TABLE 3.

Items and definitions for the OUD–COS (version 1.0)

Type	Measure	Definition/wording
PRO	Patient global impression of improvement (PGI‐I) [31]	After a specified start date to end‐point or specified period of enrollment in MOUD or MOUD‐PSI: ‘compared to how you were before you started treatment, how are your opioid problems now?’ Response options (scoring): very much better (7); much better (6); a little better (5); no change (4); a little worse (3); much worse (2); very much worse (1)
PRO	Non‐fatal opioid overdose [32, 33, 34]	After a specified start date to end‐point or specified period of enrollment in MOUD or MOUD‐PSI: record the number of times the patient reports experiencing (or is witnessed by others to experience) of accidental, intentional or undetermined overdose after ingestion of drugs known or believed to contain opioids. This measure should specify the appropriate ICD‐10 (F10–19 requiring F11) and T‐codes
ObsRO	Illicit/non‐medical drug toxicology	After a specified start date to end‐point or specified period of enrollment in MOUD or MOUD‐PSI: the patient is defined as a ‘treatment responder’ if, in the past 21 days, they provide at least two urine drug screening tests in different weeks that are negative for opioids
PerfO	Duration of treatment	After a specified start date to end‐point or specified period of enrollment in MOUD or MOUD‐PSI: the number of days of continuous treatment from the first date of a specified type of MOUD (or all types) received by the patient to the last day of the patient's prescription. NB: treatment is continuous if there is no more than 30 days last expected day of dosing to account for medication re‐starting or transfers between providers
PerfO	Fatal opioid poisoning [32, 33, 34]	At any time during enrollment in MOUD or MOUD‐PSI: this is death from accidental or intentional ingestion of drugs, specifying the ICD‐10 F11 and X‐codes, as follows: one or more opioids are recorded, were determined or mentioned on the death certificate; ‘mental and behavioral disorders due to drug use’ (F11–F16, F18, F19); F11 must be present; and one or more of the following: ‘accidental poisoning by drugs, medicaments and biological substances’ (X40–X44); ‘intentional self‐poisoning by drugs, medicaments and biological substances’ (X60–X64); ‘assault by drugs, medicaments and biological substances’ (X85); or ‘poisoning by drugs, medicaments and biological substances, undetermined intent’ (Y10–Y14). ‘All‐cause’ mortality should also be reported if feasible

OUD = opioid use disorder; OUD–COS = opioid use disorder–core outcome set; MOUD = medications for OUD; PRO = patient‐reported; ObsRo = observer‐reported; PerfRO = performance outcomes; PSI = psychosocial interventions.