Ride-sharing companies have plunged into the health-care business, seeing a big opportunity in ferrying the 3.6 million people who miss medical appointments each year to their doctors’ offices.

On Thursday, Uber announced the public launch of Uber Health, a dashboard that will allow health-care providers to schedule rides for patients. Lyft has crafted a number of partnerships over the past few years, working with health insurers, hospital systems and medical transport services to help patients get to and from medical care providers, in nonemergency situations.

No-show patients are a real problem in medicine, but it’s far from clear whether ride-sharing services scheduled by providers are the solution. A study of nearly 800 Medicaid patients in West Philadelphia found that offering to schedule free Lyft rides to and from primary care appointments didn’t decrease the number of missed appointments compared to a group of people not offered the service. That work, published in the journal JAMA Internal Medicine last month, calls into question whether simply expanding the availability of ride-sharing services would help solve the problem.

“We really thought ride shares would be super convenient. We were pretty surprised, actually, it did not work out,” said Krisda H. Chaiyachati, a primary-care provider at the University of Pennsylvania and the Veterans Affairs Medical Center. “I think we [as providers] tend to apply our choices of how we live our lives, and we kind of impose it on our patients’ lives. We probably all use ride-sharing services — I used one this morning. We think the same thing is going to apply to a sick person or a poor person, and that might not be true.”

Individual companies have reported benefits. CareMore Health System found in a pilot study in 2016 that using Lyft was cheaper than other forms of transportation and patients spent less time waiting for a ride. American Medical Response, a leading medical transportation company, has reduced complaints by 50 percent since partnering with Lyft.

[ The tech industry thinks it’s about to disrupt health care. Don’t count on it. ]

Chaiyachati said the study might provide clues about what kinds of patients could benefit from ride-sharing help. The study examined the use of ride shares in getting patients to primary-care appointments, but it’s possible that it might be more useful in settings where adherence to appointments may be more critical, such as oncology.

“The study results really contradicted what we’ve seen with other partners, again and again,” said Gyre Renwick, a vice president of Lyft Business.

Renwick said Lyft has been targeting groups of people, including elderly and poor patients in areas underserved by public transportation and people for whom missing an appointment — such as for dialysis or cancer treatment — could have major health repercussions and cause expensive hospitalizations.

Uber has been piloting its health service since last summer. One lesson learned from the experience is that many of the patients who use the service haven’t used Uber before and may not even have a smartphone. The company has had to use text messages to alert people without the Uber app or a smartphone to their rides — and even printouts and phone calls for some people.

“We’ve moved to a paper-based communication strategy, where we have forms we can provide for our customers,” said Jay Holley, head of partnerships at Uber Health. “Circle the make, model, license plate number [of the ride], and help people in the most analog possible way for a tech company.”

Who pays for the service depends on the partnership. Patients on Medicaid have transportation benefits that can be billed for the service. Providers often pay for the rides out of their own money.

One of the benefits of the digital services is accountability, for an area of medical spending that has been ripe for fraud, waste and abuse. Instead of paper receipts and faxes, the companies’ digital platforms can help ensure that rides are taking place as scheduled.

Read More:

In our eyes, Google’s software sees heart attack risk

Amazon, Berkshire Hathaway and JP Morgan Chase join forces to tackle employees’ health-care costs

Two visions for the future of health care are at war in Pittsburgh