Differences in polysubstance use patterns and drug‐related outcomes between people who inject drugs receiving and not receiving opioid substitution therapies

Abstract

Polysubstance use profiles exhibiting a broad range of substance use were generally at increased risk of negative drug-related outcomes, whether or not participants were receiving OST, including thrombosis among OST receivers [odds ratio (OR) = 2.13, 95% confidence intervals (CI) = 1.09-4.17], injecting with used needles among OST receivers and non-receivers, respectively (OR = 2.78, 95% CI = 1.50-5.13; OR = 2.15, 95% CI = 1.34-3.45) and violent criminal offences among OST receivers and non-receivers, respectively (OR =2.30, 95% CI = 1.16-4.58; OR = 1.87, 95% CI = 1.14-3.07). An important exception was non-fatal overdose which was related specifically to a class of PWID who were not receiving OST and used morphine frequently (OR = 1.83, 95% CI = 1.06-3.17) CONCLUSION: Regardless of opioid substitution therapies usage, people who inject drugs who use a broad-range of substances experience greater levels of injecting-related injuries and poorer health outcomes and are more likely to engage in criminal activity than other groups of people who inject drugs.

Latent Risk Subtypes Based on Injection and Sexual Behavior Among People Who Inject Drugs in Rural Puerto Rico

“…Prior LCA research has found that older age decreases the odds of high-risk class membership, relative to lowerand moderate-risk classes. 24,26 These results also support non-LCA research in which younger age was associated with risky injection 46 and sexual behavior, 47 and other factors indirectly associated with injection and sexual risk behavior among PWID including poly-substance use 48 and homelessness. 47 Taken together, the associations between age and high-risk latent class membership may be a function of younger PWID being embedded in risk environments and social networks conducive to risk behavior.…”

Rural and urban comparisons of polysubstance use profiles and associated injection behaviors among people who inject drugs in Puerto Rico

“…A three-class solution was identified in the rural sample, and a five-class solution was identified in the urban sample, patterns similar to those found in prior LCA research with PWID (Betts et al, 2016; Harrell et al, 2012; Kuramoto et al, 2011; Meacham et al, 2015; Monga et al, 2007; Roy et al, 2013; Trenz et al, 2013). These patterns across diverse populations of PWID suggests that polysubstance use is normative (rather than restricted to a small subset) within the PWID population—and may reflect a common liability for polysubstance use among heavy substance users everywhere (Vanyukov et al, 2003).…”

“…In general, polysubstance use among PWID has been associated with distinct physical and mental health comorbidities (Betts et al, 2016; Patra et al, 2009), increased injection and sexual risk behaviors (Harrell et al, 2012; Meacham et al, 2015), and poorer treatment outcomes (Dutra et al, 2008). These factors may explain higher risks of overdose and HIV and HCV infection among polysubstance using PWID when compared to PWID who use a limited range of substances (Harrell et al, 2012; Keen et al, 2014).…”

“…LCA is a statistical method which aims to identify latent subgroups of individuals who share similar profiles on a set of observed variables (Collins and Lanza, 2013), and has recently been used to characterize polysubstance use among PWID outside of Puerto Rico (Betts et al, 2016; Hopfer et al, 2014; Meacham et al, 2015; Roth et al, 2015). LCA, however, has not been used previously to compare urban and rural PWID.…”

Patterns of substance use and mortality risk in a cohort of ‘hard‐to‐reach’ polysubstance users

“…The existing cross‐sectional LCA studies examining latent classes of substance use have reported significant associations with potential risk factors for premature death, such as non‐fatal overdose, hepatitis C status, high‐risk sexual practices and depressive symptoms . This set of studies indicates that there is an association between mortality and the more complex patterns of substance use identified through methods such as LCA.…”