For someone who has not heard of it before, can you explain what a hypoxic-ischemic brain injury is and how it may impact a person?
HIBI stands for hypoxic-ischemic brain injury. In the case of an overdose, people may stop breathing or breathe very slowly, which can lead to the brain not getting enough oxygen. When this happens, it can damage the cells of the brain and result in a spectrum of injuries. Mild injuries may involve someone struggling to speak or think. More severe cases can result in a person’s brain no longer functioning and a person never regaining consciousness.
What inspired you to conduct this research?
The majority of clinical and public health efforts around individuals with opioid use disorder has been focused on trying to reduce fatal overdoses — and rightfully so. We should be investing heavily in that. At the same time, I think comparatively little attention has been paid to the health consequences suffered by people who survive overdoses.
Because public health and harm reduction efforts have done an increasingly good job at keeping people alive, there is a growth in the prevalence of people who have survived opioid overdoses. There will continue to be more survivors, who will age, and I think we’re just starting to grapple with health issues among survivors. Part of our motivation for this research was understanding how sick these survivors are, because we know HIBI is occurring among this population.
How did you go about getting these national estimates?
We used data from the National Inpatient Sample, which is made available through the federal Agency for Healthcare Research and Quality. The database essentially collects a sample of inpatient hospitalizations from around the country to provide national estimates of any cause of hospitalization. It’s our best resource for looking at trends in hospitalizations. We looked at the most recent data, which was from 2016 to 2021.
Ultimately, you found that out of 441,890 hospital admissions for opioid overdose, HIBI occurred in 22,360 people. Did those findings surprise you?
Seeing that HIBI occurred in approximately 5.1% of hospitalizations for opioid overdose, the percentage was higher than I expected. One in 20 people having HIBI is a lot, given how common opioid overdoses are.
It’s important to note that this is probably an underestimate. There are caveats with this data, because the data are from cases where physicians formally diagnosed and documented that a patient had HIBI. I think more mild cases of HIBI are unlikely to be diagnosed and documented, so those instances are not captured.
Of those with HIBI, the data showed there was high mortality and morbidity. Can you share more about what you found?
Among the hospitalized patients who had HIBI with an overdose, about 62% of those people died in the hospital. It shows that this is a distinctly sick group of opioid overdose patients, because if you look at those without HIBI, the death rate was 1.5% — so HIBI is a big marker of mortality.
We also know this is highly morbid. The median age of these patients was 38 years old, so these are younger people who mostly don’t have preexisting comorbidities. But of the people who survive, 46.8% of them end up being discharged to a skilled nursing facility. About 10% of folks went home with health care needs, and almost another 10% had short-term hospital needs.
We estimate that about 65% of people who survive with HIBI will have a significant need for ongoing medical care when they leave the hospital. Many of these folks will have a high degree of disability.
What were your main takeaways from this research?
The first takeaway is that overdose-associated morbidity, particularly HIBI, is underappreciated. The data shows most people with a HIBI from an opioid overdose die, and of those who survive, many will have significant ongoing health care needs. We know that these are underestimates, and this is our first attempt to elevate the issue. This work supports the need for more attention to the issue.
Second, there is a huge number of people who are going to survive the opioid epidemic, and we need to understand the longer-term health consequences. I think there needs to be more research on post-overdose morbidity among overdose survivors, particularly prospective studies that involve neuropsychological testing over time of people who have had an overdose compared to those who haven’t had an overdose.
Finally, I think this work also re-emphasizes just how important the evidence-based interventions that we have are. People in the general public can help, such as by carrying naloxone or helping loved ones get connected to harm reduction or treatment resources. Reducing unmonitored drug use is also a big push within the harm reduction community. We have good prevention and treatment options — we just need to make sure they are getting to the people who need them.
