Effects of state opioid prescribing cap laws on providers' opioid prescribing patterns among patients with chronic non-cancer pain

Prior work suggests opioid prescribing cap laws are not associated with changes in opioid prescribing among patients with chronic pain. It is unknown how these effects differ by provider specialty, provider opioid prescribing volume, or patient insurer. This study assessed effects of state opioid prescribing cap laws on opioid prescribing among providers of patients with chronic non-cancer pain, by high volume prescribing, provider specialty, and patient insurer. We identified 224,290 providers of patients with low back pain, fibromyalgia, or headache from the IQVIA administrative database. Using a difference-in-differences approach, we examined impacts of opioid prescribing cap laws implemented between 2016 and 2018 on the annual proportion of a provider's patient panel who received any opioid prescription, as well as on dose and duration of opioid prescriptions. For providers overall, high volume prescribers, all specialties, and patient insurance categories, prescribing cap laws were associated with non-significant changes of <1.0, 1.5, and 3.5 percentage points in the proportion of chronic non-cancer patients receiving any opioid prescription, a prescription with 7 days' supply, or with >50 morphine milligram equivalents (MME)/day, per year, respectively. There were two exceptions with high dose prescribing: prescribing cap laws were associated with a 1.5 percentage point increase in the proportion of high-volume prescribers' patient panel receiving an opioid prescription with ≥50 MME/day, and a 3.0 percentage point decrease in the same measure among surgeons. Among nearly all measured subgroups of providers and patient insurers, opioid prescribing cap laws were not associated with changes in opioid prescribing.