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Story on speculative metformin health benefits needed a nod to potential harms


4 Star


An old-line diabetes drug may have new uses against diseases of aging

Our Review Summary

metformin word displayed on tabletResearchers are exploring the potentially broader utility of a well-known drug, metformin, which has traditionally been employed to control type 2 diabetes. Studies are under way to test the impact of the drug on everything from type 1 diabetes to dementia to cancer. Those efforts, to date, have offered varied results, from substantial to modest to none. This story is appropriately cautious about the ultimate value of the drug and delivers some useful information to the reader. However, its caution is somewhat overwhelmed by an anecdotal beginning in which a user testifies to the drug’s broader benefits. The discussion of potential harms is also not in balance with the enthusiasm over possible benefits.


Why This Matters

Though metformin has been around for a long time, it is only in the last 20 years or so that it has become the backbone of medical therapy for patients with type 2 diabetes mellitus — that is, diabetes due to insulin resistance in the tissues rather than not making it at all (that being type 1 diabetes). At the end of the piece, the article highlights the fact that where evidence supporting metformin’s use is very strong — i.e. patients with type 2 diabetes — the drug is probably underutilized. However, this article speculates about metformin’s potential for other conditions as almost a “fountain of youth.” [Quotation marks in the preceding sentence are ours, not the story’s.] The enthusiasm of the first paragraphs is eventually tempered by discussion of the stark lack of supporting evidence — but we worry that some readers may not make it far enough to see those restraining comments. We’re also concerned that the story does not mention the potentially serious side effects of metformin that are highlighted in the harms section of this review. There are important risks associated with this drug, and otherwise healthy people should not consider taking it for speculative and unproven health benefits.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

Part of why this topic is exciting is that metformin is relatively cheap, but the story doesn’t put a price tag on the drug. The story calls the drug “cheap” in the first sentence, and one could argue that cost lurks beneath the surface of one brief mention of a study that found only about half of newly diagnosed type 2 diabetics were prescribed metformin right off the bat. Other patients, experts speculate in the story, may be taking newer drugs being touted in advertising. One can infer that these newer drugs are more costly than metformin, but we think it would have been easy enough to provide some actual numbers that would have illustrated the meaningful difference.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The Not Satisfactory rating here stems in part from the prominent personal narrative that begins the story. In it, an individual begins taking metformin to help control her type 1 diabetes and reports a variety of positive outcomes, including becoming pregnant! This anecdote is far more vivid than the summaries of studies that follow, and it is likely to color the reader’s perception of the drug’s benefits. The story also suggests high up that there are a litany of potential health benefits observed in studies — for example, “those who take metformin tend to have lower rates of cancer, heart disease and dementia, and to live longer overall than those who take other drugs for diabetes.” Only later does it proceed to highlight that overall, the evidence so far does not support any of the claims made in the article’s title or the first few paragraphs. This framing, which front loads discussion of benefits and saves caveats and cautions for later, is unbalanced.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

The implication of this story is that metformin may help others besides those with type 2 diabetes. Other groups mentioned in the piece include those with type 1 diabetes, polycystic ovary disease, dementia, cancer and simply those who are aging (ie. everyone). The only side effect mentioned is stomach upset. So one could arguably conclude that everyone should be on this medicine. Not mentioned are the potentially dangerous side effects of metformin. Specifically it should not be given to those with acute or chronic kidney disease (a condition that commonly goes undetected). It can induce lactic acidosis which can be serious, even life-threatening. This is so well known that metformin is commonly held when patients are admitted to the hospital with an acute illness.

Does the story seem to grasp the quality of the evidence?


While we have a problem with the story’s framing as discussed above under Benefits, we think the piece does a reasonable job of eventually describing the overall limited quality of evidence available to support the claims that are made. That effort strikes a tone of caution with a hint of anticipation, which seems appropriate.

Does the story commit disease-mongering?


There is no overt disease mongering. However, the picture presented is so rosy in places that one might reasonably conclude that this is something everyone should take — like a multivitamin. That suggestion borders on disease mongering.

Does the story use independent sources and identify conflicts of interest?


By and large, this story gives the reader reasonable information to judge source bias. Scientists employed as sources are clearly identified as leading individual studies, although aside from the science journalist whose anecdote begins the story, one is hard-pressed to find sources independent of studies or funders. Underlying funding is not identified for most studies, although a funder is mentioned in one case. We’ll give the benefit of the doubt.

Does the story compare the new approach with existing alternatives?


We’re on the fence with this one. The start of the story focuses on new uses for metformin — uses that the story goes on to show are speculative and so far unproven (or disproven). It ends by highlighting that where the evidence for benefit exists — in patients with type 2 diabetes — metformin is underutilized compared to other diabetes medicines. However, the true comparison is for the potential new uses, and here the article should have stated clearly that until more evidence is available, metformin is unproven for these indications and that standard treatments should be the focus for the present. The story does warn that type 1 diabetics should never replace their insulin with metformin, but it doesn’t highlight the importance of maintaining standard treatments for the other conditions that are discussed. Again, we’ll err on the side of the story here.

Does the story establish the availability of the treatment/test/product/procedure?


The story clearly notes that metformin is an existing prescription drug marketed under a number of unpronounceable names.

Does the story establish the true novelty of the approach?


The story establishes that this is an old drug for diabetes that is receiving renewed interest for use in other disorders. It doesn’t overstate the claim to novelty.

Does the story appear to rely solely or largely on a news release?


There is enough original reporting here that we can be sure the story didn’t rely excessively on a news release.

Total Score: 7 of 10 Satisfactory


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