Ever since the start of the COVID pandemic, public health officials, politicians, and policymakers have pledged to “follow the science.” This devotion to scientific evidence is apparently something new. Ever since the Centers for Disease Control and Prevention published the Guideline for Prescribing Opioids for Chronic Pain—United States, 2016, federal and state agencies, governors and state legislatures have etched into policy what the CDC explicitly stated was not “settled science,” but what were meant to be general rules of thumb to aid practitioners, and would be:
[V]oluntary, rather than prescriptive standards. They are based on emerging evidence, including observational studies or randomized clinical trials with notable limitations. Clinicians should consider the circumstances and unique needs of each patient when providing care.
Most of the CDC guidelines were based on “type 4 evidence,” which the CDC defined as, “clinical experience and observations, observational studies with important limitations, or randomized clinical trials with several major limitations.”
That hasn’t stopped policymakers from codifying guidelines based on such weak evidence, effectively casting in stone what are now five‐year‐old suggestions. In other words, they weren’t following the science.
For example, 36 states have to date imposed limits on opioid prescriptions and total opioid dispensing per 100 persons has decreased more than 57 percent since its peak in 2012. The Centers for Medicare and Medicaid Services now limit opioid doses to 90 morphine milligram equivalents (MME) per day to Medicare and Medicaid patients, per the 2016 CDC Guidelines. Many states have 90MME restrictions for all other patients, and some require prescribing the overdose antidote naloxone when that threshold is reached.
Yet overdose deaths continue to mount, as they have done exponentially since at least the late 1970s, well‐before the approval of OxyContin in 1996. This should come as no surprise, since data provided by the CDC and the National Survey on Drug Use and Health consistently show no association between the number of prescriptions dispensed and the rate of non‐medical use of prescription opioids or of opioid use disorder. In other words, opioid deaths are primarily driven by non‐medical usage.
MMEs are based upon a formula promoted by the CDC whereby a clinician multiplies the dose of an opioid that is not morphine by a conversion factor to estimate its equivalent dose if it was morphine.
The notion of restricting opioid doses to 90 MME/day derives from a group of limited studies, among them an influential study by Bohnert, et al published in the Journal of the American Medical Association in 2011. That study followed roughly 150,000 chronic non‐cancer pain patients in the VHA system from 2004 through 2008 who were on chronic opioid medication. The overdose rate was 0.04 percent. But the researchers noted a correlation between dose (in MMEs) and the rate of overdose deaths. At roughly 100 MMEs the trend line began to level off. (This might have led some of the authors of the 2016 CDC Guideline to conclude that keeping the dose under 90 MME would be safest.) Bohnert, et al cautioned in their study’s conclusion:
This study documents a relationship between opioid prescribing and opioid overdose in a large, national, prospective cohort of individuals receiving opioid therapy for a variety of medical conditions. The risk of opioid overdose should continue to be evaluated relative to the need to reduce pain and suffering and be considered along with other risk factors.
University of Alabama Professor of Medicine Stefan Kertesz pointed out that follow up research led by Bohnert found the median overdose dosage was 60 MMEs and 86 percent occurred under 90 MMEs. Yet he cautioned policymakers:
Reliance on a simple binary dose metric is an extremely poor method for identifying persons at risk for adverse events while receiving opioids. It is insensitive and non‐specific…
…The correlation between dose prescribed and overdose event is a real finding. However, high prescription dose appears in large part to serve as a marker for multiple psychological and social vulnerabilities. This does not mean that every person receiving high doses has such vulnerabilities. However, it does suggest such vulnerabilities are likely to play a confounding role in the prediction of overdose events in large correlational data analyses. (emphasis in the original)
But that’s not all that is wrong with using morphine milligram equivalents to guide opioid prescribing. Pharmacology tells us that fixed doses of opioid drugs ignore the substantial genetic differences in metabolism between individuals. For example, the levels of the two primary enzymes the metabolize opioids can differ by 100‐fold from one person to the next, so the same dose of an opioid could be too low for a 100‐pound woman and too high for a 250‐pound man. Pharmaceutical research chemist Josh Bloom, the Director of Chemical and Pharmaceutical Science at the American Council on Science and Health wrote:
The CDC MME chart, in fact, the entire concept of morphine milligram equivalents may be convenient for bureaucrats but because of differences in the absorption of different drugs into the bloodstream, half‐life of different drugs, the impact of one or more other drugs on opioid levels, and large differences of the rate of metabolism caused by genetic factors, it is not only devoid of scientific utility, but actually causes far more harm than help by creating “guidelines” that are based upon a false premise. When a policy is based on deeply flawed science, the policy itself will automatically be fatally flawed. It cannot be any other way.
