Abstract

Background Alcohol (AUD), opioid (OUD) and other substance use disorders (SUD) are associated with an increased risk of premature death. The aim of this register-based follow-up study was to compare the risk of death between individuals who had sought treatment for AUDs, OUDs and other SUDs in Finland.

Design, setting, participants Data included 10,888 individuals who had sought help from three clinics at some point between 1990 and 2009. Treatment data were linked to national register data concerning education, hospitalizations and death by the year 2018.

Measurements Individuals were categorized into four groups: only alcohol (AUD-only), all OUDs (OUD-all), other or multiple SUDs (SUD-other) and outpatients without substance-related diagnoses or hospitalizations (SU-NAS); in mortality analyses, those who had started in opioid substitution treatment (OST) were analyzed separately. COX regression analyses were used to calculate the risk of death by the year 2018 or up to 15 years after seeking treatment.

Results Among the 10,888 treatment-seeking individuals the cumulative mortality rates during 1-, 5- and 15-year follow-up were 2.5% (n = 271), 10.9% (n = 1191) and 28.4% (n = 3096), respectively. The mean age at death varied according to substance of use (55.0 years for AUD-only, 35.8 OUD-all, 45.8 SUD-other and 55.6 SU-NAS). The patients who had started in OST had a lower risk of death compared to the other groups, as did the SU-NAS group that likely included individuals with a less severe course of AUDs/SUDs. There were no differences between the AUD-only, OUD-other and SUD-other groups for the risk of death during the 15-year follow-up period when gender and year of birth were included as covariates.