Abstract
Objectives. To assess trends in cocaine overdose deaths and examine the role opioids play in these deaths.
Methods. We used data on drug overdose deaths in the United States from 2000 to 2015 collected in the National Vital Statistics System to calculate annual rates and numbers of cocaine-related overdose deaths overall and deaths both involving and not involving opioids. We assessed statistically significant changes in trends with joinpoint regression.
Results. Rates of cocaine-related overdose deaths increased significantly from 1.26 to 2.50 per 100 000 population from 2000 to 2006, declined to 1.35 in 2010, and increased to 2.13 in 2015. Cocaine-related overdose deaths involving opioids increased from 0.37 to 0.91 from 2000 to 2006, declined to 0.57 in 2010, and then increased to 1.36 in 2015. Cocaine-related overdose deaths not involving opioids increased from 0.89 to 1.59 from 2000 to 2006 and then declined to 0.78 in 2015.
Conclusions. Opioids, primarily heroin and synthetic opioids, have been driving the recent increase in cocaine-related overdose deaths. This corresponds to the growing supply and use of heroin and illicitly manufactured fentanyl in the United States.
Individuals with co-occurring cocaine and opioid use disorders have more severe drug use and legal problems and poorer substance use treatment outcomes compared with individuals with either substance use disorder alone.1,2 Research shows that heroin use among people using cocaine increased significantly between 2008 to 2010 and 2011 to 2013 and that cocaine use disorder was a significant risk factor for both heroin and prescription opioid use disorder.3,4
Since 2010, overdose deaths involving heroin and, more recently, synthetic opioids (e.g., illicitly manufactured fentanyl) have increased.5 A recent investigation of fentanyl overdose deaths in Florida and Ohio found that cocaine use was commonly involved in these deaths.6 An examination of how the increase in opioid use among cocaine users has affected cocaine overdose deaths in the United States is lacking. We examined drug overdose death data to assess this relationship and inform public health overdose prevention and treatment strategies.
METHODS
Data were from the National Vital Statistics System multiple cause-of-death mortality files. Drug overdose deaths were those assigned an International Classification of Diseases, 10th Revision,7 underlying cause-of-death code: X40–44 (unintentional), X60–64 (intentional self-harm), X85 (homicide), and Y10–Y14 (undetermined intent). Cocaine-related overdose deaths were those assigned code T40.5; overdose deaths involving natural or semisynthetic opioids were those assigned T40.2; methadone, T40.3; heroin, T40.1; and synthetic opioids (not including methadone), T40.4.
For cocaine-related overdose deaths, we calculated the rate and number of deaths by year for 2000 through 2015 overall and by deaths involving natural or semisynthetic opioids, methadone, heroin, or synthetic opioids (termed any opioid deaths); deaths involving heroin or synthetic opioids; and deaths not involving opioids. We also calculated, by year, percentages of cocaine-related overdose deaths involving any opioid and the percentages of these deaths involving heroin or synthetic opioids. Emerging research suggests that the increase in synthetic opioid–related deaths is predominantly the result of increased exposure to illicitly manufactured fentanyl, and the population of individuals using fentanyl largely resembles those using heroin in the United States.8,9 For these reasons, we examined deaths involving heroin or synthetic opioids as a single group. All rates were calculated per 100 000 population and were age-adjusted by applying age-specific death rates to the 2000 US standard population age distribution. Significance testing was based on the z test at a significance level of .05.
We used Joinpoint Regression, version 4.2.0.2 (National Cancer Institute, Bethesda, MD), to examine changes in trends between 2000 and 2015. Joinpoint regression models annual trend data by fitting an exponential curve (i.e., no annual percentage change), then adding joinpoints, 1 at a time, and performing a Monte Carlo permutation test to determine the optimal number of joinpoints. In the final model, each joinpoint indicates a statistically significant increase or decrease in trend, and each of these trends is described by the annual percentage change between each joinpoint. A P value of less than .05 was considered statistically significant.
RESULTS
Cocaine-related overdose death rates increased significantly from 1.26 to 2.50 per 100 000 population from 2000 (n = 3544) to 2006 (n = 7448; Table 1). After 2006, the death rate declined to 1.35 per 100 000 (n = 4183) in 2010 before rising to 2.13 per 100 000 (n = 6784) in 2015. The rate of cocaine-related overdose death not involving opioids increased from 0.89 to 1.59 per 100 000 from 2000 (n = 2501) to 2006 (n = 4731) and then declined to 0.78 per 100 000 (n = 2513) in 2015.
