Substance Use
Uncovering Patterns in Overdose Deaths: An Analysis of ‘Spikes’ in Massachusetts Fatal Overdose Data, 2017-2022 Hannah Lee* Hannah Lee Lee Erin Stringfellow Huiru Dong Mohammad Jalali
Research Objective: Two overdose-related trends have emerged in recent years both nationally and in Massachusetts. First, fatal overdoses increasingly involve stimulants like methamphetamine and cocaine. Second, racial disparities are increasing, with the rate of overdoses among Black and/or Hispanic populations now exceeding that of Whites in recent years. There is some speculation that these growing deaths, especially among Black people, are due to contamination of cocaine with fentanyl, which could result from sudden changes in the drug supply. At the same time, first responders often report that periods of calm are followed by a sudden rise in overdoses, which could also point to exogenous supply shocks. In this exploratory analysis, we assessed whether spikes were associated with differences in the drugs involved in deaths or in the race and ethnicity of the people who were dying.
Study Design: To identify spikes in overdose deaths, we used a peak detection algorithm, leveraging z-scores, which is characterized by its robustness, adaptability through lag, threshold-based signaling for significant deviations, and the influence parameter governing the impact of new signals on the calculation of moving mean and standard deviation. Spikes were defined conservatively as deaths exceeding 2.5 rolling standard deviations above the 30-day rolling average. Then, we analyzed the distribution of race and drugs involved on days identified as spikes and those not identified as such. We categorized drugs involved in deaths as: opioid without fentanyl; fentanyl without stimulants; non-cocaine psychostimulants with and without fentanyl; cocaine with and without fentanyl; and both non-cocaine psychostimulants and cocaine.
Population Studied: The study population consisted of 9,990 individuals recorded in Massachusetts’ vital statistics data from 2017-2022 who had experienced a fatal overdose incident. Among these individuals, the median age was 42, 72.2% were males, and 69.2% were White.
Principal Findings: On average, the number of daily deaths in Massachusetts ranged from 4.2 in 2017 to 5.2 in 2022. There was an average of 11.7 spikes in overdose deaths per year. After aggregating the counts of overdose deaths for spike and non-spike days separately throughout the years, we did not find any differences across races (p-value = 0.963) and types of drugs involved (p-value = 0.780) among total overdose deaths in spike days compared to non-spike days. The same results were found when considering each year separately.
Conclusions: Our results suggest that certain days in Massachusetts witnessed a higher number of overdose deaths than anticipated solely based on individual-level variations, potentially attributed to factors influencing people who use drugs as a whole. However, the lack of identified relationships between spike days and drug involvement or the race and ethnicity of the people who died of overdose suggest that significant supply shocks might not be contributing to the growing involvement of stimulants in overdose deaths or to growing racial disparities. We note limitations in our current analysis (primarily, low levels of granularity) that could be leading to false negative conclusions.
Implications for Policy or Practice: Given that the current analysis does not point to an obvious difference in the race and ethnicity of those who are dying on spike days, or in the drugs involved, there may be continuous underlying trends that are more explanatory regarding racial disparities and stimulant involvement. These should be investigated as rigorously as the current narrative around drug contamination.