacations in a sunnier climate, to OR=1.50 for sunburns. Occupational sun exposure did not increase risk (OR=1.03 for highest exposure). Recreational exposure at any age increased risk and appeared to add to risk from ambient UV in early life. CONCLUSIONS: People who have had a melanoma can expect to reduce their risk of a further melanoma by reducing recreational sun exposure whatever their age. The same is probably true for a person who has never had a melanoma.