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Center for Care Delivery and Outcomes Research


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Evaluating Prescription Opioid Changes in Veterans (EPOCH) is a national longitudinal prospective cohort study funded by VA HSR&D (IIR 14-295, IIR 19-083; PI Erin Krebs).  The main objective of EPOCH is to understand effects of changes in opioid prescribing practice (especially opioid dose reduction and discontinuation) on Veterans treated with opioid therapy for chronic pain.  EPOCH is a key study in support of CCDOR’s strategic focus areas of Chronic Pain and Harms Reduction. 

The first EPOCH survey was launched in 2016, shortly after Centers for Disease Control and Prevention (CDC) and VA/Department of Defense opioid prescribing guidelines were published. These guidelines led to a sea change in how opioids for chronic pain were managed, prompting clinicians to initiate opioid tapering to lower doses or discontinuation for patients on long-term opioid therapy.  

EPOCH survey cohort participants are a nationally representative sample of VA patients treated with prescribed opioid analgesics for at least 6 months prior to a 2016 invitation date. A two-stage stratified sampling design was used to identify a representative sample of patients who were invited to participate in a mixed-mode (mail and telephone) survey with annual follow-up.  Of 14,160 patients originally invited, 9253 (65.3%) completed a baseline questionnaire and were enrolled as participants in the survey cohort.1  Follow-up responses have remained fairly strong over time:  7429 (81.9% of eligible) participants at year 1,  6632 (76.7% of eligible) participants at year 2, and 5471 (75.1% of eligible) participants at year 3. Currently, we are cleaning 4-year follow-up survey data and   data collection for the 5-year follow-up survey wave will be completed by April 2022.

In 2019, the EPOCH research team expanded to include a Veteran Engagement Panel (VEP) that includes eight Veterans who have personal experience with chronic pain. The VEP has contributed to development and refinement of follow-up survey questions and development of a supplemental research proposal examining COVID-19 effects on participants. The VEP also collaborated on a research progress update newsletter, which  was mailed to participants prior to the 5-year survey wave.  As the project progresses, we expect the VEP to play an important role in communicating study results to our Veteran patients, caregivers, and the public.

EPOCH has served as a resource for research trainees and cross-COIN collaboration. For example, Dr. Elizabeth Goldsmith (current CCDOR investigator, former HSR&D fellow) used EPOCH data for her epidemiology PhD dissertation and for a published fellowship project.2  Dr. Joseph Frank (Denver COIN investigator) built on study infrastructure to embed an additional telephone survey of experiences related to opioid tapering between the year 1 and 2 follow-up surveys for his HSR&D CDA-2.3 Supplemental funding from HSR&D supported a project with Dr. Amy Bohnert (Ann Arbor COIN investigator) that used EPOCH data to emulate an opioid tapering trial as proposed by the National Academies of Science, Engineering, and Medicine. The team also received supplemental funding from HSR&D to examine associations of pandemic experiences with pain-related function using COVID-19 questions included in the 4-year follow-up survey. 

In coming years, the team anticipates multiple research products and additional collaborations with investigators, especially trainees and fellows, interested in analyzing this rich dataset. 

1Krebs EE, Clothier B, Nugent S, Jensen AC, Martinson BC, Goldsmith ES, Donaldson MT, Frank JW, Rutks I, Noorbaloochi S. The evaluating prescription opioid changes in veterans (EPOCH) study: Design, survey response, and baseline characteristics. PLoS ONE 2020;15(4): e0230751.

2Goldsmith ES, MacLehose RF, Jensen AC, Clothier C, Noorbaloochi S, Martinson BC, Donaldson MT, Krebs EE. 2020. Complementary, Integrative, and Nondrug Therapy Use for Pain Among US Military Veterans on Long-term Opioids. Medical Care 58:S116S124.,_Integrative,_and_Nondrug_Therapy.10.aspx

3Frank JW, Carey E, Nolan C, Hale A, Nugent S, Krebs EE. Association Between Opioid Dose Reduction Against Patients' Wishes and Change in Pain Severity. J Gen Intern Med. 2020 Dec;35(Suppl 3):910-917. doi: 10.1007/s11606-020-06294-z. Epub 2020 Nov 3. PMID: 33145690; PMCID: PMC7728978.
Association Between Opioid Dose Reduction Against Patients’ Wishes and Change in Pain Severity (