TABLE 1—
Number and Rate of Cocaine-Related Overdose Deaths Overall and by Type of Opioid Involvement: National Vital Statistics System, United States, 2000–2015
| Cocaine-Related Overdose Deaths |
Cocaine-Related Overdose Deaths, No Opioida Involved |
Cocaine-Related Overdose Deaths, Any Opioida Involved |
Cocaine-Related Overdose Deaths, Heroin or Synthetic Opioidb Involved |
|||||
| Year | No. (SE) | Rate (SE) | No. (SE) | Rate (SE) | No. (SE) | Rate (SE) | No. (SE) | Rate (SE) |
| 2000 | 3544 (59.5) | 1.26 (0.02) | 2501 (50.0) | 0.89 (0.02) | 1043 (32.3) | 0.37 (0.01) | 576 (24.0) | 0.20 (0.01) |
| 2001 | 3833 (61.9) | 1.35 (0.02) | 2698 (51.9) | 0.95 (0.02) | 1135 (33.7) | 0.40 (0.01) | 596 (24.4) | 0.21 (0.01) |
| 2002 | 4599 (67.8) | 1.60 (0.02) | 3116 (55.8) | 1.08 (0.02) | 1483 (38.5) | 0.52 (0.01) | 715 (26.7) | 0.25 (0.01) |
| 2003 | 5199 (72.1) | 1.79 (0.02) | 3584 (59.9) | 1.24 (0.02) | 1615 (40.2) | 0.56 (0.01) | 730 (27.0) | 0.25 (0.01) |
| 2004 | 5443 (73.8) | 1.86 (0.03) | 3643 (60.4) | 1.24 (0.02) | 1800 (42.4) | 0.61 (0.01) | 690 (26.3) | 0.24 (0.01) |
| 2005 | 6208 (78.8) | 2.10 (0.03) | 4092 (64.0) | 1.38 (0.02) | 2116 (46.0) | 0.72 (0.02) | 851 (29.2) | 0.29 (0.01) |
| 2006 | 7448 (86.3)c | 2.50 (0.03)c | 4731 (68.8)c | 1.59 (0.02)c | 2717 (52.1)c | 0.91 (0.02)c | 1129 (33.6)c | 0.38 (0.01)c |
| 2007 | 6512 (80.7) | 2.16 (0.03) | 4048 (63.6) | 1.34 (0.02) | 2464 (49.6) | 0.82 (0.02) | 907 (30.1) | 0.30 (0.01) |
| 2008 | 5129 (71.6) | 1.69 (0.02) | 2962 (54.4) | 0.97 (0.02) | 2167 (46.6) | 0.71 (0.02) | 918 (30.3) | 0.30 (0.01) |
| 2009 | 4350 (66.0) | 1.42 (0.02) | 2558 (50.6)c | 0.84 (0.02)c | 1792 (42.3) | 0.58 (0.01) | 822 (28.7) | 0.27 (0.01) |
| 2010 | 4183 (64.7)c | 1.35 (0.02)c | 2433 (49.3) | 0.79 (0.02) | 1750 (41.8)c | 0.57 (0.01)c | 727 (27.0)c | 0.24 (0.01)c |
| 2011 | 4681 (68.4) | 1.50 (0.02) | 2554 (50.5) | 0.82 (0.02) | 2127 (46.1) | 0.68 (0.01) | 1043 (32.3) | 0.33 (0.01) |
| 2012 | 4404 (66.4) | 1.40 (0.02) | 2303 (48.0) | 0.73 (0.02) | 2101 (45.8) | 0.67 (0.01) | 1224 (35.0) | 0.39 (0.01) |
| 2013 | 4944 (70.3) | 1.56 (0.02) | 2404 (49.0) | 0.76 (0.02) | 2540 (50.4) | 0.80 (0.02) | 1713 (41.4) | 0.54 (0.01) |
| 2014 | 5415 (73.6) | 1.70 (0.02) | 2212 (47.0) | 0.69 (0.01) | 3203 (56.6) | 1.00 (0.02) | 2414 (49.1) | 0.76 (0.02) |
| 2015 | 6784 (82.4) | 2.13 (0.03) | 2513 (50.1) | 0.78 (0.02) | 4271 (65.4) | 1.36 (0.02) | 3481 (59.0) | 1.11 (0.02) |
Note. Rates were calculated per 100 000 population and were age-adjusted by applying age-specific death rates to the 2000 US standard population age distribution.
