Purpose: The objective of this study was to identify the trajectories that patients take after initiating long-term opioid therapy (LTOT).
Materials and methods: Using a retrospective cohort design, veterans with chronic non-cancer pain (CNCP) initiating LTOT were identified. Group-based trajectory models were used to identify opioid therapy trajectories based on days of opioid supply (primary outcome) and average daily morphine milligram equivalent dose (AMME; secondary outcome) in each 180-day period following initiation of LTOT.
Results: A total of 438,398 veterans with CNCP initiated LTOT. Nine trajectories were identified: 33.7% with persistent, high days covered, 17.7% with persistent, moderate days covered, 16.6% with slow, persistent days-covered reduction, 2.4% with days-covered reduction followed by increase, 4.6% with delayed days-covered reduction, 4.1% with rapid days-covered reduction, 10.9% with moderate-paced discontinuation, 3.4% with delayed discontinuation, and 6.5% with rapid discontinuation. Patients following discontinuation trajectories were more likely to be younger, persons of color, use more supportive services (eg, physical therapy), and received less opioid days' supply and lower doses prior to initiating LTOT as compared to patients following persistent opioid days-covered trajectories. AMME trajectories were similar to days-covered trajectories.
Conclusion: Among persons initiating LTOT, nine opioid trajectories emerged which can be broadly characterized into three main trajectory groups: persistent opioid therapy (2 trajectories), reductions in opioid therapy (4 trajectories), and discontinuation (3 trajectories). A majority of patients (51.4%) maintained persistent opioid therapy. Further research is needed to assess the risks of opioid-related adverse outcomes among the identified trajectories.
Keywords: chronic non-cancer pain; group-based trajectory models; long-term opioid therapy; opioids; veterans.
© 2021 Hayes et al.