A recent cohort study revealed that only 34% of attempts at low-dose buprenorphine initiation were successful among patients with opioid use disorder using fentanyl.
Conducted at two substance use disorder treatment clinics in San Francisco, California, between May 2021 and November 2022, and published in JAMA Network Open, the study evaluated the efficacy of two outpatient low-dose buprenorphine initiation (LDI) protocols.
The researchers analyzed 175 LDI attempts involving 126 adults who self-reported daily fentanyl use. The participants initiated either a 4-day or 7-day LDI protocol. Success was defined as completing the initiation and picking up a refill maintenance prescription. The researchers found no statistically significant difference in the success rates between the two protocols. The 4-day protocol had a 38% success rate and the 7-day protocol had a 28% success rate.
The retention rates for buprenorphine at 28 days were low—21% for the 4-day protocol and 18% for the 7-day protocol. Repeated initiation attempts were linked to a diminished rate of success. Compared with first attempts, second attempts had an adjusted odds ratio (OR) of 0.30 (95% confidence interval [CI] = 0.14–0.66), whereas third or subsequent attempts had an adjusted OR of 0.22 (95% CI = 0.09–0.53).
The study adjusted for multiple factors, including age, gender identity, race and ethnicity, and housing status. The participants' median age was 35 years, and 71% identified as male. Racial demographics included 21% Black, 16% Latinx, and 52% White participants.
Buprenorphine retention was assessed using Kaplan-Meier survival curves and Cox proportional hazards regression models, but no statistically significant differences in retention rates between the two protocols were detected.
"LDI has become an increasingly common strategy for initiating buprenorphine treatment among a cohort of publicly insured or uninsured [patients] using fentanyl. However, successful LDI completion in outpatient settings remains low, and successive attempts at LDI yield diminishing returns," wrote lead study author Leslie W. Suen, MD, of the Division of General Internal Medicine at San Francisco General Hospital in the Department of Medicine at the University of California, San Francisco, and colleagues.
The findings provided crucial insights into the complexities of buprenorphine treatment in the fentanyl era and pointed to the necessity for future studies to explore more effective approaches to increase buprenorphine uptake and retention.
Full disclosures are available in the study.