Defined as any natural or semisynthetic opioid, methadone, heroin, or synthetic opioid.
Does not include the synthetic opioid methadone.
Joinpoint (inflection) identified in this year in the joinpoint regression analysis, P < .05.
Cocaine-related overdose death rates involving any opioid increased from 0.37 to 0.91 per 100 000 from 2000 (n = 1043) to 2006 (n = 2717). After 2006, the death rate declined to 0.57 per 100 000 (n = 1750) in 2010 before rising to 1.36 per 100 000 (n = 4271) in 2015. The rate of cocaine-related overdose deaths involving heroin or synthetic opioids increased from 0.20 to 0.38 per 100 000 from 2000 (n = 576) to 2006 (n = 1129) and then declined to 0.24 per 100 000 (n = 727) in 2010 before increasing to 1.11 per 100 000 (n = 3481) in 2015.
The percentage of cocaine-related overdose deaths involving any opioid increased from 29.4% in 2000 to 63.0% in 2015 (Table A, available as a supplement to the online version of this article at http://www.ajph.org). Among these deaths, heroin or synthetic opioids have been increasingly contributing to these deaths since 2010, contributing to 81.5% of these deaths in 2015.
Joinpoint regression estimates are indicated in Table 1 and displayed in Figure A (available as a supplement to the online version of this article at http://www.ajph.org). Between 2000 and 2006, cocaine-related overdose deaths not involving opioids increased, on average, 11.3% per year. This was followed by persistent declines of 19.0% per year between 2006 and 2009 and a 1.0% decrease per year between 2009 and 2015. Cocaine-related overdose deaths involving any opioid increased 17.6% per year between 2000 and 2006, declined 11.2% per year between 2006 and 2010, and increased 19.3% per year between 2010 and 2015. The number of cocaine-related overdose deaths involving heroin or synthetic opioids increased 11.1% per year between 2000 and 2006, declined 8.4% per year between 2006 and 2010, and increased 36.1% per year between 2010 and 2015.
DISCUSSION
Cocaine-related overdose deaths increased significantly between 2000 and 2006. Between 2006 and 2010, consistent with a reduction in supply and an increase in street prices,10 cocaine-related overdose deaths declined. However, after 2010, despite continued declines in cocaine use,11 overdose deaths involving cocaine increased more than 60%. This increase in deaths occurred when opioids, primarily heroin or synthetic opioids, also were involved and corresponds to the growing supply and use of heroin and illicitly manufactured fentanyl in the United States.3,6,9
The public health and public safety response to increasing cocaine-related overdose deaths should be comprehensive and informed by the role opioids play. This is particularly important given the rapid increase in cocaine-related deaths involving synthetic opioids such as fentanyl and its highly potent analogs.
Use of opioids can lead to sudden respiratory depression. This is particularly true for fentanyl and its analogs because of their potency and rapid onset of action. In the absence of recent, regular opioid use, someone using cocaine and fentanyl (knowingly or unknowingly) would be highly susceptible to opioid-induced respiratory depression and subsequent overdose. Reports indicate that this is occurring.12,13 Having naloxone readily available—even among people primarily using cocaine—is a key strategy for reducing overdose deaths. Additionally, because fentanyl (and its analogs) may necessitate multiple doses to reverse an overdose, at-risk individuals and first responders should be equipped with adequate naloxone supplies.
Expanding the provision of medication-assisted treatment with methadone, buprenorphine, or naltrexone in combination with behavioral health services is also crucial to treat co-occurring opioid and cocaine use disorders. For persons who use opioids, regardless of whether they also use cocaine, such medical treatments are essential for reducing substance use and improving health and social outcomes. In addition, the use of contingency management has been found to be particularly useful to reduce cocaine use (for additional references on these interventions, see Table B, available as a supplement to the online version of this article at http://www.ajph.org).
This study had several limitations. Throughout the study period, approximately 20% to 25% of the death certificates did not specify the type of drug(s) involved, and changes in death certificate documentation during the study period could have affected our findings. In addition, although cocaine was specified as a contributing cause of death for these analyses, it may not have been the primary drug involved.
PUBLIC HEALTH IMPLICATIONS
Differentiating cocaine-related deaths from those influenced by opioids has become increasingly difficult. Public health and public safety officials should implement broad public health prevention and treatment strategies as well as supply reduction efforts that attend to use of both drugs simultaneously.
