Data quality considerations when using county-level opioid overdose death rates to inform policy and practice

Racial/ethnic inequality in homelessness and drug overdose deaths in US States

PURPOSE

This study examined whether state-level racial disproportionality in homelessness is associated with racial disproportionality in overdose mortality.

METHODS

Counts of individuals experiencing homelessness (2015-2017; by state and racial/ethnic group) were obtained from the US Department of Housing and Urban Development; population estimates and counts of drug overdose deaths (2018-2021; by state and racial/ethnic group) were obtained from the National Center for Health Statistics. Homelessness and overdose mortality disproportionality scores were calculated to indicate the extent to which each racial group was over- or under- represented among those experiencing homelessness, or among overdose deaths, respectively (relative to each racial group's proportional share in the general population). For each racial group examined, ordinary least squares regression models with robust standard errors (SEs) examined associations between state-level disproportionality in homelessness and disproportionality in overdose mortality, adjusting for percent aged 18-64 and US Census Region, as well as disproportionality in educational attainment and unemployment.

RESULTS

State-level racial disproportionality in homelessness was significantly and positively associated with racial disproportionality in overdose mortality for Black (b = 0.16 [SE = 0.05]; p < .01), American Indian/Alaska Native (b = 0.71 [SE = 0.23]; p < .01), and Hispanic populations (b = 0.17 [SE = 0.05]; p < .01), in models adjusting for region and percent aged 18-64. The significant positive associations in these three populations persisted after adjusting for educational attainment disproportionality, yet the association was no longer significant in the Black population after adjusting for unemployment disproportionality.

CONCLUSION

States with the highest levels of racial/ethnic minority overrepresentation in homelessness generally also had relatively higher levels of racial/ethnic minority overrepresentation in overdose deaths.

Forecasting drug-overdose mortality by age in the United States at the national and county levels

The drug-overdose crisis in the United States continues to intensify. Fatalities have increased 5-fold since 1999 reaching a record high of 108,000 deaths in 2021. The epidemic has unfolded through distinct waves of different drug types, uniquely impacting various age, gender, race, and ethnic groups in specific geographical areas. One major challenge in designing interventions and efficiently delivering treatment is forecasting age-specific overdose patterns at the local level. To address this need, we develop a forecasting method that assimilates observational data obtained from the CDC WONDER database with an age-structured model of addiction and overdose mortality. We apply our method nationwide and to three select areas: Los Angeles County, Cook County, and the five boroughs of New York City, providing forecasts of drug-overdose mortality and estimates of relevant epidemiological quantities, such as mortality and age-specific addiction rates.

Drug supply measures and drug overdose mortality in the era of fentanyl and stimulants

Background

Illicitly-manufactured fentanyl and stimulants have replaced prescription opioids as the primary contributors to fatal overdoses in the United States (US), yet the street supply of these substances is challenging to quantify. Building on the foundation of prior research on law enforcement drug reports, the present study compares publicly available forensic laboratory drug report measures to identify which measures account for the most variation in drug overdose mortality between states, within states over time, and in various demographic groups.

Methods

Drug reports from the National Forensic Laboratory Information System and drug overdose mortality rates from the Centers for Disease Control and Prevention were examined for all US states and the District of Columbia, 2013-2021 (459 state-years). State- and year- fixed effects models regressed drug overdose mortality rates (in the overall population and subpopulations by sex, age, and race/ethnicity) on various drug report measures, including rates per population and proportional shares of drug reports positive for fentanyl/fentanyl-related compounds, heroin, cocaine, methamphetamine, and xylazine.

Results

For drug overdose death rates in the overall population and nearly all subpopulations examined by sex, race/ethnicity, and age, the model including all drug report proportional measures represented the best-performing model (as identified via the lowest Akaike Information Criterion and highest within R-squared value), followed by the model including only the fentanyl/fentanyl-related compounds proportion.

Conclusions

Findings support the utility of publicly available drug report composition measures, particularly the proportion of fentanyl/fentanyl-related compounds, as predictors of drug overdose mortality in the US and in various subpopulations.

