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SAN FRANCISCO — Plenty of health-tech startups have been buoyed by early data suggesting that their coaching and monitoring tools are generating improvements in patients with chronic diseases.

But a big question remains: Just how durable are those gains?


New data from one such company, Virta Health, underscore a tricky challenge for the burgeoning field: Even when an intervention looks promising, the apparent benefits often erode over time.

Virta, a San Francisco startup that uses digital coaching and monitoring to try to help patients reverse type 2 diabetes, is running a five-year study testing its approach. Promising results from year one were published last year. On Wednesday, the journal Frontiers in Endocrinology published results at the two-year mark.

After two years, the group of 262 patients enrolled in Virta’s program saw improvements that the group of 87 patients getting usual care did not. Those in the former group used less medication and lowered their weight, blood pressure, and a measure of glucose in the blood known as A1C. (Keep in mind that the study design has a crucial flaw — the patients were not randomly assigned between the two groups — that limits its power.)

On several metrics, however, Virta’s results didn’t look as good at the two-year mark compared to the one-year point: 26% of patients had dropped out of Virta’s program by two years, compared to just 17% one year in. And among patients who remained, 55% had reversed their condition two years in, compared to 60% a year earlier. (Virta defines type 2 diabetes reversal as reaching an A1C level below 6.5 percent and eliminating all diabetes medications except for metformin.)

That dropoff isn’t surprising after two years, nor should it be cause for alarm, said Dr. Ethan Weiss, a cardiologist at the University of California, San Francisco, who has advised Virta. “Even though they are seeing some attrition and some kind of reversion to the mean, they’re still doing really well,” Weiss said.

More broadly, Weiss said, the field must find ways to help more patients stay on track over time.

“This is the key, right? You don’t want people just to get better for a year or two — and then bounce back to where they were, which historically is what happens in almost all these scenarios,” Weiss said. (Weiss is also a co-founder and adviser at Keyto, a small San Francisco startup working on a device resembling a vaping pen to help dieters monitor when their body is in ketosis, a state in which fat, rather than carbohydrates, are burned for energy.)

The question of durability is also key to these companies’ business models, because insurers will be reluctant to pay for their services in the long term if patients’ health improvements prove to be short-lived.

Virta’s competitors are racing, too, to run longer and more rigorous studies in a quest to gather data that might help win over insurers. Omada Health ran a nonrandomized study of its program that found that engaged participants with prediabetes lost weight and lowered their A1C levels after three years. The company has another study in progress, this time randomized, that will report on patients’ outcomes after one year.

Another company, Livongo, recently published one-year results from a nonrandomized study it ran with the drug maker Eli Lilly; it found that diabetes patients in its program had lower medical spending than people employed by the same companies who did not sign up for Livongo. The company has other studies underway looking at outcomes over longer time periods.

For Virta’s part, the startup’s CEO and co-founder Sami Inkinen hailed the results published Wednesday as a validation of the company’s approach. In a phone interview with STAT, he drew a contrast between his company’s investment in research and some competitors’ touting of results from three-month studies.

“Three-month results mean nothing,” Inkinen said. “If you have one-year results, then you kind of have a reason to exist in treating type 2 diabetes. But I think two years is something that really gets everyone’s attention.”

Virta makes most of its money by charging health plans and employers for its services. Last fall, the startup announced a new business model: a health plan or employer would pay Virta only if its service works. Virta receives an initial fee only if the patient is sufficiently engaged with its program after one month. The second payment comes after a year, only if patients lower their A1C to a certain level determined on a case-by-case basis.

In both the clinical trial and the commercial setting, patients who enroll in Virta’s program get access to a digital messaging platform where Virta’s clinicians provide coaching. The company doesn’t endorse a specific diet, though its coaches do encourage many of its patients to adhere to a diet high on fat and low on carbohydrates, similar to the popular keto diet. Patients also get equipment that helps Virta monitor them, including a smart body-weight scale, a device for measuring levels of glucose and ketone in the blood, and lancets for sampling blood.

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