What are the indirect causes of death among people who use drugs in Ireland? Findings from a comprehensive special register on drug related deaths
Background: Globally, people who use drugs are at a higher risk of premature death due to chronic illness or trauma. This group is also at a higher risk of suicide. Most of the research on this subject has been taken from general mortality registers or once-off studies. The National Drug-Related Deaths Index (NDRDI) is Ireland’s special register on drug-related deaths and deaths among people who use drugs, which aims to be a census of all such deaths in the country annually. It records both direct and indirect causes of death.
Methods: The strength of the Index is that it collects information from four national data sources, with the main source being the Coronial Service. The other sources are: the General Mortality Register, inpatient hospital mortality and the register of clients on opioid substitution treatment. This allows identification of deaths among people who use drugs, regardless of the cause of death. Data on each person is matched across all four sources to provide a comprehensive amount of information on the characteristics of those who died and their cause of death.
Between 2004 and 2016, there were 8,211 deaths which met the inclusion criteria for the NDRDI. Of these, 3,614 (44%) were classified as a non-poisoning death i.e. not due to an overdose. The number of non-poisoning deaths have increased from 165 deaths in 2004 to 386 deaths in 2016. The majority (79%) were male. Non-poisoning deaths are equally divided between two broad categories: deaths due to medical or traumatic causes. Those who died of a traumatic cause were generally younger (median age 34 years) then those who died of medical causes (median age 45 years), although over the period the overall age has increased. Over the period, deaths due to hanging were the most common cause of non-poisoning death, rising from 30 deaths (18%) in 2004 to 96 deaths (25%) in 2016. The most common drugs used in this group were cocaine and cannabis. In 2016, 74% of those who died due to hanging had a history of mental health problems. The next most common causes were cardiac causes followed by liver disease.
Discussion: Data from the Irish special register allows a more in depth and complete analysis of the direct and indirect consequences of drug use on the population, showing clearly the burden of premature mortality among people who use drugs. This can help formulate, and measure policies to reduce deaths among people who use drugs.