Trends in opioid prescribing in Australia: a systematic review

Objective This review systematically identified studies that estimated the prevalence of prescription opioid use in Australia, assessed the prevalence estimates for bias and identified areas for future research. Methods Literature published after 2000 containing a potentially representative estimate of prescription opioid use in adults, in the community setting, in Australia was included in this review. Studies that solely assessed opioid replacement, illicit opioid usage or acute hospital in-patient use were excluded. Databases searched included PubMed, EMBASE, Web of Science and the grey literature. Results The search identified 2253 peer-reviewed publications, with 34 requiring full-text review. Of these, 20 were included in the final qualitative analysis, in addition to four publications from the grey literature. Most studies included analysed prescription claims data for medicines dispensed via Australia's national medicines subsidy scheme (the Pharmaceutical Benefits Scheme). Although data sources were good quality, all prevalence estimates were at least at moderate risk of bias, predominantly due to incompleteness of data or potential confounding. Included publications demonstrated a significant rise in opioid use up to 2017 (including a 15-fold increase in prescriptions dispensed over the 20 years to 2015), predominantly driven by a sharp rise in oxycodone use. Although opioid prescription numbers continue to escalate, usage, as measured by oral morphine equivalent per capita, may have plateaued since 2014. Codeine remains the most prevalently obtained opioid, followed by oxycodone and tramadol. There was a substantial delay (median 30 months; interquartile range 20-37 months) to publication of opioid usage data from time of availability. Conclusions Australia has experienced a marked increase in opioid prescribing since the 1990s. Current published literature is restricted to incomplete, delayed and historical data, limiting the ability of clinicians and policy makers to intervene appropriately. What is known about the topic? Opioid prescriptions in Australia have continued to increase since the 1990s and may be mirroring the epidemic being seen in the US. What does this paper add? This paper systematically identifies all publications that have examined the prevalence of prescription opioid use in Australia since 2000, and only identified prevalence estimates that were at moderate or high risk of bias, and found significant delays to publication of these estimates.