Estimating changes in overdose death rates from increasing methamphetamine supply in Ohio: Evidence from crime lab data.

Background: We investigate the relationship between the supply of methamphetamine and overdose death risk in Ohio. Ohio and the overall US have experienced a marked increase in overdose deaths from methamphetamine combined with fentanyl over the last decade. The increasing use of methamphetamine may be increasing the risk of overdose death. However, if people are using it to substitute away from more dangerous synthetic opioids, it may reduce the overall risk of overdose death. Methods: Ohio's Bureau of Criminal Investigation's crime lab data include a detailed list of the content of drug samples from law enforcement seizures, which are used as a proxy for drug supply. We use linear regressions to estimate the relationship between the proportion of methamphetamine in lab samples and unintentional drug overdose death rates from January 2015 through September 2021. Results: Relatively more methamphetamine in crime lab data in a county-month has either no statistically significant relationship with overdose death rates (in small and medium population counties) or a negative and statistically significant relationship with overdose death rates (in large population counties). Past overdose death rates do not predict future increases in methamphetamine in crime lab data. Conclusions: The results are consistent with a relatively higher supply of methamphetamine reducing the general risk of overdose death, possibly due to substitution away from more dangerous synthetic opioids. However, the supply of methamphetamine appears unrelated to the past illicit drug risk environment. The non-lethal and yet serious health effects of MA use were not explored and, thus, even if the presence of MA reduces the population-level overdose mortality rate, the rise of other adverse health effects may counteract any public health benefits of fewer deaths.

Association between law enforcement seizures of illicit drugs and drug overdose deaths involving cocaine and methamphetamine, Ohio, 2014-2019.

BACKGROUND: The United States continues to experience a crisis of mounting opioid overdose deaths involving cocaine and methamphetamine (hereafter illicit stimulants). Law enforcement drug seizure data present a unique opportunity to examine the association between illicit-stimulant-involved overdose deaths (ISODs) and the illicit drug supply. Our objective is to better understand correlations between illicit drug market trends and increases in ISODs in Ohio in 2014-2019. METHODS: This observational study analyzes the universe of ISODs and drug seizures in Ohio from 2014 to 2019. We use graphs and descriptive statistics to characterize trends over time and estimate a time series model of their association. ISODs were summed to yield monthly statewide counts of seizures containing methamphetamine, cocaine, illicitly manufactured fentanyl (IMF), and other non-IMF opioids (e.g., heroin). All rates were calculated per 100,000 persons. RESULTS: Roughly 80% of ISODs in Ohio from 2014 to 2019 involved an opioid, with IMF co-occurring in 90% of ISODs by 2019. Methamphetamine and cocaine seizures containing IMF were associated with 0.439 (p < .01) and 0.457 (p < .01) additional deaths per 100,000 persons per month, respectively. IMF seizures not containing cocaine nor methamphetamine were also associated with additional ISODs (0.119, p < .01) and seizures of illicit stimulants not containing IMF were not associated with ISODs. CONCLUSIONS: The number of ISODs was extremely high when IMF was co-involved and relatively low without IMF involvement. By demonstrating how supply-side trends correspond with ISOD rates, the current study bolsters the analytical utility of law enforcement seizures and complements growing literature in the field.

Street-drug lethality index: A novel methodology for predicting unintentional drug overdose fatalities in population research.

BACKGROUND: Emerging evidence suggests the composition of local illicit drug markets varies over time and the availability and relative lethality of illicit drugs may contribute to temporal trends in overdose mortality. Law enforcement drug seizures represent a unique opportunity to sample the makeup of local drug markets. Prior research has associated shifts in the types of drugs seized and trends in unintentional drug overdose mortality. The present report builds on this work by demonstrating a novel methodology, the Street-Drug Lethality Index, which may serve as a low-lag predictor of unintentional overdose deaths. METHODS: Data included administrative records of law enforcement drug seizures and unintentional drug overdose deaths in Ohio from 2009 -to- 2018. Death records and lab results from drug seizures occurring during the calendar year 2017 were transformed via the described procedure to create lethality indices for individual drugs. These indices were then summed annually to create the independent variable for a linear regression model predicting unintentional overdose deaths for all years during the study period. RESULTS: The regression model explained 93 % of the year-to-year variance in unintentional overdose fatalities (slope = 0.009480; CI = 0.007369 to 0.011590; t10 = 10.355942; P = 0.000007; Y = 11.808982 + 0.009480X, r2 = 0.931). CONCLUSION: These findings contribute to a growing body of evidence that changes in the composition of the drug supply may predict trends in unintentional overdose mortality. The proposed methodology might inform future overdose prevention and response efforts as well as research.