State-level homelessness and drug overdose mortality: Evidence from US panel data

BACKGROUND

Although homelessness is a well-documented risk factor for drug overdose at the individual level, less is known about state-level homelessness and overdose mortality in the United States (US).

METHODS

This study used 2007-2020 panel data for all US states and the District of Columbia, from the following sources: US Department of Housing and Urban Development (homelessness data); Centers for Disease Control and Prevention (drug overdose death counts, population estimates, and opioid prescribing rates); Bureau of Labor Statistics (unemployment rates); and the National Forensic Laboratory Information System (drug seizure data). Two-way (state and year) fixed effects models regressed log-transformed drug overdose mortality rates on homelessness prevalence, in nested models adding demographic composition and unemployment measures, as well as drug supply measures. Models were weighted by state population size, and standard errors (SEs) were clustered at the state level.

RESULTS

Homelessness prevalence was significantly and positively associated with rates of drug overdose mortality after adjusting for nationwide trends, time-invariant differences between states, demographic composition, and unemployment rates (b[SE]=0.98[0.36], p=0.009). The positive association between homelessness prevalence and overdose mortality was attenuated at higher levels of fentanyl availability (fentanyl involvement in drug seizures; interaction term b[SE]=-0.02[0.01], p=0.001).

CONCLUSION

The positive association between state-level homelessness and drug overdose mortality suggests that policies and programs to prevent and reduce homelessness represent fundamental elements of a comprehensive response to the US overdose crisis.

Xylazine in Drug Seizure Reports and Overdose Deaths in the US, 2018-2022

Xylazine is increasingly reported in street drugs and fatal overdoses in the United States (US), often in combination with synthetic opioids, yet state-level xylazine data are limited, hampering local public health responses. The present study analyzed 2018-2022 state-level data from the National Forensic Laboratory Information System (xylazine-positive reports of seized drugs analyzed by forensic laboratories), the Centers for Disease Control and Prevention (population estimates, synthetic opioid overdose mortality rates), and individual states' medical examiner/public health agency reports (numbers of xylazine-involved overdose deaths). An ordinary least squares regression model predicted state-level synthetic opioid overdose mortality rates by xylazine seizure report rates, adjusting for US Census Region. In 2018, relatively low rates of xylazine seizure reports were observed, with 21 states reporting zero xylazine seizures. In 2022, only three states reported zero xylazine seizures, and the highest xylazine seizure report rates (per 100,000 residents) were observed in New Jersey (30.4), Rhode Island (22.7), Maryland (18.9), Virginia (15.5), New Hampshire (13.0), and Ohio (10.9). Data on 2019-2022 xylazine-involved overdose deaths were available for 21 states/DC (60 state-years), with the highest 2022 xylazine-involved overdose death rates (per 100,000 residents) in Vermont (10.5) and Connecticut (9.8). Finally, in 2021, at the state level, each additional reported xylazine seizure per 100,000 residents was associated with a 2% higher synthetic opioid overdose mortality rate (b=0.02, robust standard error=0.01; p=0.049). Overall, study results emphasize xylazine's increasing involvement in US law enforcement drug seizure reports and overdose deaths, primarily in the East, yet also extending across the country.

County-level predictors of US drug overdose mortality: A systematic review

BACKGROUND

This systematic review summarized published literature on county-level predictors of drug overdose mortality in the United States (US).

METHODS

Peer-reviewed studies and doctoral dissertations published in English between 1990 and July 19, 2022 were identified from PubMed, Web of Science, ProQuest Dissertations & Theses, PsycINFO, CINAHL, and EconLit. Eligible studies examined at least one county-level predictor of drug overdose mortality in US counties. Two reviewers independently completed screening, quality assessment (with an adapted National Institutes of Health Quality Assessment Tool), and data extraction. Results were qualitatively summarized and grouped by predictor categories.

