Life expectancy of people who are dependent on opioids: a cohort study in New South Wales, Australia

Background
People who are dependent on opioids have substantially increased risk of premature death, but there are few estimates of life expectancy.

Methods
We calculated age-specific mortality rates in a cohort of people who had at least one prescription of an opioid agonist (methadone or buprenorphine) between 2001 and 2018 in New South Wales, Australia. We estimated life expectancy at age 18 based on life tables. We also estimated the potential years of life lost before age 75, decomposed by cause of death.

Results
The cohort included 47,197 people, with a median of 9.8 years of follow-up. 5,097 participants died, and the standardised mortality ratio (compared to the general population of New South Wales) was 6.06 (95% CI 5.90-6.23). Life expectancy at age 18 was 47.5 years (95% CI 42.9-50.5) for men and 50.7 years (95% CI 45.4-54.8) for women; deficits of 14.7 and 15.8 years respectively when compared to the general population. The largest cause of death was non-communicable physical diseases, which accounted for 47% of deaths in life tables for men and 42% for women. Drug-related deaths accounted for 16% of deaths for men and 19% for women, but due to the young age at which these deaths occur, they contributed approximately one third of potential years of life lost.

Conclusion
In common with people with serious mental illnesses, people who are dependent on opioids have substantially reduced life expectancy. In both populations most excess deaths relate to noncommunicable physical diseases.