Health care utilization prior to suicide in adults with drug use disorders

Drug use disorders (DUD) are associated with psychiatric illness and increased risks of suicide. We examined health care utilization prior to suicide in adults with DUD, which may reveal opportunities to prevent suicide in this high-risk population. A national cohort study was conducted of all 6,947,191 adults in Sweden, including 166,682 (2.4%) with DUD, who were followed up for suicide during 2002-2015. A nested case-control design examined health care utilization among persons with DUD who died by suicide and 10:1 age- and sex-matched controls from the general population. In 86.7 million person-years of follow-up, 15,662 (0.2%) persons died by suicide, including 1946 (1.2%) persons with DUD. Unadjusted and adjusted relative risks of suicide associated with DUD were 11.03 (95% CI, 10.62-11.46) and 2.84 (2.68-3.00), respectively. 30.4% and 52.3% of DUD cases who died by suicide had a health care encounter within 2 weeks or 3 months before the index date, respectively, compared with 5.9% and 24.3% of controls (unadjusted prevalence ratio and difference, <2 weeks: 5.20 [95% CI, 4.76-5.67] and 24.6 percentage points [22.5-26.6]; <3 months: 2.15 [2.05-2.26] and 27.9 [25.6-30.2]). However, after adjusting for psychiatric comorbidities, these differences were much attenuated. Among DUD cases, 72.5% of last encounters within 2 weeks before suicide were in outpatient clinics, mostly for non-psychiatric diagnoses. In this large national cohort, suicide among adults with DUD was often shortly preceded by outpatient clinic encounters. Clinical encounters in these settings are important opportunities to identify suicidality and intervene accordingly in patients with DUD.