Infrequent opioid overdose risk reduction behaviours among young adult heroin users in cities with wide coverage of HIV prevention programmes.

BACKGROUND: Opioid overdose risk reduction behaviours include some preventive behaviours to avoid overdoses (PB) and others to avoid death after overdose, such as never using heroin while alone (NUA). Few studies have examined the prevalence and predictors of these behaviours. AIM: To establish the prevalence and predictors of PBs and NUA among heroin users, both injectors and non-injectors, in three Spanish cities.
METHODS: 516 injecting and 475 non-injecting heroin users aged 18-30 were street-recruited in 2001-2003 and interviewed by face-to-face computer-assisted interview. PBs and NUA in the last 12 months were explored using open-ended and precoded questions, respectively. Specific predictors for three PB categories were investigated: control of route of drug administration, control of quantity or type of heroin used, and control of co-use of other drugs. Bivariate and logistic regression methods were used.
RESULTS: Overall, the most prevalent PBs were: using a stable and not excessive amount of heroin (12.7%), injecting or using the whole heroin dose slowly or dividing it into smaller doses (12.4%), reducing or stopping heroin injection (8.3%), and not mixing heroin with tranquillisers (5.1%). Most PBs were significantly more prevalent among injectors than non-injectors. No one mentioned reducing the amount of heroin after an abstinence period. Some 36.2% had NUA. In multiple regression analysis, knowledge of risk factors for opioid overdose was a predictor of specific PBs, although this was not always the case. Use of syringe exchange programmes was a predictor of PB among injectors. However, attending methadone maintenance treatment (MMT) or other drug-dependence treatment was not a predictor of any opioid overdose reduction behaviour. Only ever having witnessed or experienced an overdose predicted PB in both injectors and non-injectors.
CONCLUSIONS: The proportion of heroin users with opioid overdose risk reduction behaviours is very low. Additional specific measures to prevent overdose are needed, as well as increased emphasis on reducing the risk of overdose in programmes to prevent HIV and other blood-borne infections in heroin injectors.