Author ORCID Identifier

https://orcid.org/0000-0001-9096-605X

Date of Award

5-2024

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Public Health

First Advisor

Ruiyan Luo

Second Advisor

Katherine Masyn

Third Advisor

Alana Vivolo-Kantor

Abstract

Background

Drug overdose is one of the leading causes of injury death in the United States. Polysubstance use is the ingestion/injection of more than one substance at the same time, either intentionally or unknowingly, by the person using drugs. Studies indicate that polysubstance use and prescription drug misuse can enhance the potential for negative effects of each drug, leading to unpredictable consequences including nonfatal and fatal overdose. To examine polysubstance use and prescription drug misuse, the following studies will analyze urine drug test results, nonfatal overdoses and fatal overdoses involving multiple substances for trends and characteristics associated with increased risk of polysubstance use.

Methods

Chapter 1 describes background on drug use and overdose along with prevention strategies and data sources for drug use/overdose surveillance. Chapter 1 also discusses limitations to available research, statement of purpose, and implications of research findings.

Chapter 2 analyzes results from Millennium Health Urine Drug Test samples submitted between January 2022-June 2023 to assess positivity rates for combinations of fentanyl, methamphetamine and/or cocaine utilizing multinomial logistic regression.

Chapter 3 uses National Syndromic Surveillance Program (NSSP) data to analyze trends of nonfatal overdose emergency department (ED) visits involving opioids, stimulants, and both opioids and stimulants. Rates during January 2017-December 2022 were assessed using negative binomial regression. Differences in rates were assessed by calculating relative rates with confidence intervals, stratified by demographic characteristics. Overall trends were analyzed by assessing counts and rates over time.

Chapter 4 explores data from the State Unintentional Drug Overdose Reporting System (SUDORS) to analyze trends in fatal overdoses involving combinations of fentanyl and stimulants (i.e., methamphetamine and/or cocaine). Counts during January 2019-June 2022 were assessed using negative binomial regression. Differences in counts across covariates were assessed by calculating log of mean counts with confidence intervals, stratified by demographic characteristics. Overall trends were analyzed by assessing counts and rates over time.

Chapter 5 summarizes findings and discusses policy implications and future directions of research.

Results

Chapter 2 findings: Of specimens analyzed, urine drug tests from patients receiving substance use disorder treatment had greater odds of fentanyl-only, stimulant-only and co-positivity compared to patients receiving primary care.

Chapter 3 findings: Approximately 0.9% of all ED visits analyzed involved both opioids and stimulants. Nonfatal overdose rates varied by demographic characteristics and US Census region. Trend analyses showed increases in overall rates and counts for ED visits involving opioids, stimulants, and both opioids and stimulants during the study period with the 2020 COVID-19 pandemic and seasonality playing key factors.

Chapter 4 findings: Approximately 39% of all overdose deaths analyzed involved both fentanyl and a stimulant. Mean counts of fatal overdose varied by demographic characteristics and US Census region. Counts and percentages of overdose deaths involving both fentanyl and stimulants among all overdose deaths have increased over time.

Conclusion

Each of the three analyses investigated different aspects of the opioid overdose epidemic relating to polysubstance use. The findings from these studies expand upon present research by assessing associations and trends in opioid use, stimulant use and combined opioid and stimulant use. Healthcare providers, policy makers, and others can use the findings from these studies to develop programs, prevention strategies, and policies to reduce prescription drug misuse and overdose in communities. By understanding populations at greatest risk, available resources can be directed to improve health outcomes.

DOI

https://doi.org/10.57709/37369680

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