Lead/Presenter: Brian Lund, COIN - Iowa City
All Authors: Lund BC (Center for Access & Delivery Research and Evaluation. Iowa City VA Healthcare System), Mosher HJ (Center for Access & Delivery Research and Evaluation. Iowa City VA Healthcare System),
Medication assisted treatment (MAT) with buprenorphine is an important tool in addressing the opioid crisis. Service models being implemented in VHA vary from highly distributed approaches encouraging large numbers of prescribers to obtain MAT waivers to manage their own patients with opioid use disorder (OUD), to highly centralized models where patients are instead referred to a small number of high-volume specialty MAT providers. Our objective was to compare treatment retention between models, hypothesizing that patients prescribed buprenorphine by a provider with whom they had an existing therapeutic relationship would have higher rates of retention in treatment.
National VHA outpatient pharmacy data were used to identify buprenorphine initiation from 2011-2017. Treatment retention was assessed by the proportion of days covered (PDC) by buprenorphine over the year following initiation, calculated by the ratio of non-zero cabinet supply days to total observation days. Patients were considered to have a pre-existing relationship with their buprenorphine prescriber if they had at least one prescription from this provider in the year prior to buprenorphine initiation.
Of 23,127 patients initiating buprenorphine, 5,375 (23.2%) received a prior prescription from their buprenorphine prescriber and treatment retention was slightly lower among these individuals (mean PDC = 0.53 vs 0.56; Wilcoxon Z = 6.3; p < 0.001). Patients had similar retention rates regardless of the volume status of their buprenorphine prescriber (1-10 patients: PDC = 0.54; > 100 patients: PDC = 0.57).
Contrary to our hypothesis, we did not find evidence that characteristics associated with distributed care (pre-existing therapeutic relationship or low-volume provider status) were associated with treatment retention in the year following buprenorphine initiation. Rather, retention rates numerically favored characteristics associated with centralized specialty care, but the differences observed are unlikely to be clinically meaningful.
As medical centers across VHA expand and promote an array of MAT service models, it is notable that we did not find a clinically meaningful advantage in treatment retention for distributed care versus centralized specialty models. However, these findings do not speak to potential differences between service models in OUD screening and identification or whether patients choose to initiate buprenorphine MAT.