There were 9,784 accidental/undetermined deaths in CT during the study period. Applying the case eligibility criteria, there were 2900 drug-involved accidental/undetermined intoxication deaths in Connecticut from 1997 to 2007, inclusive; 2231 (76.9%) of those were opioid-involved. differentiates the characteristics of opioid-involved from non-opioid involved drug intoxication deaths. Opioid-related accidental/undetermined intoxication deaths tended to occur among men, to affect those under 44 years of age, to also involve alcohol and benzodiazepines, and were less likely to involve cocaine and antidepressants compared to non-opioid intoxication deaths.
Socio-demographics and concomitant substances involved in accidental drug-involved intoxication deaths and in opioid intoxication deaths by opioid overdose pattern, 1997–2007
Toxicological data were available for 2644 decedents (91.2% of all cases) and for 1975 of the opioid-involved deaths (88.5% of 2231), indicating involvement of specific opioid(s). Opioid cases that lacked complete toxicological data were more likely to be male compared to all other opioid-involved deaths (84% versus 75%, p=0.002) but were not distinguishable from the deaths involving heroin on any demographic or geographic variables. Of the 1975 deaths with complete toxicological information, 1769 involved a single opioid, including heroin (n=1195, 67.6%), methadone (n=305, 17.2%), oxycodone (n=140, 7.9%), fentanyl (n=51, 2.9%), hydrocodone (n=43, 2.4%), and propoxyphene (N=28, 1.6%). Of the 206 polyopioid deaths, over 80% involved use of heroin. The most common combination was heroin and one or more prescription opioid (n=116, 56.3%), followed by heroin and methadone (n=47, 22.8%), methadone and one or more other prescription opioid (n=35, 17%), but rarely heroin, methadone, and one or more other prescription opioid in combination (n=10, 4.8%). Among those who died of polyopioid intoxication, the common prescription opioid classes involved were codeine (n=71, 34.5%), followed by oxycodone (n=42, 20.4%), hydrocodone (n=35, 17%) and propoxyphene (n=23, 11.2%). Other drugs commonly found among opioid-involved decedents included cocaine (n=551, 27.9%) and alcohol (n=419, 21.2%), whereas benzodiazepines (n=201, 10.2%) and antidepressants (n=41, 2.1%) were less often detected.
Opioid intoxication deaths occurred throughout the state with no concentrated geographic pattern evident (). Of the 169 CT towns, 148 towns experienced at least one opioid-related death over the 11-year period. However, the pattern differed as a function of the type of opioid. Heroin-only and methadone-only related deaths were more common in cities with populations over 100,000 () whereas death related to other prescription opioids were more common in smaller cities and towns (). Therefore, further analysis was conducted dividing opioid-related deaths into four categories: heroin-only, methadone-only, other prescription opioid-only (hereinafter referred to as prescription opioid-only), and polyopioid.
Figure 1 A–D: Opioid-involved accidental/undetermined deaths per 100,000 population, 1997–2007: residence of decedent aggregated by town. (A) All opioids; (B) Heroin-only; (C) Methadone-only; (D) Deaths dues to single prescription opioids other (more ...)
Bivariate results indicated other notable differences in pattern of opioid deaths (). Heroin-only decedents were more likely male than female. Prescription opioid-only decedents were more likely to be White than non-White, were more likely residents of small towns (population <100,000) rather than cities (population ≥100,000), and tended to die in their hometowns rather than elsewhere. Methadone only victims were more likely to die in their hometown, but their residence tended to be in larger cities. Deaths occurring in a public place were more likely to have involved heroin only or multiple opioids.
The mean number of substances involved across the opioid overdose patterns suggested that most of the heroin-, methadone- and prescription opioid-only deaths involved only one nonopioid substance (e.g, cocaine, alcohol, antidepressants, or benzodiazepines) whereas for the polyopioid overdoses the number of non-opioids exceeded three (e.g., cocaine, alcohol, and benzodiazepines).
3.1 Longitudinal trends and patterns according to time of death
Distinct epidemiologic and longitudinal trends in the opioid accidental intoxication deaths over the 11-year period were also evident in CT ().
