The Associations of Kratom (Mitragynine), Opioids, Other Substances, and Sociodemographic Variables to Drug Intoxication-related Mortality.

Introduction: The US age-adjusted drug overdose rate increased by 298%, with fentanyl being the main contributor to drug overdose deaths. The contribution of kratom to drug overdoses or intoxication is seldom reported despite its increasing use and detection among overdose decedents.

Methods: Our cross-sectional study utilized deidentified data from the Florida Department of Law Enforcement, 2020-2021 (N = 30,845). The medical examiners ascertained the exposures of interest (kratom, opioids, and other substances) and the outcome variable of drug intoxication-related mortality (DIRM) through autopsies and toxicology results. DIRM refers to any death from a substance identified as drug toxicity or intoxication. We used regression modeling to examine the association of exposure with DIRM.

Results: Five hundred fifty-one cases were confirmed kratom (mitragynine) exposures. More males died of DIRM (81.5%), primarily White (95.1%) and 35-44 years old (40.5%). Among mitragynine exposures, 484 (87.8%) died of DIRM; 36 decedents (6.5%) used kratom as the sole substance, and 515 (93%) used multiple substances; 437 (79.3%) used at least 1 opioid. The odds of dying of DIRM were 7.6 times higher among those mitragynine exposed compared with non-mitragynine exposed (univariate model) and 5.6 times higher after adjusting for confounders (multivariate model) (adjusted odds ratio = 5.6; 95% confidence interval, 4.1-7; P < 0.001). Opioid use increased the odds of dying of DIRM (adjusted odds ratio = 11.7; 95% confidence interval, 10.9-12.7; P < 0.001).

Conclusion: Our results indicate that dozens of decedents died of kratom (mitragynine) exposures alone, which has safety implications. Co-using opioids with kratom further increased the odds of dying of DIRM, indicating that kratom may not always work as a harm-reduction agent.