Billy Abbott, a retired Army medic, wakes at 6 every morning, steps on his bathroom scale and uses a cuff to take his blood pressure.

The devices send those measurements electronically to his doctor in Gulf Shores, Ala., and to a health technology company in New York, with the goal of helping control his high blood pressure.

Nurses with the technology company, Cadence, remotely monitor his readings along with the vital signs of about 17,000 other patients around the nation. They call patients regularly and follow up if anything appears awry. If needed, they can change patients’ medication or dosage without first alerting their doctors.

Abbott, 85, said he likes that someone is watching out for him outside his regular doctor appointments. “More doctors should recommend this to their patients,” he said.

Increasingly, they are.

Dozens of tech companies have streamed in, pushing their remote monitoring services to primary care doctors as a way to keep tabs on patients with chronic illnesses and free up appointment time — and as a new source of Medicare revenue.

But some experts say remote monitoring’s huge growth — spurred during the height of the coronavirus pandemic, when patients were hesitant to sit in crowded doctors’ waiting rooms — has outpaced oversight and evidence of how the technology is best used.

“It is the Wild West where any patient can get it if a doctor decides it is reasonable or necessary,” said Caroline Reignley, a partner with the law firm McDermott Will & Emery who advises health providers.

In 2019, Medicare made it easier for doctors to bill for monitoring routine vital signs such as blood pressure, weight and blood sugar. Previously, Medicare coverage for remote monitoring was limited to certain patients, such as those with a pacemaker.

Medicare allows physicians to get paid for the service even when the monitoring is done by clinical staffers who work in different places than the physician — an adjustment advocated for by telemedicine companies.

In just the first two full years, remote monitoring services billed to Medicare grew from fewer than 134,000 to 2.4 million in 2021, according to federal records analyzed by KFF Health News.

Total Medicare payments for the four most common billing codes for remote monitoring rose from $5.5 million in 2019 to $101.4 million in 2021, the latest year for which data is available.

Part of the allure is that Medicare will pay for remote monitoring indefinitely regardless of patients’ health conditions as long as their doctors say it will help.

For doctors with 2,000 to 3,000 patients, the money can add up quickly, with Medicare paying an average of about $100 a month per patient for the monitoring, plus more for setting up the device, several companies confirmed.

Medicare enrollees may face 20 percent in cost-sharing for the devices and monthly monitoring, though certain private plans through Medicare Advantage and Medicare supplement policies may cover those costs. The government allowed insurers to waive the patient cost-sharing during the pandemic.

About 400 doctors and other health-care providers repeatedly billed Medicare for remote patient monitoring in 2019. Two years later, that number had mushroomed to about 3,700 providers, according to Medicare data analyzed by KFF Health News. (The data tracks providers who billed more than 10 patients for at least one type of remote monitoring.)

Federal law enforcement officials say they are conducting investigations after a surge in complaints about some remote patient monitoring companies but would not provide details.

The Department of Health and Human Services Office of Inspector General issued a consumer alert in November about companies signing up Medicare enrollees without their doctors’ knowledge: “Unscrupulous companies are signing up Medicare enrollees for this service, regardless of medical necessity,” and bill Medicare even when no monitoring occurs.

In a statement to KFF Health News, Meena Seshamani, director of the federal Center for Medicare, part of the Centers for Medicare and Medicaid Services, did not say how CMS is ensuring only patients who can benefit from remote monitoring receive it. She said the agency balances the need to give patients access to emerging technology that can improve health outcomes with the need to combat fraud and make proper payments to providers.

While some small studies show remote monitoring can improve patient outcomes, researchers say it is unclear which patients are helped most and how long they need to be monitored.

“The research evidence is not as robust as we would like to show that it is beneficial,” said Ateev Mehrotra, a Harvard Medical School researcher.

A January report by the Bipartisan Policy Center, a D.C. think tank, warned about “a lack of robust evidence on the optimal use of remote monitoring” and said some policy and medical experts “question whether we are effectively ‘rightsizing’ the use of these services, ensuring access for patients who need it most, and spending health care dollars in effective ways.”

Denton Shanks, a medical director at the American Academy of Family Physicians, said remote monitoring helps patients manage their diseases and helps physician practices be more efficient. He has used it the past two years as a doctor at the University of Kansas Health System.

It has worked well, he said, though sometimes it can be challenging to persuade patients to sign up if they have to pay for it.

“For the vast majority of patients, once they are enrolled, they see a benefit, and we see a benefit as their vital signs come in the normal range,” Shanks said.

The size of the market is tantalizing.

About two-thirds of the more than 66 million Medicare beneficiaries have high blood pressure, the most common metric monitored remotely, according to physicians and the monitoring companies.

“The patient need is so enormous,” Cadence CEO Chris Altchek said. The company has about 40 nurses, medical assistants and other providers monitoring patients in 17 states. He said patients enrolled in remote monitoring experience a 40 percent reduction in emergency room visits. Cadence says 82 percent of its patients use the devices at least once every two days.

Timothy Mott, a family physician in Foley, Ala., said valuable appointment times in his office open up as patients who previously needed vital signs to be checked turn to remote monitoring.

Cadence nurses regularly contact Mott’s patients and monitor their readings and make changes as needed.

“I was concerned early on whether they were going to make the right decisions with our patients,” Mott said. “But over time, the dosage changes or changes in medication they are making are following the best guidelines on effectiveness.”

At the six-month mark, about 75 percent of patients have stayed with the monitoring, Mott said.

The advantages are apparent even to some providers who do not get paid by Medicare to offer the service.

Frederick Health, a Maryland system, provides remote monitoring to 364 high-risk patients and estimates the program saves the nonprofit system $10 million a year by reducing hospital admissions and ER visits. That estimate is based on comparisons of patients’ Medicare claims before they started the program and after, said Lisa Hogan, who runs the program.

The hospital pays for the program and does not bill Medicare, she said.

KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF — the independent source for health policy research, polling and journalism.