Prevalence and incidence of prescription opioid analgesic use in Australia

Abstract

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.

Transition to high‐dose or strong opioids: a population‐based study of people initiating opioids in Australia

“…Our results have clinical practice and policy implications because high doses have been associated with substantial morbidity and mortality, including, falls, fractures, hospitalization, motor vehicle accidents, opioid‐related overdose and death . A recent Australian study reported that 1.9 million people initiate opioids each year . By extrapolation, approximately 26 600 people who initiate opioids escalate to high doses over 12 months.…”

“…Previous Australian research has indicated that the RxRisk‐V tool identifies fewer people with cancer compared to the Charlson's Comorbidity Index (43.2 versus 67.2%), which is widely used and considered a ‘gold standard’ approach to assess disease burden . For this reason we used a more comprehensive medication‐based indicator of cancer treatment that included other anti‐neoplastic therapies such as hormonal cancer therapies . Cancer treatment history was used as a predictor because cancer‐related pain could influence the rate of opioid transitions.…”

“…Increases in overdose deaths have been linked to increases in opioid use for chronic non‐cancer pain (CNCP) . Although the prevalence of opioid use has stabilized in North America and Australia since 2012 , there is ongoing concern about high‐dose opioid use . The average daily dose in the United States declined from 58 mg oral morphine equivalents (OMEs)/day in 2010 to 48 mg OMEs/day in 2015, but the dispensed OMEs per person remained six times higher in the highest‐prescribing than in the lowest‐prescribing counties .…”

“…Prescribing of high‐dose opioids (> 200 mg OMEs/day) doubled from 4.2% in 2003 to 8.7% in 2014 in Ontario, Canada . The incidence of opioid use slightly declined from 2013 to 2017 in Australia, but initiation of strong opioids increased during this period . Of the 1.9 million adults who initiate opioids each year in Australia , nearly 50 000 will become persistent users .…”

“…The incidence of opioid use slightly declined from 2013 to 2017 in Australia, but initiation of strong opioids increased during this period . Of the 1.9 million adults who initiate opioids each year in Australia , nearly 50 000 will become persistent users . It is unclear how many of these people escalate to high doses or transition to strong opioids.…”