Description of Opioid-involved Hospital Deaths that Do Not Have a Subsequent Autopsy

Background: Surveillance systems rely on death records to monitor the most severe outcome of the opioid epidemic. However, few studies have linked data from hospital systems with death records to determine potential undercount of opioid-involved deaths occurring in hospitals. This study describes characteristics of decedents less likely to have an autopsy following an opioid-involved death in hospitals and estimates the resulting undercount. Methods: A probabilistic data linkage of hospital and medical examiner data involving 4,936 opioid-involved deaths among residents of Cook County, Illinois, US from 2016 to 2019. We included only hospital deaths that met a national case definition and presented with clinical signs of opioid overdose. Results: Decedents had higher odds of not having an autopsy if they were 50+ years, admitted to the hospital (aOR = 3.7: 2.1, 6.5), hospitalized for 4+ days (aOR = 2.2: 1.5, 3.1), and had a comorbid diagnosis of malignant cancer (aOR = 4.3: 1.8, 10.1). However, decedents exposed to heroin and synthetic opioids (aOR = 0.39: 0.28, 0.55), and concurrent exposure to stimulants (aOR = 0.44: 0.31, 0.64) were more likely to have an autopsy). Compared to estimates from the US Centers for Disease Control and Prevention (CDC), we observed undercounts of opioid overdose deaths ranging from 6% to 15%. Conclusions: Surveillance systems may undercount decedents that do not meet the typical profile of those more likely to have an autopsy, particularly older patients with chronic health conditions. Our undercount estimate likely exists in addition to the estimated 20%-40% undercount reported elsewhere. See video abstract at, .