The volume of prescription opioids dispensed from retail pharmacies declined by 21% from 2008 to 2018, but the decline was not uniform across geographic areas, among types of patients or by type of prescriber, according to a new RAND Corporation study.

The study, published by the Annals of Internal Medicine, is the first to examine the decline in opioid prescriptions filled at retail pharmacies based on both volume and potency of the drugs dispensed.

The findings do not provide concrete answers about how much of the unnecessary prescribing of opioids has been eliminated. But the work demonstrates that there is a lot more nuance in the changes in opioid prescribing than we previously understood."

Dr Bradley D Stein, Study Lead Author and Senior Physician Researcher, RAND Corporation

There is wide agreement that the overprescribing of opioid medication for pain was a key driver in creation of the U.S. opioid crisis, which has led to widespread addiction and now kills more than 100,000 Americans annually.

State, federal and private initiatives have been undertaken to encourage physicians and other health providers to reduce the number of prescriptions written for opioids to treat pain. The number of opioid prescriptions peaked in 2011.

RAND researchers examined differences in opioid prescriptions filled at pharmacies during the periods of 2008 through 2009 and 2017 through 2018. The prescription information came from IQVIA Prescription data, which captures about 90% of prescriptions filled at U.S. retail pharmacies.

They used days' supply and total daily opioid dose to calculate per capita morphine milligram equivalents (MME) for opioid prescriptions filled during the study period. Because opioids are available in different forms, this measurement provides a better assessment of the total amount of opioids filled by patients as compared to just the number of pills dispensed.

The study found that over the study period, per capita MME volume declined the most in metropolitan counties (more than 22%) and in counties with higher rates of fatal opioid overdoses (a 35% decline).

Substantial variation existed both within and across states. In some states, MME volume per capita increased in multiple counties. In many other states, there were counties with both increases and others with substantial decreases. Counties that experienced substantial decreases in per capita MME often were adjacent to counties with per capita increases.

Most clinical specialties recorded declines in the MME volume per practicing clinician. The greatest decrease in MME volume per practicing clinician was among adult primary care physicians (40% decline) and pain specialists (15% decline) — the clinicians with the highest MME volume per clinician in 2008-2009.

The greatest percentage decrease was among emergency physicians (71% decline) — clinicians who are likely prescribing opioids predominantly to patients experiencing acute pain in acute care settings.

"These results suggest the effects of clinician and policymaker efforts to reduce opioid

prescribing have affected populations differently," Stein said. "Future efforts to enhance clinically appropriate opioid prescribing may need to be more clinically nuanced and targeted for specific populations."