法執行による薬物市場の混乱が過剰摂取に及ぼす影響を探る時空間分析、インディアナ州インディアナポリス、2020-2021年 Spatiotemporal Analysis Exploring the Effect of Law Enforcement Drug Market Disruptions on Overdose, Indianapolis, Indiana, 2020–2021
Bradley Ray, Steven J. Korzeniewski, George Mohler, Jennifer J. Carroll, Brandon del Pozo, Grant VictorD, Philip Huynh, and Bethany J. Hedden
American Journal of Public Health Published: June 07, 2023
Objectives. To test the hypothesis that law enforcement efforts to disrupt local drug markets by seizing opioids or stimulants are associated with increased spatiotemporal clustering of overdose events in the surrounding geographic area.
Methods. We performed a retrospective (January 1, 2020 to December 31, 2021), population-based cohort study using administrative data from Marion County, Indiana. We compared frequency and characteristics of drug (i.e., opioids and stimulants) seizures with changes in fatal overdose, emergency medical services nonfatal overdose calls for service, and naloxone administration in the geographic area and time following the seizures.
Results. Within 7, 14, and 21 days, opioid-related law enforcement drug seizures were significantly associated with increased spatiotemporal clustering of overdoses within radii of 100, 250, and 500 meters. For example, the observed number of fatal overdoses was two-fold higher than expected under the null distribution within 7 days and 500 meters following opioid-related seizures. To a lesser extent, stimulant-related drug seizures were associated with increased spatiotemporal clustering overdose.
Conclusions. Supply-side enforcement interventions and drug policies should be further explored to determine whether they exacerbate an ongoing overdose epidemic and negatively affect the nation’s life expectancy. (Am J Public Health. 2023;113(7):750–758. https://doi.org/10.2105/AJPH.2023.307291)
The overdose epidemic has accounted for nearly 1 million lives lost in the United States in the past 2 decades.1 Although the majority of overdose deaths are opioid related, the type of opioid involved and corresponding mortality rates vary over time, with fentanyl presently driving the fatality count in opioid- and stimulant-involved overdose deaths alike.2,3 Emergency medical services (EMS) are typically deployed in response to overdose and poisoning calls for service, and EMS administer naloxone (an opioid antagonist) when indicated to reverse respiratory depression caused by opioids. Although there are substantial geographic and policy differences in who administers naloxone and under what circumstnaces,4 the number of EMS naloxone administrations per capita are increasingly used for public health surveillance purposes5 and to guide resource allocation.6 However, the search continues to identify factors that reliably precede overdoses to trigger and inform targeted prevention efforts.7–9 We explored law enforcement drug market disruptions as a potential factor.
People can develop a tolerance for opioids, although overdose occurs when dosage exceeds tolerance to the point of respiratory failure. Unknown opioid tolerance at relapse is a documented overdose risk factor among the recently incarcerated10,11 and those discharged from residential treatment and withdrawal management settings.12,13 Reductions in tolerance can occur after any involuntary disruption of an individual’s opioid supply, and accidentally ingesting a dose beyond one’s tolerance can be fatal. This mechanism accounts for the second wave of the overdose epidemic, when consumers shifted from pharmaceutical opioids to heroin. Heroin is a much less consistent and predictable product, increasing the dangers that come of unknown tolerance, especially overdose risk.2,14
This same mechanism has been documented as occurring in the illicit drug market following disruptions from an arrested supplier and consumers contending with new and potentially unfamiliar products.15,16 The impact of these drug market disruptions may be particularly salient for people who use opioids, who can experience painful withdrawal symptoms and diminished biological tolerance even after short periods of abstinence.13 There is also a risk for people who knowingly use stimulants but are opioid naïve and, thus, have lower opioid tolerance; they might seek a new supplier following a drug market disruption and then overdose from fentanyl-contaminated stimulants.3
We tested the hypothesis that law enforcement efforts to disrupt local drug markets through routine supply-side interdictions—as measured by police seizures of opioid- and stimulant-related substances—are associated with increased spatiotemporal clustering of fatal and nonfatal overdoses, as well as increases in EMS naloxone administration, in the area surrounding the seizure. Although the analytical methods we employed cannot establish causality, we hypothesized that the causal mechanism for an association lies in the disruption of a person’s ability to obtain a substance they can accurately dose; this is because that supply has become unavailable, resulting in their transition to an alternate supply with no knowledge of its potency or their ensuing tolerance.11,13,15 Given the potential for withdrawal and overdose because of unknown tolerance among opioid users, we hypothesized an association with EMS naloxone administration following opioid-related seizures. But with the potential for unintentional opioid consumption among stimulant users, we also explored naloxone administration associated with stimulant-related seizures.