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SAN DIEGO – Persistence with long-acting naltrexone treatment was associated with significantly reduced detoxification admissions and concurrent engagement in treatment, a retrospective study of veterans found.
The Food and Drug Administration has approved long-acting naltrexone hydrochloride for the treatment of alcohol use disorder (AUD) and opioid use disorder (OUD), but little is known about the patients who initiate and continue this therapy, Grace Chang, MD, MPH, said at the annual meeting and scientific symposium of the American Academy of Addiction Psychiatry. In an effort to evaluate the characteristics associated with long-term naltrexone treatment persistence, Dr. Chang, chief of consultation-liaison psychiatry at the VA Boston Healthcare System, and her associates studied 154 veterans who initiated long-acting naltrexone therapy for AUD or OUD between 2014 and 2015.
Doug Brunk/Frontline Medical News
Dr. Grace Chang
Among those who died in the study year after the index shot, no difference in the average number of long-acting naltrexone injections was observed (5.3 in the OUD group vs. 6.8 in the AUD group, P = .62). There was a long interval between the last known injection of long-acting naltrexone and the date of death (381 days in the OUD group vs. 326 days in the AUD group, P = .67). The cause of death was unknown in 57% of cases, while 21% were from natural causes, and 21% were tied to overdose or self-inflicted injury.
The rates of posttraumatic stress disorder in the OUD and AUD groups were about the same, but the AUD patients had higher rates of mood disorder and anxiety disorder. The AUD patients had higher rates of cardiac disease and pulmonary disease, while the OUD patients had higher rates of musculoskeletal problems. Renal disease was relatively rare in both groups. “The AUD patients started using their drug of choice earlier, but the groups were comparable in being able to attain over 2 years of abstinence at some point,” said Dr. Chang, who is also professor of psychiatry at Harvard Medical School, Boston. “Both groups had about two detoxes in the year prior to the index shot.
“ We were also curious about what other drugs they were using prior to starting naltrexone. The OUD patients used more stimulants, more cocaine, and more sedative hypnotics. Smoking was endemic in both of these groups, as was marijuana use.”
The average interval from the time patients in both groups made the decision to start long-acting naltrexone to the time they received their first shot was about 2 months. “It’s safe to say that no one rushed into this,” Dr. Chang said. “The mean number of injections for the study year was about 5, which was very high, and the range was from 1 to 13, which suggests that some people got a shot every single month. Both of the groups had similar numbers of individual treatment sessions, which was about one. They had almost two residential admissions after the index shot and at least one other appointment with a prescribing psychiatrist.”
On Poisson regression analysis, factors associated with increased medication persistence included percent service connection and number of individual, group, residential, and other treatment modalities attended (P less than .05 for all associations). For each unit increase in the number of individual sessions, the number of long-acting naltrexone shots would go up by 7%, Dr. Chang said. For each unit increase in the number of group sessions, the number of long-acting naltrexone therapy shots would go up by 5%, while for each residential admission session, the number of long-acting naltrexone shots would go up by 14%.
“Keep in mind that our patients had an average of two residential admissions, so the number of shots went up by 28%,” she said. “For the number of other appointments with the addiction psychiatrist, the number of shots went up by 6%.”
Dr. Chang acknowledged certain limitations of the study, including its retrospective design and the relatively small sample size. “What was good to see is that the number of inpatient detox admissions was halved, when comparing the year before and the year after the shot,” she said. “This was highly statistically significant. Concurrent psychosocial treatment is highly important in the treatment persistence with this modality.”
Dr. Chang reported having no relevant financial disclosures.