  Introduction: Chronic pain patients are at increased risk of opioid-misuse.
Less is known about the unique risk conferred by each pain-management
treatment, as treatments are typically implemented together, confounding their
independent effects. We estimated the extent to which pain-management
strategies were associated with risk of incident opioid use disorder (OUD) for
those with chronic pain, controlling for baseline demographic and clinical
confounding variables and holding other pain-management treatments at their
observed levels.
  Methods: We used data from two chronic pain subgroups within a cohort of
non-pregnant Medicaid patients aged 35-64 years, 2016-2019, from 25 states: 1)
those with a chronic pain condition co-morbid with physical disability
(N=6,133) or 2) those with chronic pain without disability (N=67,438). We
considered 9 pain-management treatments: prescription opioid i) dose and ii)
duration; iii) number of opioid prescribers; opioid co-prescription with iv)
benzodiazepines, v) muscle relaxants, and vi) gabapentinoids; vii) non-opioid
pain prescription, viii) physical therapy, and ix) other pain treatment
modality. Our outcome was incident OUD.
  Results: Having an opioid and gabapentin co-prescription or an opioid and
benzodiazepine co-prescription was statistically significantly associated with
a 16-46% increased risk of OUD. Opioid dose and duration also were
significantly associated with increased risk of OUD. Physical therapy was
significantly associated with an 11% decreased risk of OUD in the subgroup with
chronic pain but no disability.
  Conclusions: Co-prescription of opioids with either gabapentin or
benzodiazepines may substantially increase risk of OUD. More positively,
physical therapy may be a relatively accessible and safe pain-management
strategy.
