A recently published study from Karolinska Institutet shows that mortality among people who inject drugs enrolled in the Stockholm needle and syringe program declined over a ten-year period, with a marked reduction in opioid overdose deaths. The study is published in Harm Reduction Journal, and the findings coincide with a period of expanded harm reduction interventions, including the implementation of a take-home naloxone program.
People who inject drugs face a substantially elevated risk of premature mortality, often due to overdose. In a new study, researchers at Karolinska Institutet followed 4,192 individuals who attended the Stockholm needle and syringe program between 2013 and 2023 and linked data from the program's quality register with the Swedish National Cause of Death Register.
A total of 685 individuals died during the study period, corresponding to 16 percent of the cohort. All-cause mortality declined over time, with the largest change observed in opioid overdose deaths.
Marked decline in opioid overdose mortality
Opioid overdose was the leading cause of death, accounting for 53 percent of all deaths. At the same time, opioid overdose mortality decreased from 29.40 to 5.88 deaths per 1,000 person-years during the study period.
This decline coincided with the introduction of take-home naloxone distribution at the Stockholm needle and syringe program in January 2018, as well as with reduced reported opioid use among program participants.
"We observe a clear decline in opioid overdose deaths over time. This strengthens the evidence that broader access to harm reduction interventions can make a difference," says Elin Holmén , researcher at the Centre for psychiatry research, Department of clinical neuroscience , Karolinska Institutet.
Factors associated with risk
In the analyses, reporting opioid use was the strongest predictor of both all-cause mortality and opioid overdose death. Less frequent injecting and recent detoxification were also associated with increased risk.
Participation in opioid agonist therapy, by contrast, was associated with a lower risk of both all-cause mortality and opioid overdose death.
"The results underline the importance of continuing to scale up opioid agonist therapy and ensuring that naloxone is readily available in high-risk settings, as these interventions can save lives," says Elin Holmén.
Changing causes of death over time
While opioid overdose deaths declined, mortality from disease-related causes, so-called natural causes, increased over the same period. This may indicate a growing need for broader health interventions for an ageing and medically vulnerable population, beyond measures directly targeting overdose risk.
The researchers also note that supervised consumption sites, where drugs can be used under medical supervision, may represent a complementary intervention to further prevent deaths.
The authors report no competing interests. The study was funded by ALF and the Swedish Research Council for Health, Working Life and Welfare (Forte).
Publication
'All-cause mortality and overdose deaths among 4,192 people who inject drugs in Stockholm: a 10-year register-based cohort study' , Elin Holmén, Anders Hammarberg, Martin Kåberg, Harm Reduction Journal, online 13 February 2026, doi: 10.1186/s12954-026-01407-z.
