High prescription drug prices are fast becoming a leading political topic, with medications like insulin emerging as a poster child for the issue. Nearly doubling in price from 2012 to 2016, the diabetes medication has commanded bipartisan attention on Capitol Hill and even a shoutout in a recent Netflix comedy special.

Voters say curbing such prices should be a top priority for lawmakers — and some presidential candidates are paying attention.

At an recent CNN town hall, Sen. Kamala Harris (D-Calif.), among the field of Democrats vying for the 2020 nomination, responded to a health care question by spotlighting insulin’s spiraling price tag.

“One out of four diabetes patients in our country cannot afford their insulin,” Harris said.

That would be a shockingly high number, researchers point out, and could become a talking point Democrats return to throughout the campaign season. The cost of insulin particularly resonates given diabetes’ incidence rates. The African-American community, for example, is 1.3 to 2.3 times more likely to suffer from diabetes than Whites, according to data from the Centers For Disease Control and Prevention.

According to the American Diabetes Association, about 1.25 million Americans have Type 1 diabetes —less common than Type 2 — and cannot live without insulin.

When asked about this particular statement, Harris’ campaign first cited a peer-reviewed study published in December, which looked at people with diabetes being treated at the Yale Diabetes Center in New Haven, Conn. Of 199 participants, 51 people — just over 25% — reported they either reduced or stopped taking insulin because of the cost.

The study is small and limited to one metropolitan area. But it likely paints a more-or-less accurate picture nationally, three health care academic researchers said.

“The characteristics of the people that were included look reasonably well-distributed across measures we’d be thinking about, like age, insurance type, race, ethnicity,” said Stacie Dusetzina, an associate professor of health policy at Vanderbilt University. “They probably are pretty much on target.”

The study also corresponds with other surveys, though they too have limitations.

One, commissioned by the American Diabetes Association and made public last May, polled about 530 people online whose demographics corresponded to the national data of people with the illness. About 27 percent of respondents suggested the price of insulin had “affected their past year purchase or use of insulin.”

There is also an online opt-in survey administered by T1 International, an advocacy group for people with diabetes. Its 2018 results and methodology are undergoing peer review and have not yet been published in full, said James Elliott, one of the organization’s trustees. He suggested it would likely ultimately support Harris’ “one out of four” talking point.

The caveat is that Harris’ comment is based on limited data, and only one of the papers has been peer-reviewed.

Though insulin’s price has skyrocketed in recent years, no sizable national survey or study has tracked insulin affordability, said Dr. Jing Luo, an instructor at Harvard Medical School who was involved with the Yale study and has researched insulin pricing more generally.

That perhaps limits any effort to make an argument about insulin access nationwide, or at the very least requires some extrapolation.

That said, the one-in-four figure is “more true than not,” Luo said.

“It’s as accurate as the data available allows,” Luo said. “It’s a reasonable estimate. Really, there’s no data to suggest otherwise.”

We also asked about Harris’ specific word choice: “cannot afford their insulin.” All the research examining this issue doesn’t ask that precise question, but rather, asks if the cost has resulted in a patient’s purchasing or using less medication.

That, analysts said, is, in fact, a good proxy for whether people can’t afford insulin. And it may understate the problem, said Dr. Kasia Lipska, the endocrinologist who led the Yale study, since it doesn’t account for people who keep buying medication but skimp on groceries or other necessities as a result.

This story was produced by Kaiser Health News, an editorially independent program of the Kaiser Family Foundation.