It's not an 80/20 rule but if you are addicted to opiods you are likely to be visiting a small number of physicians in Ontario, according to a new analysis.

People in Ontario who have become addicted to opioids such as oxycodone and heroin are often prescribed a longer-acting but less euphoric opioid such as methadone or buprenorphine (also known as Suboxone®). About 30,000 physicians are licensed to practice medicine in Ontario so using administrative health-care databases housed at the Institute for Clinical Evaluative Sciences, the team identified 893 who prescribed methadone or buprenorphine more than once in 2014 to people eligible for the Ontario Drug Benefit Program (ODB) and stratified them into low-, moderate-, and high-volume prescribers and wrote about their results in the journal Drug&Alcohol Dependence

The top 10 percent of methadone prescribers (57 physicians) prescribed about 56 percent of the total days of methadone, the study found. Similarly, the 64 high-volume buprenorphine providers prescribed 61 per cent of the total days of buprenorphine. On average, each high-volume methadone prescriber treated 435 patients eligible for the Ontario Drug Benefits Program with methadone in the one-year study period. The patients had an average of 43 office visits that year, 43 urine drug screens and 190 days of methadone treatment. The authors say that translates into an office visit and urine drug test every four to five days. 

Furthermore, high-volume methadone providers billed for an average of 97 patients a day, approximately half of who engaged directly with the prescriber.  They billed Ontario Health Insurance Plan (OHIP) an average of $648,352 for all physician services provided to methadone patients eligible for the ODB in 2014, of which 45.7 percent was billed specifically for urine drug tests. 

Patterns among high-volume buprenorphine prescribers were different, with these physicians treating only 64 patients with buprenorphine in 2014, and billing 22 urine drug screens per patient. Similarly, patient volume was lower among these prescribers, with each physician billing for an average of 51 patients daily, of whom six were treated with buprenorphine. Total OHIP billings for services provided to buprenorphine patients was lower than for high volume methadone providers due to a smaller patient population, but similar to methadone, 40.6 per cent of the total cost was billed for urine drug screens.

The authors say the large number of patients seen by high-volume methadone prescribers could raise concerns about the quality of care patients receive, particularly when coupled with frequent clinic visits for urine drug screens.

They say that while regular urine drug screens have been shown to be of benefit in the first few months of treatment, there is no evidence that routine, ongoing weekly clinic visits and urine drug screens are associated with reduced drug use. Furthermore, spending several hours a week traveling to and from clinics, waiting to see the physician and providing urine samples may interfere with the patient's ability to meet his or her family and work responsibilities and can lead to patients discontinuing their addiction treatment. 

"Another cause for concern is the extreme clustering of opioid maintenance therapy services among a small group of physicians which creates a vulnerable opioid maintenance therapy system," said senior author Tara Gomes of the Li Ka Shing Knowledge Institute of St. Michael's Hospital. "It can be challenging to find physicians interested in treating this population, and any changes to this group of physicians may affect a large number of patients who are currently seeking treatment for their opioid addiction."