Prevalence and determinants of opioid use disorder among long-term opiate users in Golestan Cohort Study.

backgroundNumber of opiate users worldwide has doubled over the past decade, but not all of them are diagnosed with opioid use disorder. We aimed to identify the prevalence and risk factors for OUD after ten years of follow-up.

methodsAmong 8,500 chronic opiate users at Golestan Cohort Study baseline (2004-2008), we recalled a random sample of 451 subjects in 2017. We used three questionnaires: a questionnaire about current opiate use including type and route of use, the drug use disorder section of the Composite International Diagnostic Interview lifetime version, and the validated Kessler10 questionnaire. We defined opioid use disorder and its severity based on the DSM-5 criteria and used a cutoff of 12 on Kessler10 questionnaire to define psychological distress.

resultsMean age was 61.2 ± 6.6 years (84.7% males) and 58% were diagnosed with opioid use disorder. Starting opiate use at an early age and living in underprivileged conditions were risk factors of opioid use disorder. Individuals with opioid use disorder were twice likely to have psychological distress (OR = 2.25; 95%CI: 1.44-3.52) than the users without it. In multivariate regression, former and current opiate dose and oral use of opiates were independently associated with opioid use disorder. Each ten gram per week increase in opiate dose during the study period almost tripled the odds of opioid use disorder (OR = 3.18; 95%CI: 1.79-5.63).

conclusionsChronic opiate use led to clinical opioid use disorder in more than half of the users, and this disorder was associated with psychological distress, increasing its physical and mental burden in high-risk groups.