Zombie statistic contributed to opioid crisis

Back in February, I shared an article from JAMA, reviewing the role of Joint Commission’s pain standards in the current opioid epidemic and some of the lessons learned.

The fourth lesson was this:

Fourth, carefully review the primary literature on issues of critical importance and do not simply repeat the claims of experts in previous articles. The 1980 letter to the editor by Porter and Jick suggesting that addiction is rare in patients treated with narcotics has been cited almost 1000 times. Yet the report is so brief, methodologically vague, and unlikely to be generalizable to recent medical practice that its finding should never have been disseminated without cautionary notes and calls for research.

Now, the New England Journal of Medicine, the journal that published the 1980 letter, has published a review of its impact.

The prescribing of strong opioids such as oxycodone has increased dramatically in the United States and Canada over the past two decades.1 From 1999 through 2015, more than 183,000 deaths from prescription opioids were reported in the United States,2 and millions of Americans are now addicted to opioids. The crisis arose in part because physicians were told that the risk of addiction was low when opioids were prescribed for chronic pain. A one-paragraph letter that was published in the Journal in 19803 was widely invoked in support of this claim, even though no evidence was provided by the correspondents (see Section 1 in the Supplementary Appendix, available with the full text of this letter at NEJM.org).

The authors reviewed the number of citations for this letter

We identified 608 citations of the index publication and noted a sizable increase after the introduction of OxyContin (a long-acting formulation of oxycodone) in 1995 (Figure 1)

Not only was it cited hundreds and hundreds of times, it was also misrepresented more than 80% of the time.

So . . . what was the impact of this letter?

In conclusion, we found that a five-sentence letter published in the Journal in 1980 was heavily and uncritically cited as evidence that addiction was rare with long-term opioid therapy. We believe that this citation pattern contributed to the North American opioid crisis by helping to shape a narrative that allayed prescribers’ concerns about the risk of addiction associated with long-term opioid therapy.

Their advice?

Our findings highlight the potential consequences of inaccurate citation and underscore the need for diligence when citing previously published studies.

This is why, in this blog, I’m always looking for sources and I try to share information from the actual study rather than press releases or abstracts. It’s always astonishing how often the actual study does not resemble the impression you’d get from other papers, press releases, and abstracts.

Be selective with your trust and verify. There are a lot of “zombie statistics” out there.