Prescription opioid use and non-fatal overdose in a cohort of injection drug users

Abstract

Background There is growing concern regarding rising rates of prescription drug-related deaths among the general North American population as well as increasing availability of illicitly obtained prescription opioids. Concurrently among people who inject drugs (IDU), illicit prescription opioid use has increased while non-fatal overdose remains a major source of morbidity. Objectives This study aimed to evaluate whether the use of POs was associated with non-fatal overdose among IDU in Vancouver, Canada. Methods Data was obtained from two open prospective cohorts of IDU between December 2005 and May 2013. We used generalized estimating equation (GEE) logistic regression to evaluate the association between prescription opioid use and non-fatal overdose, adjusting for various social, demographic, and behavioral factors. Results There were 1,614 IDU, including 541 (33.5%) women, who were recruited and included in this analysis. At baseline, 526 (32.6%) reported using POs and 118 (7.3%) reported experiencing an overdose in the previous six months. In a multivariable analysis, prescription opioid use remained independently associated with non-fatal overdose (adjusted odds ratio: 1.61, 95% confidence interval: 1.32–1.95), after adjusting for confounders. Conclusion We observed relatively high rates of prescription opioid use among IDU in this setting, and found an independent association between prescription opioid use and non-fatal overdose. Our data is likely representative of riskier substance use associated with those who use prescription opioids within our sample. Interventions to prevent and respond to overdoses should consider the higher risk profiles of IDU who use prescription opioids.

The effect of prescription opioid injection on the risk of non-fatal overdose among people who inject drugs

“…A previous study among these two cohorts noted a significant and positive relationship between PO use (i.e., injection and non-injection administration) and non-fatal overdose (Lake et al, 2015). In the current study, which controlled for non-injection PO use, we were able to identify some underlying trends in this previously noted association; namely, those who are using POs via non-injection and those who are injecting POs in addition to heroin may have accounted for the bulk of this group's risk for non-fatal overdose.…”

“…Past research has identified a significant positive association between PO use (i.e., oral, intranasal, or intravenous administration) and non-fatal overdose (Lake et al, 2015), and has also found that among PO-using young adults, non-fatal overdose is more common among those who inject POs (Silva et al, 2013b). However, few studies have explored a potential independent association between PO injection and non-fatal overdose among PWID.…”

Illicit opioid use following changes in opioids prescribed for chronic non-cancer pain

“…[10] Qualitative studies have also described associations between a shortage of prescription OPRs and increased illicit opioid use. [11,12] Injection of illicit heroin is 3 times more risky for overdose than injection of OPRs [13,14] and fentanyl 4 times more risky than heroin. [15] This potential shift from prescribed to illicit opioids could partially account for the observed increase in opioid overdose mortality, despite various efforts to implement changes in opioid prescribing and management by health systems and providers.…”

Seeking prescription opioids from physicians for nonmedical use among people who inject drugs in a Canadian setting

“…The underlying explanation for this association requires further investigation. In particular, future research should examine the extent to which PO‐seeking behavior predicts riskier drug use practices that may increase the risk of overdose, such as polysubstance use, whether overdose predicts greater physician contact and PO‐seeking behavior or whether this association is explained by shared underlying risk factors for both PO‐seeking and overdose …”

“…PWID are known to commonly use POs for various reasons, including euphoria, pain relief, and management of withdrawal symptoms . Previous research suggests that PWID may be at a heightened risk of PO‐related harms, including overdose and infectious diseases such as HCV and HIV . Greater insight into the individual and social factors associated with seeking POs from physicians for nonmedical use may help to identify subpopulations of PWID who are at particularly high risk of PO‐related harms, providing critical knowledge to inform clinical and policy responses to PO misuse among this vulnerable population.…”