A 2017 white paper by pharmacologists Jeffrey Fudin, Mena Raouf, and Erica L. Wegrzyn stated:
Unfortunately, these equianalgesic conversion tables rely on a few assumptions that commonly are ignored by prescribers, dispensers, policymakers, and payers. Among these assumptions are that: 1) all the analgesic effect derived from a given medication is due to its action on the mu opioid receptor; and 2) all patients respond identically to all opioid medications. One group of opioids with multiple mechanisms of action, often referred to as “atypical opioids,” illustrates the dangers that can result from erroneously accepting these assumptions. Using common equianalgesic conversion tables to determine doses of these atypical opioids is fraught with danger, and potentially can result in patients unintentionally being under‐dosed or over‐dosed.
The American Society of Addiction Medicine, the most respected credentialling organization in addiction medicine, complained in 2016 that it is detrimental to apply the 90 MME metric to methadone and buprenorphine, used for Medication Assisted Treatment of substance use disorder:
Converting these recommended dosages [of methadone and buprenorphine] to morphine milligram equivalents (MME) (also known as morphine equivalent units (MEU)) reveals that they exceed the CDC recommendations regarding MME for chronic pain. The recommended 60–120 mg of methadone per day becomes 600 – 1,440 MME; the recommended range of 8–16mg buprenorphine becomes 80–160 MME.
The ASAM board recommended:
- When used for the treatment of addiction, methadone and buprenorphine should be explicitly excluded from legislation, regulations, state medical board guidelines, and payer policies that attempt to reduce opioid overdose‐related mortality by limiting milligram morphine equivalents (MME). Higher MME of these medications are necessary and clinically indicated for the effective treatment of addiction involving opioid.
- State medical boards should not use MME conversions of methadone or buprenorphine dosages used in addiction treatment as the basis for investigations or disciplinary actions against prescribers.
In 2019 the American Medical Association released a statement entitled, “Inappropriate Use of CDC Guidelines for Prescribing Opioids.” It stated: “Our AMA affirms that some patients with acute or chronic pain can benefit from taking opioid pain medications at doses greater than generally recommended in the CDC Guideline for Prescribing Opioids for Chronic Pain and that such care may be medically necessary and appropriate.” And, regarding MMEs, it stated:
Our AMA will advocate that no entity should use MME (morphine milligram equivalents) thresholds as anything more than guidance, and physicians should not be subject to professional discipline, loss of board certification, loss of clinical privileges, criminal prosecution, civil liability, or other penalties or practice limitations solely for prescribing opioids at a quantitative level above the MME thresholds found in the CDC Guideline for Prescribing Opioids.
Some argue that the CDC should never have gotten into the business of providing guidelines for opioid prescribing. Ordinarily this would come under the purview of the Food and Drug Administration. Well, even if it is late to the party, the FDA announced it is holding a “public workshop” in early June entitled, “Morphine Milligram Equivalents: Current Applications and Knowledge Gaps, Research Opportunities, and Future Directions.” Its stated purpose is to “provide an understanding of the science and data underlying existing MME calculations for opioid analgesics, discussing the gaps in these data, and discussing future directions to refine and improve the scientific basis of MME applications.” (emphasis added) It issued a request for comments.
Better late than never. Yet consider all the patients who have suffered from undertreatment of pain under the tyranny of MME restrictions and other codified CDC Guideline suggestions.
Stating “the CDC lacks both the authority and expertise to regulate drugs; that is the function of the FDA,” Dr. Josh Bloom submitted these comments to the FDA.
Aware of the misinterpretation and misapplication of its 2016 guidelines, the CDC issued an advisory in April 2019. The agency announced in December 2019 that it planned to update its guidelines.
Codifying guidelines casts them in stone. It makes nuance impossible. It incentivizes law enforcement agencies to view any deviation from the guidelines as a legal transgression and, as a result, frightens practitioners into abiding by the guidelines at the expense of their best medical judgment.
And it does not let anyone “follow the science.”
