Understanding the relationship between economic conditions and opioid-related adverse events is vital to tackling the opioid crisis.4 We examined this relationship using US data available for both variables from 2017 to 2019. These years were chosen as opioid data was not explicitly available prior to 2017 (i.e., death rates were combined with other substances, including alcohol) and we did not include data after 2019 as to not confound our results with the COVID-19 pandemic that preliminary data suggests negatively impacted the opioid crisis.4,7
Our data suggested that opioid overdose death rates were spatially clustered across the US. Most noticeably, states at the intersection of the Midwest, Northeast and Southeast were highly positively correlated with each other in 2017 and 2019. During these years, trends with respect to the location and degree of clustering of opioid overdose deaths were similar and demonstrated by patterns found in the hotspot maps and the larger calculated Moran’s global I values. This is not surprising given these areas have similar economic flux and taxation patterns.23,24 In contrast, there was an overall lack of clustering in 2018, as indicated by the smaller Moran’s global I value for 2018. One possibility for this may be the various initiatives brought on by the 2017 Tax Cuts and Jobs Act, which aimed to increase employment across the US but was inconsistently taken up by various jurisdictions in 2018.23,24 By 2019, it was predicted that most neighbouring states had similar uptake of the Act.23,24 Our analyses suggested that spatial clustering was unlikely due to chance alone.
We reported that a 1% increase in unemployment was associated with a 7% and 5% increase in opioid overdose deaths in 2017 and 2019, respectively. These values are higher than those reported by the National Bureau of Economic Research, which concluded that as unemployment increased by 1%, opioid overdose deaths increased by 3.6% between 2003 to 2014.25 This is not surprising given that other countries such as Australia and Canada have reported a significant spike in opioid overdose deaths starting in 2016.25 This was unlike 2018, where unemployment appeared to confer a protective effect on opioid overdose deaths. Some reasons for this include the dramatic uptake of opioid abuse-deterrent formulations (ADF) by prescribers seen mid-2017 and 2018, but not subsequent years, and the increase in drug take-back programs which were heavily funded by the Drug Enforcement Administration (DEA) in 2018 compared to other years.27 The higher unemployment rates in 2017 and 2019 may also be attributable to Hurricanes Harvey, Irma and Dorian, major hurricanes documented to significantly affect nonfarm employment, namely hospitality and transportation.28,29,30
Ultimately, it should be noted that 2018 did not follow similar patterns seen in 2017 and 2019. This could be due to the inability to consider factors such as increased initiatives to manage the opioid crisis and changes in opioid prescribing policies, which were largely taken up in 2018 compared to other years.23,24,26 Given these scattered and inconsistent results, it is difficult to precisely summarize the relationship between unemployment and opioid overdose deaths across the three years.
Strengths of the study include the use of robust and complete datasets, with no missing data. The data was obtained from comprehensive data sources, which collect surveillance population data. Our time period did not encompass the COVID-19 pandemic as more information is required on how this has affected unemployment and opioid overdose deaths in the US for meaningful analyses to be conducted. Some limitations exist for this study. We only studied three years as we chose to exclude data prior to 2017 due to possible misclassification of opioid overdose deaths, which were grouped together as opioid-related harms by the data source. For example, prior to 2014, deaths due to opioid overdoses were grouped in a general category with other substance use deaths. Our analyses may be strengthened and show a more accurate time-trend if more years were included. Furthermore, we did not adjust for potential confounders such as age, gender and race/ethnicity, nor did we stratify by variables such as the implicated opioid or laws surrounding opioid misuse.
Thus far, strategies aimed at restricting opioid supply and influencing prescriber practices have been largely explored to reduce the opioid crisis in the US. Our study suggests that strategies aimed at decreasing unemployment rates in certain jurisdictions should also be explored if we are to successfully tackle this multi-faceted public health issue.