Most prescriptions for the drug buprenorphine, used to treat opioid use disorder, are written by a small number of the health care providers, according to a new RAND Corporation study.

Published in the June 1 edition of the Journal of the American Medical Association, the study found that half of all patient-months of buprenorphine treatment during 2016 and 2017 were prescribed by just 4.9% of the physicians and other providers who prescribed the drug during the period.

"These findings have important implications for efforts to increase buprenorphine access," said Dr. Bradley D. Stein, the study's lead author and a senior physician researcher at RAND, a nonprofit research organization. "Our study suggests that targeted efforts to encourage more current prescribers to become high-volume prescribers, and encourage existing high-volume subscribers to safely and effectively treat even more patients, may be a potent way to increase buprenorphine treatment capacity."

Buprenorphine is a drug that helps people with opioid addiction to manage their illness and refrain from illicitly using opioids. Approved for use in 2002, buprenorphine can be prescribed by office-based physicians and other health providers such as nurse practitioners, historically once they have completed an approved course.

Traditional opioid treatment programs commonly require patients to take methadone on-site at a clinic under direct supervision of a health care provider. Such programs typically are located in urban areas, leaving many people in rural areas with little access to treatment.

With an estimated 2 million people across the country affected by opioid use disorder, prior research has shown that greater use of buprenorphine has made medication treatment more accessible to more of those who need help.

In the new study, RAND researchers used IQVIA Prescription data, which captures approximately 90% of all prescriptions filled at retail pharmacies in the U.S., to identify clinicians who prescribed buprenorphine formulations used to treat opioid use disorder at least once between January 2017 and December 2018, and calculated the total months of patient care each clinician provided.

Total patient-months of buprenorphine treatment was driven by a small percentage of high-volume prescribers. Half of all patient-months of buprenorphine treatment during 2017-2018 were prescribed by the most-active 4.9% of prescribers (a total of 2,450 prescribers).

These high-volume prescribers treated an average of 124 patients per month, with primary care physicians (63.6%), psychiatrists (14.3%), pain specialists (8.3%) and addiction specialists (4.4%) representing about 90% of all high-volume prescribers.

The monthly patient caseload for most of those providers was well below the current maximum patient limit of 275 patients prescribed buprenorphine at one time.

"Given that a relatively low number of providers account for most of the buprenorphine prescribing, providing targeted support to those willing to safely treat more patients may be a more promising strategy to increase medication treatment among people struggling with opioid addiction than primarily focusing on increasing the number of new prescribers," Stein said.