Xylazine-involved fatal overdoses and localized geographic clustering: Cook County, IL, 2019-2022.

BACKGROUND: Xylazine, a veterinary analgesic sedative, is circulating in the illicit drug markets of at least 23 states including Illinois. We conducted a geographic analysis to better identify the spatial distribution of xylazine-involved fatal overdoses in Cook County, IL. METHODS: Cook County Medical Examiner Office's (CCMEO) publicly available data was used to identify xylazine-involved fatal overdoses from January 1, 2019, to June 30, 2022. Xylazine-positive (cases) to xylazine-negative groups with drug mixtures involving fentanyl, alcohol and stimulants (controls) were matched on age, race, sex, and year of death. Ripley's K-function was used to examine the likelihood of case clustering compared to controls with the Bernoulli spatial scan deployed to identify specific geographic clusters. RESULTS: Almost all (94.4%) xylazine-positive overdoses contained fentanyl. Using coordinate-based matching, we found that approximately 3% of xylazine overdose incidents were co-located with other overdoses. Xylazine cases clustered to from 0 to 16.1 miles (max=10.6 miles). Results of the Bernoulli spatial scan varied by control group with two high-risk clusters found relative to alcohol and stimulants and a low-risk cluster relative to fentanyl. Differences in co-occurring drugs were found between xylazine and fentanyl groups like the absolute number of drugs (4.6v 3.4, p<0.0001) and fentanyl analog types. CONCLUSIONS: Xylazine fatal overdose incident locations exhibited localized clustering relative to fentanyl overdoses but clusters were not precisely detected at these scales. Even so, our results, especially relative to repeat overdose micro "hot spots", offer insight on targeting harm reduction and other services at the neighborhood-level.

Evaluating the Reliability of Dipstick Drug Screens on Vitreous and Postmortem Blood as a Triage Modality in Forensic Pathology.

Dipstick drug screens are cheap, easy to use, and quick presumptive tests to detect common drugs of abuse. Dipsticks are designed for drug detection in urine. There is no literature regarding their potential use on fluids different from urine. The study aimed to determine the performance of dipstick screening tests on postmortem vitreous and blood specimens compared to urine dipsticks and final confirmatory toxicology analyses on blood. The study population included cases in which a complete toxicology analysis was performed. Each subject was screened for three substances: cocaine, fentanyl, and opiates. Dipstick results were checked by visual inspection. Results were compared with urine screening tests and quantitative, confirmatory toxicological analyses by gas chromatography/mass spectrometry on postmortem blood samples as the gold standards for screening and confirmatory analysis, respectively. There was a high number of false-negative results for opiates. Cocaine dipsticks in blood showed the highest reliability. Fentanyl dipsticks in vitreous showed a high number of false-negative results. Both vitreous and blood dipstick screening tests for all substances performed well on negative cases. When both blood and vitreous screening tests are negative, the chance that the confirmatory toxicology analysis will be positive is very low.

geoPIPE: Geospatial Pipeline for Enhancing Open Data for Substance Use Disorders Research.

We present our open-source pipeline for quickly enhancing open data sets with research-focused expansions and show its effectiveness on a cornerstone open data set released by the Cook County government in Illinois. The City of Chicago and Cook County were both early adopters of open data portals and have made a wide variety of data available to the public; we focus on the medical examiner case archive which provides information about deaths recorded by Cook County's Office of the Medical Examiner, including overdoses invaluable to substance use disorder research. Our pipeline derives key variables from open data and links to other publicly available data sets in support of accelerating translational research on substance use disorders. Our methods apply to location-based analyses of overdoses in general and, as an example, we highlight their impact on opioid research. We provide our pipeline as open-source software to act as open infrastructure for open data to help fill the gap between data release and data use.

Opioid Overdoses Increase at Home During the COVID-19 Stay-At-Home Order Period in Cook County, Illinois.

Introduction: Stay-at-home orders during the COVID-19 pandemic decreased population mobility to reduce SARS-CoV-2 infection rates. We empirically tested the hypothesis that this public health measure was associated with a higher likelihood of opioid- and stimulant-involved deaths occurring in homes located in Cook County, Illinois. Methods: The stay-at-home period was from March 21, 2020 to May 30, 2020. We analyzed overdose data from the Cook County Medical Examiner's Office using a death location description from case investigations categorized as home, medical, motel, scene, and other. Two groups of decedents were defined as either having an opioid or stimulant listed in the primary cause of death field. We modeled a weekly time series to detect changes in deaths (number) and trends during segmented time periods. Chi-square or Fisher's exact and adjusted logistic regression was used for testing the differences between the stay-at-home and a 13-week preceding period. Results: There were 4,169 and 2,012 opioid- and stimulant-involved deaths, respectively, from 2018 to 2020. Both groups were demographically similar: 75% male, 52% White, and aged 45 years (mean). In the 13 weeks before stay-at-home orders, 51% of opioid-involved deaths occurred in homes, which increased to 59% (p<0.0001) during the 10 weeks of the order and decreased back to 51% in the 18 weeks after the order expired. For stimulant-involved deaths, 51% were residential immediately before the orders, with a nonsignificant increase to 52% during the stay-at-home period. Before the pandemic, there were 20 deaths/week, increasing to 37 deaths/week (p<0.0001) during stay-at-home enactment. Deaths involving fentanyl among the opioid-involved group increased from 76% to 89%, whereas those involving heroin decreased from 55% to 37%. The adjusted OR for opioid-involved fatal overdoses occurring at home during this period compared with that occurring the 13 weeks before was 1.37 (95% CI=1.05, 1.79). Conclusions: The likelihood of a death occurring at home, especially for people using opioids, increased during the stay-at-home order period. Findings have implications for mitigating overdose risks during social isolation.