Opioid overdose mortality continues to rise, but major shifts have occurred in the relative proportion of deaths attributed to specific opioid types. Opioids can be categorized into natural/semisynthetic opioids (e.g. including prescribed hydrocodone and oxycodone), heroin, synthetic opioids besides methadone (e.g. fentanyl, often illicit) and methadone. Overdoses in the prior decade were primarily due to natural/semisynthetic opioids from prescribed sources. Recently, overdoses from heroin and synthetic opioids, from illicit sources, have risen. Heroin overdoses increased by 33% per year from 2010-2014 and in 2015 and 2016 (latest data) exceeded deaths from natural/semisynthetic opioids.
Despite these dramatic changes in opioids involved in overdose, existing models of risk are based on data that predate shifts and fail to capture risk factors for heroin and synthetic opioid overdoses, which may differ from those associated with prescription opioid overdose. Per the CDC’s 2017 Annual Surveillance Report of Drug-Related Risks and Outcomes, examining recent data is needed “to address a diverse and evolving array of drug types.” In response to policies trying to reduce overdose risk, opioid prescribing has decreased substantially since 2012 and high dosage opioid prescribing (daily dosage ≥90 MME) in particular declined by 41.4% from 2010 to 2015. Yet, overdoses continue to rise. Given the uncertainty about why prescribing changes have not resulted in concurrent decreases in overdose rates, it is critical to understand the impacts of opioid reduction measures on overdose rates across the specific types of opioids involved.