HUMAN PARTICIPANT PROTECTION
Human participant protection was not required because the study was a secondary analysis of de-identified data.
REFERENCES
- 1.Rodríguez-Cintas L, Daigre C, Grau-Lopez L et al. Impulsivity and addiction severity in cocaine and opioid dependent patients. Addict Behav. 2016;58:104–109. doi: 10.1016/j.addbeh.2016.02.029. [DOI] [PubMed] [Google Scholar]
- 2.Kumari S, Manalai P, Leong S, Wooditch A, Malik M, Lawson WB. Factors associated with non-adherence to buprenorphine-naloxone among opioid dependent African-Americans: a retrospective chart review. Am J Addict. 2016;25(2):110–117. doi: 10.1111/ajad.12325. [DOI] [PubMed] [Google Scholar]
- 3.Jones CM, Logan J, Gladden RM, Bohm MK. Vital Signs: demographic and substance use trends among heroin users – United States, 2002-2013. MMWR Morb Mortal Wkly Rep. 2015;64(26):719–725. [PMC free article] [PubMed] [Google Scholar]
- 4.Han B, Compton WM, Jones CM, Cai R. Nonmedical prescription opioid use and use disorders among adults aged 18 through 64 years in the United States, 2003-2013. JAMA. 2015;314(14):1468–1478. doi: 10.1001/jama.2015.11859. [DOI] [PubMed] [Google Scholar]
- 5.Rudd RA, Aleshire N, Zibbell JE, Gladden RM. Increases in drug and opioid overdose deaths – United States, 2000-2014. MMWR Morb Mortal Wkly Rep. 2016;64(50-51):1378–1382. doi: 10.15585/mmwr.mm6450a3. [DOI] [PubMed] [Google Scholar]
- 6.Peterson AB, Gladden RM, Delcher C et al. Increases in fentanyl-related overdose deaths – Florida and Ohio, 2013-2015. MMWR Morb Mortal Wkly Rep. 2016;65(33):844–849. doi: 10.15585/mmwr.mm6533a3. [DOI] [PubMed] [Google Scholar]
- 7.International Classification of Diseases, 10th Revision. Geneva, Switzerland: World Health Organization; 1992. [Google Scholar]
- 8.Spies E, Peterson A, Garcia-Williams A Undetermined risk factors for fentanyl-related overdose deaths – Ohio, 2015 (EpiAid 2016-003) Trip Report – Epi2. Available at: http://www.healthy.ohio.gov/∼/media/HealthyOhio/ASSETS/Files/injury%20prevention/Ohio%20PDO%20EpiAid%20Trip%20Report_Final%20Draft_3_18_2016.pdf. Accessed October 17, 2016. [DOI] [PubMed]
- 9.Gladden RM, Martinez P, Seth P. Fentanyl law enforcement submissions and increases in synthetic opioid-involved overdose deaths – 27 states, 2013-2014. MMWR Morb Mortal Wkly Rep. 2016;65(33):837–843. doi: 10.15585/mmwr.mm6533a2. [DOI] [PubMed] [Google Scholar]
- 10.White House Office of National Drug Control Policy. What America’s users spend on illegal drugs: 2000-2010. February 2014. Available at: https://www.whitehouse.gov/sites/default/files/ondcp/policy-and-research/wausid_results_report.pdf. Accessed October 17, 2016.
- 11.Substance Abuse and Mental Health Services Administration. Results From the 2014 National Survey on Drug Use and Health: Detailed Tables. 2015. Available at: http://www.samhsa.gov/data/sites/default/files/NSDUH-DetTabs2014/NSDUH-DetTabs2014.htm#tab7-3b. Accessed October 19, 2016. [PubMed]
- 12.Amlani A, McKee G, Khamis N, Raghukumar G, Tsang E, Buxton JA. Why the FUSS (Fentanyl Urine Screen Study)? A cross-sectional survey to characterize an emerging threat to people who use drugs in British Columbia, Canada. Harm Reduct J. 2015;12:54. doi: 10.1186/s12954-015-0088-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Klar SA, Brodkin E, Gibson E et al. Notes from the Field: Furanyl-fentanyl overdose events caused by smoking contaminated crack cocaine – British Columbia, Canada, July 15-18, 2016. MMWR Morb Mortal Wkly Rep. 2016;65(37):1015–1016. doi: 10.15585/mmwr.mm6537a6. [DOI] [PubMed] [Google Scholar]