Table 2.
Variables and response options to be examined in association with pharmaceutical opioid-related ambulance attendances
| Variable | Response options |
| Presenting Glasgow Coma Scale | 3 (non-responsive), 4–8 (severe impairment), 9-12 (moderate impairment), 13–15 (minor-no impairment) |
| Presenting respiratory rate (breaths per min) | <6, 6–12, >12 |
| Transport to hospital | Not transported, transported |
| Naloxone administered: not stated, yes | Not stated, yes |
| Naloxone response: not effective, effective | Not effective, effective |
| Sex of patient | Male, female, other/unspecified |
| Age of patient | 12–34, 35–54, 55–65 (nearing retirement age) and 65+* |
| Socioeconomic status based on residential postcode | Quintile 1–5 based on SEIFA-IRSD 201 s, IRSD 201638 |
| Concurrent alcohol involvement | Not stated, alcohol involved but no evidence of intoxication, alcohol intoxication† |
| Concurrent heroin involvement | Not stated, present |
| Concurrent illicit drug use (excluding heroin) | Based on the presence of at least one of the illicit drugs coded for meth(amphetamine), cannabis, synthetic cannabinoids, emerging psychoactive substances, cocaine, 3,4-methylenedioxy-methamphetamine (MDMA), gamma-hydroxybutyrate, ketamine, Lysergic acid diethylamide (LSD), psilocybin, inhalant, illicit drug other or unspecified) |
| Concurrent non-opioid extramedical pharmaceutical use | Not stated, present (based on the presence of at least one of the pharmaceutical groups coded for non-opioid analgesics, benzodiazepines, antidepressants, antipsychotics, anticonvulsants, opioid-dependence treatments, pharmaceutical stimulants, other medication) |
| Comorbid mental health symptoms | Not stated, present (based on the presence of at least one of symptoms of anxiety, depression, psychosis, social/emotional distress, symptoms associated with disorders with clinical evidence and mental health unspecified) |
| Comorbid suicidal thoughts or behaviours | Not stated, present (based on the presence of at least one of suicidal ideation, suicide attempt) |
| Comorbid non-suicidal self-injury | Not stated, present (based on the presence of at least one of threat of non-suicidal self-injury, non-suicidal self-injury) |
| Accidental overdose | Not stated, yes |
| Unknown intent overdose‡ | Not stated, yes |
| History of psychiatric issues | Not stated, present (based on the presence of at least one of history of mood disorder, psychosis, suicidal ideation, suicide attempt, alcohol and other drug misuse) |
*Based on previous age categories used in studies of opioid use for pain.39 We will exclude cases where age is reported to be <12 years due to the unclear intention of use in children of this age, consistent with previous research.40 41
†The involvement of alcohol is coded as ‘alcohol involved’ and ‘alcohol intoxication’. Attendances where the person has consumed alcohol, but the paramedic notes do not clearly indicate alcohol intoxication are coded as ‘alcohol involved’ and ‘alcohol intoxication is a subset of ‘alcohol involved’. The default code is for ‘alcohol involved’ unless the paramedic notes provide clear evidence of alcohol intoxication.
‡Where information provided in the patient care records by the paramedic means that the coding team cannot determine if the overdose was accidental or if there was suicidal intent.