Accidental intoxication deaths over time involving specific opioid combinations and not opioid involved
Comparing 1997 to 2007, the absolute number of opioid overdose deaths increased by 44% (from 168 to 242) (). Among the opioid overdose deaths with toxicological data (n=1975 of 2637) there was an increase of 80% over the study period (from 121 to 218). There was no trend in the number of heroin intoxication deaths from 1997 to 2007, which averaged 124.4 per year and ranged from a low of 102 in 1997 to a peak of 160 in 2000. On the other hand, there was a 379% increase in methadone deaths from 14 to 67 (p<0.001). Prescription opioid intoxication deaths increased at an average of 3.9 additional cases per year (p=0.02), rising steadily from 19 in 1997 to 54 in 2000 at a rate of 4% per year (p=0.006) with a statistically significant 28% jump in 2001.
3.1.2 Proportion of deaths due to specific opioids
Although the overall proportion of accidental drug intoxication deaths involving an opioid was unchanged over the study period (linear: 1.87, p=0.17), the relative proportion of the opioids involved in the overdoses changed dramatically (). There was a significant reduction in the proportion of accidental/undetermined deaths involving heroin over time (linearly: 56.43, p<0.001), with greater odds of heroin-only deaths occurring in the years 1997–2003 compared to the years 2004–2007 (). The proportion of methadone-involved deaths significantly increased over time (linearly: 58.09, p<0.001), with the highest proportions of methadone-only deaths occurring 2003 to 2007. Another increasing trend was deaths involving prescription opioids. Starting in 2001, intoxication deaths involving any prescription opioid increased from previous years, a trend which persisted through 2007 (linearly: 25.14, p<0.001). Specific prescription opioids contributing to this phenomenon were fentanyl (linearly: 34.38, p<0.001; 0.6% to 5.3%) and oxycodone (linearly: 38.34, p<0.001; 1.2% to 8.9%). These time trends persisted even after controlling for confounding variables in multivariable regressions (data available upon request).
Heroin-only deaths (N=1195) were significantly more likely to occur on a Friday (15.6%) or a Saturday (21.0%, χ2: 7.6, p=0.006). Those that involved any prescription opioid (N=428) were more likely to occur on a Monday (16.6%, χ2: 17.15, p=0.009) and prescription opioid-only deaths (N=269) tended to occur during the week (Mondays 17.5%, Wednesdays 16.7%, Thursdays 16.0%, χ2 20.25, p<0.001). Opioid-involved deaths wherein cocaine (N=550) or methadone (N=395) was involved tended to occur at uniform rates throughout the week. Finally, alcohol-involved opioid deaths (N=419) were more likely to occur on a Saturday (23.6%, χ2: 16.09, p=0.01). No monthly or quarterly trends were detected.
3.3 Regression analyses
3.3.1 Heroin-only deaths
Compared to other accidental intoxication deaths, the independent risk factors for heroin-only intoxication death were younger age (17–34 years), male gender, and being White. Heroin-only deaths were less likely to occur among people over the age of 45 and tended not to involve concurrent use of antidepressants, benzodiazepines, cocaine, or alcohol (). Use of these other substances was more common among other drug-related intoxication victims. Heroin-only decedents were more likely to die in a public place and to reside in a location with ≥ 100,000 population.
Variables independently associated with heroin-only accidental intoxication deaths and with specific opioid pattern compared to heroin-only deaths among opioid-involved decedents*
3.3.2 Prescription opioids-only
Compared to heroin-only decedents, prescription opioid-only cases were more likely to have resided in small towns/cities of < 100,000 people, to have also used one or more antidepressants, and were less likely to have died in a public place (). Alcohol was as likely to be involved in heroin-only as in prescription opioid-only intoxication deaths. Compared to heroin-only decedents, older age was associated with prescription opioid-only intoxication death (, Adjusted Odds Ratio (AOR) 2.62 aged 55+).
Compared to heroin-only decedents, methadone-only decedents were more likely female (AOR 2.41), to involve benzodiazepine(s) (AOR 3.04), but tended not to die in a public place (AOR 0.56) or to involve alcohol (AOR 0.61) (). Like heroin-only decedents, methadone-only decedents tended to have resided in the large cities of CT.
Polyopioid decedents were more likely than heroin-only decedents to be older than 25 (AOR 0.49 for 17–24 years), female (AOR 2.22), and to have used one or more benzodiazepine (AOR 6.92) (). Polyopioid decedents, like heroin-only decedents, were more likely to reside and die in urban settings and to die in a public place.