Heroin Addicts Face Different Risks of Death during and after Opioid Substitution Therapy
Heroin addicts can significantly improve their quality of life if they undergo opioid substitution therapy (OST), such as inpatient prescribed methadone treatment. In fact, their risk of death is substantially lowered once they commence treatment. However, even though their overall risk of death is lower, patients still face varying risks of death throughout their treatment as they also undergo different risks of relapse. A new study has pinpointed the periods of time in which OST patients have increased risk of death throughout the extent of their treatment.
In a cohort study, researchers at the University of Bristol assessed the effect that OST had on patients at the beginning of treatment, the duration of treatment, and end of treatment. The researchers included 5,577 patients who were diagnosed with a substance use disorder between 1990 and 2005 and were prescribed OST. The majority of the patients were prescribed methadone for their OST, but others were prescribed buprenorphine—an opioid medication similar to methadone. Prior research has extensively shown OST to be an inimitable element of recovery from opioid addiction by safely helping patients become less dependent, less likely to relapse, and more likely to remain abstinent. Furthermore, heroin addicts who undergo OST have improved physical and mental health, and substantially lower risk of hazardous consequences associated with heroin use, such as criminal activity, HIV infection, and other illicit drug use.
Lead researcher Rosie Cornish and her colleagues measured mortality rates among the patients’ during treatment and up to one year after their treatment ended to see if risk of death was higher at the beginning of treatment compared to the time immediately after treatment completion. The researchers also considered such variable as age, gender, comorbidity of disorders, year, and duration of treatment in their measures. Then, the annual mortality rates of the patient population were compared to the annual mortality rates among the general population.
Overall, the researchers found the average annual mortality rate of patients in OST to be 0.7%, approximately 5.3 times higher than that of the general population. For patients off of treatment, the average annual mortality rate was 1.3%, 10.9 times greater than that of the general population. Male opioid users had almost double the risk of death than female opioid users.
In total, 178 of the patients investigated had died during the study (3% of the whole population). When considering the extent of treatment, patients had a 1.7% mortality rate during the first two weeks of treatment—3.1 times higher compared to the remainder of treatment. Between weeks 3–4 of treatment, patients’ risk of death lowered to 2.3 times the rest of treatment, and the rate gradually lowered over the rest of treatment. Among all the patients included in the study, 63 had died while in treatment (35% of all deaths that occurred). In comparison, the researchers found that patients had an increased mortality rate of 4.8% in the first two weeks after completing treatment (9 times higher than the average mortality rate during treatment). During weeks 3–4 off treatment, patients had a mortality rate of 4.3%, and then 0.95% for the remainder of time after treatment (8 and 1.9 times higher that the average mortality rate during treatment, respectively).
The higher risk of death in the time period shortly following treatment could be due to the fact that patients’ tolerance to opioids is drastically reduced after undergoing OST. Therefore, if a patient were to relapse after treatment intended to wean them off opioids, they face a much greater chance of fatal overdose. Additionally, patients may experience a higher risk of death during the first month of OST if their methadone dosages are too high, or if they are still using illicit drugs while taking prescription methadone.
In the UK, OST has increased substantially in recent years. As a result, the number of opioid-related overdose deaths has simultaneously stabilized during this time. The researchers propose that possibly extending the duration of OST could help further reduce patients’ risk of death during these high-risk time frames, but additional research will be needed to confirm this theory. Overall, heroin addicts who underwent OST for 12 months or more reduced their risk of death by more than 85%.
In the meantime, the researchers advise clinicians to educate their OST patients on their varying periods of increased risk to help circumvent the occurrence of drug-related injury or death.
Source: University of Bristol, New study on risk of death during and after opiate substitution therapy, October 27, 2010
