The Initial Opioid Prescription and Subsequent Use

Opioids have increasingly become a pillar of pain management with prescriptions growing yearly. In parallel, prescription opioids have remained the leading contributor to opioid overdose deaths since 1999, accounting for 15,000+ US deaths in 2015. Although growth in the opioid prescribing has started to ebb, the overall quantity prescribed is still high. And while the people who die of overdose are not typically the ones receiving opioid prescriptions, they may divert excess pills from others who receive opioid prescriptions for medical problems.

In this paper, we estimate the quantity of excess pills (in light of the CDC guideline released in March 2016) prescribed to new opioid users (who receive their first opioid prescriptions after having had no opioid prescription for at least 6 months) enrolled in employer-based commercial insurance, and examine how the initial opioid script affects subsequent opioid use among these people. We focus on the initial opioid script because the CDC guideline is most clear-cut for new users and thus non-compliant prescribing can be more readily identified. Using administrative claims data from anonymous commercial insurers in the United States from January 1, 2013 through June 30, 2016, we construct a longitudinal sample of new opioid users aged 15 years and older (N=1,735,466) followed for 24 months after receiving their initial prescriptions.

We find that almost all (99.7%) new opioid users start with immediate-release opioids, in line with the CDC guideline. However, a nontrivial proportion of new opioid prescriptions do not comply with the guideline in terms of dosage and duration. While CDC recommends using caution when prescribing >= 50 MME/day and avoiding a dosage of >= 90 MME/day for chronic pain, about 25% of new opioid prescriptions exceed 50 MME/day (equivalent to 10 tablets of Vicodin per day), of which 30% exceed 90 MME/day (equivalent to 18 tablets of Vicodin per day). About 84% of new opioid prescriptions give >= 3 days supply, which is more than recommended by CDC to control acute pain. In addition, more than 25% of initial prescriptions give >= 7 days supply, the amount that CDC deems rarely necessary.

Non-compliant daily dosage is most common among specialists (particularly surgeons) and non-physician practitioners, while non-compliant days supply is most common among PCPs. Excess prescribing is least seen among dentists. Patients who receive non-compliant first opioid prescriptions are more likely to be male, with those receiving excess days supply being older and more likely to have chronic pain (as opposed to acute pain).

We then examine how characteristics of the initial prescription affect subsequent opioid use, controlling for prescriber specialty, patients’ history of mental health and substance use disorders, pain condition diagnoses, and other patient characteristics. Preliminary estimates show that about 62% of all new opioid users continue with an opioid in the 24-month period following their first opioids. Stronger, longer initial scripts (in particular, excess prescribing) are associated with higher likelihood of continued use and longer duration of use in the subsequent 24 months.