High body mass index is prevalent in people with opioid use disorder in Northern England and increases risk of death

Background: Opioids are used clinically for their analgesic and sedative properties but are also misused for their euphoric effects. At high doses opioids can cause respiratory depression and slowed heart rate, which can lead to death.

People who are obese are at higher risk of suffering from other health conditions including obstructive sleep apnoea and cardiac disease due to increased levels of fat deposits – obstructive sleep apnoea when these fat deposits are in the upper respiratory tract where they narrow the airway and restrict breathing, and cardiac disease, such as atherosclerosis and increased blood pressure, when these fat deposits are in the vasculature and narrow blood vessels. Such co-morbidities may increase risk of death from opioid use.

This research examined a population of people from the North of England with opioid use disorder to understand if those who are overweight – as defined by body mass index (BMI) – are at increased risk of death in comparison to people of a healthy weight (BMI (18.50-24.99).

Methods: Data were extracted from Drug & Alcohol Treatment Services at two locations in Northern England (Derbyshire and Teesside) between May 2022 and June 2023 regarding people who were receiving either methadone or buprenorphine opioid agonist therapy (OAT). People who had died whilst engaged with treatment were included where death was due to natural causes and/or accidental drug overdose. Student’s T test used to determine statistical significance (p<0.05) and a binomial linear regression model was used to calculate the adjusted odds ratio and confidence intervals (CIs; at 95%).

Results: 1,807 cases were collected, comprising 1,574 living individuals and 233 decedents. The mean BMI of all individuals (25.75±6.56) was above the threshold considered a healthy weight (≤24.99), with the mean BMI for individuals who had died (26.63±7.87) significantly higher than living individuals (25.61±6.34; p=0.027).

Adjusted odds ratio considering age, gender, OAT type, smoking status, and deprivation decile of usual address indicates a 3.0% increased risk of death for every additional BMI point (aOR 1.030; 95% CIs 1.009 – 1.052). People who were older (aOR 1.021; 95% CIs 1.004 – 1.038), smoked (aOR 3.351; 95% CIs 1.912 – 5.875), and lived in more deprived areas (1 most deprived; 10 least deprived) were more likely to have died (aOR 0.901; 95% CIs 0.841 – 0.966), as were those prescribed methadone (as opposed to buprenorphine; aOR 1.910; 95% CIs 1.134 – 3.217). There was no effect of gender (aOR 1.088; 95% CIs 0.791 – 1.495).

Conclusions: Heavy weight and obesity is prevalent in the studied population of people with opioid use disorder and represents a significant risk factor for death. This is in contravention to the ‘heroin thin’ rhetoric often associated with opioid use. People who use opioids and their healthcare treatment providers should be made aware of this risk and take steps for these people to achieve a healthy weight.