RESULTS

Of 56 studies included, 42.9% were subnational, and 53.6% were limited to opioid overdose. In multiple studies, measures related to opioid prescribing, illness/disability, economic distress, mining employment, incarceration, family distress, and single-parent families were positively associated with drug overdose mortality outcomes, while measures related to cannabis dispensaries, substance use treatment, social capital, and family households were negatively associated with drug overdose mortality outcomes. Both positive and negative associations were documented for smoking, uninsurance, healthcare professional shortage status, physicians per capita, unemployment, income, poverty, educational attainment, racial composition, and rurality. Findings within studies also differed by subpopulation (by race/ethnicity, gender, age, or rurality) and the type of drugs involved in overdose.

CONCLUSIONS

The findings of this review provide relatively mixed evidence regarding many county-level predictors of overdose mortality, several of which also vary between subpopulations, supporting the importance of additional research to elucidate pathways through which the county context may shape risk of fatal overdose.

Sociodemographic and geographic disparities in excess fatal drug overdoses during the COVID-19 pandemic in California: A population-based study

Background

The coronavirus disease 2019 (COVID-19) pandemic is co-occurring with a drug addiction and overdose crisis.

Methods

We fit overdispersed Poisson models, accounting for seasonality and secular trends, to estimate the excess fatal drug overdoses (i.e., deaths greater than expected), using data on all deaths in California from 2016 to 2020.

Findings

Between January 5, 2020 and December 26, 2020, there were 8605 fatal drug overdoses—a 44% increase over the same period one year prior. We estimated 2084 (95% CI: 1925 to 2243) fatal drug overdoses were excess deaths, representing 5·28 (4·88 to 5·68) excess fatal drug overdoses per 100,000 population. Excess fatal drug overdoses were driven by opioids (4·48 [95% CI: 4·18 to 4·77] per 100,000), especially synthetic opioids (2·85 [95% CI: 2·56 to 3·13] per 100,000). The non-Hispanic Black and Other non-Hispanic populations were disproportionately affected with 10·1 (95% CI: 7·6 to 12·5) and 13·26 (95% CI: 11·0 to 15·5) excess fatal drug overdoses per 100,000 population, respectively, compared to 5·99 (95% CI: 5.2 to 6.8) per 100,000 population in the non-Hispanic white population. There was a steep, nonlinear educational gradient with the highest rate among those with only a high school degree. There was a strong spatial patterning with the highest levels of excess mortality in the southernmost region and consistently lower levels at progressively more northern latitudes (7·73 vs 1·96 per 100,000).

Interpretation

Fatal drug overdoses disproportionately increased in 2020 among structurally marginalized populations and showed a strong geographic gradient. Local, tailored public health interventions are urgently needed to reduce growing inequities in overdose deaths.

Funding

US National Institutes of Health and Department of Veterans Affairs.

Individual and County-Level Disparities in Drug and Opioid Overdose Mortality for Hispanic Men in Massachusetts and the Northeast United States

BACKGROUND

This study aimed to identify individual- and county-level inequalities that may underlie disparities in drug overdose mortality for Hispanic men in Massachusetts and the broader Northeast region.

METHODS

The study first used data from the State Unintentional Drug Overdose Reporting System to compare the 635 Hispanic and 3593 Non-Hispanic (NH) White men who died of unintentional/undetermined opioid-related overdoses in Massachusetts in 2016-2018. Next, the study used 2015-2019 data from the Multiple Cause of Death online platform to: a) compare rates of drug overdose mortality in Hispanic versus NH White men in 54 counties in the Northeast United States; and b) examine associations with inequalities in poverty, educational attainment, unemployment, and uninsurance (from 2015-2019 American Community Survey data).

RESULTS

At the individual level, in Massachusetts, Hispanic and NH White men who died of opioid-related overdose differed in terms of educational attainment, birthplace, urbanicity, substance use disorder treatment history, and specific drugs involved in death. At the county level, in the Northeast region, each one-standard deviation increase in the ratio of the Hispanic to NH White poverty rate was associated with a 27% increase in the ratio of Hispanic to NH White male overdose mortality; each one-standard deviation increase in the ratio of the Hispanic to NH White unemployment rate was associated with a 43% increase in the ratio of Hispanic to NH White male overdose mortality.

