A Diagnosis in Search of a Disease?

Back in 2016, my doctor told me I was prediabetic: my blood sugar level was above normal, and if I didn’t do something about it, I could wind up with type 2 diabetes. That scared me. I know what a dreadful disease diabetes can be when it gets out of hand. 

I took the diagnosis seriously, but now I’m questioning that, thanks to a study of older people, published recently in JAMA Internal Medicine. Its results suggest that, in focusing on prediabetes, health authorities may be medicalizing a change in blood glucose (blood sugar) that’s usually just a normal result of aging. 

The suggestion that something may have been “medicalized” always grabs me, because decades ago when normal menopause was medicalized—redefined as a disease that needed treatment—I took estrogen for years, like millions of other women. It wasn’t until 2002 that a huge study revealed the risks we all ran from being treated with female hormones.  

In the prediabetes study, the researchers tracked the blood sugar levels of more than 3,400 individuals between the ages of 71 and 90. None of them had diabetes when the research began, but almost three-quarters were prediabetic, meaning their blood glucose levels were higher than normal but not high enough to indicate they had diabetes. (Three-quarters isn’t an uncommon finding.) 

Half a dozen years later, fewer than 10 percent of the study’s subjects had developed diabetes, while for a much larger number, blood sugar readings had dropped back to normal. Research on older people, done in Sweden, reported similar results. 

That made me wonder about my own diagnosis. I did a bit of googling and learned that in later life, the pancreas ordinarily produces less insulin and the body becomes more insulin-resistant. (Insulin is a critical factor in moving glucose from the body’s bloodstream into its cells.) When there’s too little insulin, there’s too much glucose in the blood. 

I also learned that most previous research on prediabetes didn’t focus on older people like me—which suggested that earlier evidence, showing that a significant number of those who are prediabetic go on to develop full-fledged diabetes, may apply mainly to the middle-aged. 

But it turns out that prediabetes is actually a controversial diagnosis for those of all ages. The term was chosen by the American Diabetes Association (the ADA) in 2001, apparently because it was scarier—and more likely to motivate patients—than telling them they had “impaired glucose tolerance.”

In the years that followed, some critics objected that the parameters for prediabetes were arbitrary to begin with, and that in 2010, the ADA moved the goalposts. 

Testing for hemoglobin A1c is the easiest way to measure glucose in the bloodstream. 

  • Before 2010, you were considered prediabetic if your A1c was between 6.0 and 6.4 percent.
  • After 2010, the range began at 5.7 percent instead: prediabetes was from 5.7 to 6.4.  

You have actual diabetes if your A1c is 6.5 percent or above. 

Dropping the threshold for prediabetes from 6.0 to 5.7 percent may not sound like much of a change, but as the new definition was adopted by the Centers for Disease Control and Prevention (the CDC), along with doctors and others, it raised the proportion of American adults thought to have prediabetes from 11 percent to 35 percent—about one in three. Suddenly, medical experts were talking about “an epidemic of prediabetes,” and drug companies, medical providers and others were enjoying a financial bonanza.

The controversy over prediabetes continues. On one side, the CDC estimated in 2020 that between 15 and 30 percent of adults who are prediabetic would develop diabetes within five years. In an interview with the Wall Street Journal, Ann Albright, a former director of the CDC’s Division of Diabetes Translation, said, “It’s just not an option to stand by and watch millions of people march to diabetes.” 

Other defenders of the prediabetic diagnosis have pointed out that the lifestyle treatment program promoted by the CDC and the ADA focuses on changes that are good for us anyway: stop smoking, lose weight, eat better, exercise more and manage stress better. They add that, when patients are told they’re prediabetic, it motivates them to make these difficult changes, and studies show that, when they succeed, they’re less likely to develop diabetes. 

But the World Health Organization (WHO) discourages the use of the word prediabetes because it implies that the next step is diabetes, and often it’s not. Other critics argue that many doctors are treating prediabetes by prescribing drugs, rather than just lifestyle changes, and some of those medications can have serious side effects. The critics also say it’s wrong to scare patients unnecessarily, and they point out that the diagnosis alone can raise an individual’s health insurance premiums, and the costs of checkups, tests and treatments add up. What’s more, being told you’re prediabetic can change your self-image: suddenly, you no longer think of yourself as healthy. 

Geriatrician Kenneth Lam, MD, from the University of California in San Francisco, was the coauthor of an editorial that accompanied the JAMA report on prediabetes in older people. He suggests that the threshold for prediabetes should be different for older people than the one set for the middle aged, and it should even be different for mild cases of diabetes itself. Certainly, more research is necessary. 

Meanwhile, what should you do if you’re told you’re prediabetic? For older adults, Lam believes prediabetes decisions should be made on a case-by-case basis. 

Consider, for example, just how high your A1c actually is, since those at the higher end of the range (closer to 6.4 percent) are more likely to become diabetic. Are you at risk for type 2 diabetes for other reasons, perhaps because you have a family history of the disease? Are you overweight, obese, or sedentary, do you have high blood pressure, or have you had heart disease or a stroke? There are other risk factors as well.    

After my own diagnosis, I changed my eating patterns and got more exercise. Once I’d dropped quite a bit of weight, my blood sugar level sank back into the normal range. Perhaps it would have gotten there even if I hadn’t adopted healthier habits, but I’m glad my fear of diabetes pushed me into making changes that were good for my health overall. 

But I do think warning bells should go off when a whole new diagnosis—like prediabetes—takes hold and becomes extremely common, especially when drug companies and others stand to make a lot of money as a result.