Bayesian spatial analysis of age differences and geographical variations in illicit-drug-related mortality in the Islamic Republic of Iran

Abstract

Drug use disorders are significant social and public health concerns in the Islamic Republic of Iran; however, little is known about drug-related mortality. We quantified the spatial and age distribution of direct illicit-drug-related mortality in the Islamic Republic of Iran, to inform harm reduction policies and interventions. We modelled and mapped registered illicit-drug-related deaths from March 2016 to March 2017. Data were obtained from the Iranian Forensic Medicine Organization. Besag-York-Mollie models were fitted using Bayesian spatial analysis to estimate the relative risk of illicit-drug-related mortality across different provinces and age groups. There were 2203 registered illicit-drug-related deaths during the study period, 1289 (58.5%) occurred in people aged 20-39 years and among men (n = 2013; 91.4%). The overall relative risk (95% credible interval) of illicit-drug-related mortality in the provinces of Hamadan (3.37; 2.88-3.91), Kermanshah (1.90; 1.55-2.28), Tehran (1.80; 1.67-1.94), Lorestan (1.71; 1.37-2.09), Isfahan (1.40; 1.21-1.60), and Razavi Khorasan (1.18; 1.04-1.33) was significantly higher than in the rest of the country. We found evidence of age differences and spatial variations in illicit-drug-related mortality across different provinces in the Islamic Republic of Iran. Our findings highlight the urgent need to revisit existing drug-use treatment and harm reduction policies and ensure that overdose prevention programmes are adequately available for different age groups and settings.