CONCLUSIONS

Findings underscore the importance of equitable interventions and efforts to address inequalities in social determinants of health for Hispanic populations in the Northeast.

Michigan system for opioid overdose surveillance

Community rapid response may reduce opioid overdose harms, but is hindered by the lack of timely data. To address this need, we created and evaluated the Michigan system for opioid overdose surveillance (SOS). SOS integrates suspected fatal overdose data from Medical Examiners (MEs), and suspected non-fatal overdoses (proxied by naloxone administration) from the Michigan Emergency Medical Services (EMS) into a web-based dashboard that was developed with stakeholder feedback. Authorised stakeholders can view approximate incident locations and automated spatiotemporal data summaries, while the general public can view county-level summaries. Following Centers for Disease Control and Prevention (CDC) surveillance system evaluation guidelines, we assessed simplicity, flexibility, data quality, acceptability, sensitivity, positive value positive (PVP), representativeness, timeliness and stability of SOS. Data are usually integrated into SOS 1-day postincident, and the interface is updated weekly for debugging and new feature addition, suggesting high timeliness, stability and flexibility. Regarding representativeness, SOS data cover 100% of EMS-based naloxone adminstrations in Michigan, and receives suspected fatal overdoses from MEs covering 79.1% of Michigan's population, but misses those receiving naloxone from non-EMS. PVP of the suspected fatal overdose indicator is nearly 80% across MEs. Because SOS uses pre-existing data, added burden on MEs/EMS is minimal, leading to high acceptability; there are over 300 authorised SOS stakeholders (~6 new registrations/week) as of this writing, suggesting high user acceptability. Using a collaborative, cross-sector approach we created a timely opioid overdose surveillance system that is flexible, acceptable, and is reasonably accurate and complete. Lessons learnt can aid other jurisdictions in creating analogous systems.

Growing racial/ethnic disparities in buprenorphine distribution in the United States, 2007-2017

OBJECTIVE

To assess whether per capita buprenorphine distribution varies by regional racial/ethnic composition, Medicaid expansion status, and time period.

METHODS

Our unit of analysis -- three-digit ZIP codes ("ZIP3s") -- was classified into quintiles based on percentage of White residents. A weighted linear regression model of buprenorphine distribution -- including White resident quintile, waivered prescriber rate, overdose rate, sociodemographic factors, and year fixed effects -- was estimated using national buprenorphine distribution data from 2007 to 2017. We report predictive margins of the buprenorphine distribution rate by quintile, as well as average marginal effects of waivered prescriber rate on buprenorphine distribution rate for each quintile. Analyses were stratified by Medicaid expansion status and time period (2007-2010, 2011-2014, 2015-2017).

RESULTS

Buprenorphine distribution increased nationally during 2007-2017, yet growth was disproportionately greater for ZIP3s with higher percentages of White residents. Medicaid expansion states exhibited significant differences in buprenorphine distribution across ZIP3 quintiles during 2007-2010, the magnitude of which increased across time periods. Non-expansion states exhibited significant quintile differences during 2011-2014 and 2015-2017. The average marginal effect of increasing the waivered prescriber rate on the distribution rate was consistently smaller in ZIP3s with lower percentages of White residents, particularly in expansion states.

CONCLUSIONS

We find ecological evidence consistent with racial/ethnic disparities in buprenorphine distribution. Our finding that increasing the waivered prescriber rate had differential effects by ZIP3 racial/ethnic composition suggest that broad initiatives to increase the number of waivered prescribers are likely insufficient to achieve equitable buprenorphine access. Rather, targeted and tailored policy efforts are warranted.

