Factors associated with chronic pain and non-medical opioid use among people who inject drugs

Introduction: Despite rising morbidity and mortality from the opioid epidemic and other addictions, people who inject drugs (PWID) remain understudied regarding pain outcomes. Data among PWID regarding chronic pain and drug use, including non-medical use of opioids, is largely unknown. We examined the prevalence of chronic pain and drug use for pain in this population. Methods: Standardized surveys captured self-report of demographics, chronic pain, and non-prescription drug use in 203 PWID in an urban syringe services program between April and November 2016. Chronic pain was defined as self-report of chronic pain diagnosis or persistent pains over the past 6 months. Results: Overall, 47% (95% CI, 40%-54%) of PWID reported chronic pain, while 35% (95% CI, 29%-42%) reported non-prescription drug use of any type for pain. Among those with chronic pain, drug use to treat pain was commonly reported (76%; 95% CI, 66%-83%). Non-medical opioid use did not differ among PWID with or without chronic pain or drug use for pain. A multivariable logistic regression model showed chronic pain was more likely among non-Hispanic whites and those with arthritis, older age, and homelessness. Conclusions: Chronic pain serves as an important factor in the persistence of drug use in more than one-third of PWID in this sample. The high prevalence of chronic pain with drug use for pain suggests that proper pain management is likely to be an essential component of preventing or regressing injection drug use in PWID, with data needed on effective interventions for this population.