Figure 1.

Opioid Use Subgroups.

¹Drug use was defined as self-reported use of an illegal drug or non-prescribed medication in the 90 days prior to study enrollment.

²Patients with any opioid use were those who self-reported using opioids one or more days in the past 30 days at baseline.

³Patients with no opioid use were those who did not report using an opioid in the 30 days prior to baseline.

⁴Patients in the non-prescribed opioid use subgroup included those who reported using heroin, methadone non-prescribed, or other opioid analgesics non-prescribed in the 30 days prior to baseline. Methadone as prescribed was always for pain treatment and not for opioid dependence.

⁵Patients with opioid use only as prescribed reported using opioids only according to the prescription in the 30 days prior to baseline. Methadone as prescribed was always for pain treatment and not for opioid dependence.