Methodological Challenges and Proposed Solutions for Evaluating Opioid Policy Effectiveness

Opioid-related mortality increased by nearly 400% between 2000 and 2018. In response, federal, state, and local governments have enacted a heterogeneous collection of opioid-related policies in an effort to reverse the opioid crisis, producing a policy landscape that is both complex and dynamic. Correspondingly, there has been a rise in opioid-policy related evaluation studies, as policymakers and other stakeholders seek to understand which policies are most effective. In this paper, we provide an overview of methodological challenges facing opioid policy researchers when evaluating the effects of opioid policies using observational data, as well as some potential solutions to those challenges. In particular, we discuss the following key challenges: (1) Obtaining high-quality opioid policy data; (2) Appropriately operationalizing and specifying opioid policies; (3) Obtaining high-quality opioid outcome data; (4) Addressing confounding due to systematic differences between policy and non-policy states; (5) Identifying heterogeneous policy effects across states, population subgroups, and time; (6) Disentangling effects of concurrent policies; and (7) Overcoming limited statistical power to detect policy effects afforded by commonly-used methods. We discuss each of these challenges and propose some ways forward to address them. Increasing the methodological rigor of opioid evaluation studies is imperative to identifying and implementing opioid policies that are most effective at reducing opioid-related harms.

Overdose deaths involving psychostimulants with abuse potential, excluding cocaine: State-level differences and the role of opioids

BACKGROUND

Over the course of the past decade, psychostimulants such as methamphetamines have been increasingly reported in overdose deaths in the United States (US). Methamphetamine use has recently risen among individuals who use opioids, yet it is unclear what role the opioid crisis has played in the increase in psychostimulant-involved overdose mortality in states across the US.

METHODS

Mortality data from the Centers for Disease Control and Prevention were used to examine recent state-level changes in overdose deaths involving psychostimulants with abuse potential, excluding cocaine. Psychostimulant-involved overdose mortality rates, changes in rates, and opioid co-involvement were compared by state and plotted on choropleth maps. Ordinary least squares regression analyses were used to test the associations between a state's psychostimulant-involved overdose mortality rate change and several state-level indicators related to the opioid crisis.

RESULTS

From 2015/2016-2017/2018, significant increases in psychostimulant-involved overdose mortality rates were observed in 42 of 47 states with data available. Each of the three state-level indicators examined in the study (opioid prescribing rate in 2012, past-year prevalence of opioid use disorder from 2015-2018, and increase in drug overdose mortality during the earliest stages of the opioid crisis from 1999-2012) was positively associated with the absolute rate change in psychostimulant-involved overdose mortality from 2015/2016-2017/2018.

CONCLUSIONS

Although deaths involving methamphetamine have historically been primarily concentrated in the western US, results of the study reflect the alarming increase in psychostimulant-involved overdose mortality across the nation, especially in some of the states heavily impacted by the opioid crisis.

Drug overdose mortality among stateside Puerto Ricans: Evidence of a health disparity

BACKGROUND

This study compared drug overdose mortality rates in Puerto Rican-heritage and Non-Hispanic (NH) White individuals in the United States (US), examining time trends and recent variation by age, sex, state of residence, and drugs involved in overdose.

METHODS

Death certificate data from the National Center for Health Statistics, as well as American Community Survey population estimates, were used to calculate age-specific and age-adjusted drug overdose mortality rates for Puerto Rican-heritage and NH White residents of the 50 United States or District of Columbia (DC). Rates for 2018 were compared between Puerto Rican-heritage and NH White individuals, overall and by sex, age, state, and specific drug involved in overdose. Joinpoint Regression was used to examine trends in drug overdose mortality rates from 2009 to 2018.

RESULTS

From 2009 to 2018, the age-adjusted drug overdose mortality rate in stateside Puerto Ricans doubled among women (from 6.0 to 12.5 per 100,000) and nearly tripled among men (from 15.3 to 45.2 per 100,000). In 2018, the age-adjusted drug overdose mortality rate was significantly higher in Puerto Rican-heritage than NH White individuals (28.7 vs. 26.2 per 100,000, respectively). The 2018 drug overdose mortality rate was highest among Puerto Rican-heritage men ages 45-54 (104.1 per 100,000).

CONCLUSION

Findings emphasize the necessity of policies, programs, and interventions to mitigate risk of fatal overdose in stateside Puerto Rican communities.