Trends in drug overdose deaths in Mexico (1999-2019). A national descriptive analysis and interstate comparison

Background: We assess trends in overdose mortality rates in Mexico from 1999 to 2019 and identify the states with the highest overdose mortality rates over time. Methods: The analysis using mortality statistics examined deaths related to drug use. We estimated general overdose mortality rates at the national and state levels and calculated specific mortality rates associated with opioid and stimulant use using central rate estimation. We used joinpoint regression to analyse national and state-specific trends in overdose mortality from 1999 to 2019. Findings: Nationally, the general overdose mortality rate increased annually by 10.49 % (p < 0.01, CI=11.4-18.9) from 2015 to 2019. The northern states of Baja California and Chihuahua were the states with the higher annual increases (18.6 %, p < 0.01, CI=4.2-29.6; and 15.6 %, p < 0.01, CI=12.9-19.7, respectively). By substance type, the national opioid-related mortality rate increased by 29.82 % per year from 2014 to 2019 (p < 0.01; CI=20.1-40.3), compared with an annual decrease of 11.43 % in the previous period (2005-2014) (p < 0.01; CI=-14.7- 8.0). Baja California was the state with the highest rise in opioid-related mortality from 2013 to 2019, with an annual increase of 15.84 % (p < 0.01; CI=1.4-32.3). Stimulant-related mortality increased by 21.79 % per year since 2013 (p < 0.01; CI=16.9-26.9), but it was not possible to calculate state-level trends. Conclusions: Drug-related mortality rates have increased in Mexico since 2015, particularly in the northern states of Baja California, Chihuahua, Sonora and Sinaloa. Improving harm reduction programmes and local surveillance of fatal and non-fatal overdoses is essential to address the silent escalation of overdose mortality.