The biggest challenges to widespread mobile health adoption in the U.S. are reimbursement and lack of regulatory clarification. But despite these challenges, the mobile health industry is expected to experience tremendous growth over the next few years and address many of the disparities plaguing healthcare in the U.S.

This is according to a newly-released report by the Brookings Institute that looked at the mobile health market in both the U.S. and China. It found that despite the challenges the mobile health industry faces in both countries, together they will account for more than one-third of the entire world market by 2017.

The report detailed how mobile health technology can address some of the worst challenges in healthcare: rising costs, access disparities, aging populations and increased rates of chronic disease.

Providers recognize opportunities to take advantage of mobile health solutions as a way of addressing these challenges despite continuing obstacles, according to report co-author Darrell West, founding director of the Center for Technology Innovation at Brookings.

Most public and private plans do not cover consultations, diagnosis or treatments delivered via a mobile device, according to the report.

"This has slowed the adoption of mHealth initiatives and made it difficult to reap the benefits of the mobile technology revolution," wrote the report authors.

The majority of mobile health applications in use in the U.S. right now are not medical in nature, according to the report. They merely help patients track calories or exercise.

Developers have been reluctant to launch apps capable of treating or diagnosing a condition because they are unsure about when approval from the Food and Drug Administration might be required. But the FDA has taken a step in the right direction, according to West.

"The Food and Drug Administration has issued guidance, which has created greater certainty for device manufacturers. They have a better sense of what regulators are thinking and what the future direction will look like," he said, referring to a guidance document the FDA published in September 2013.

Some legislators hope the FDA's guidance will go even further. A bipartisan group of six senators —Michael Bennet (D-Colo.), Orrin Hatch (R-Utah), Tom Harkin (D-Iowa), Lamar Alexander (R-Tenn.), Mark Warner (D-Va.), and Richard Burr (R-N.C.) — sent a letter to the FDA on March 18 asking for further clarification and transparency.

"While the FDA's final guidance has provided clarity on the agency's approach to regulation of mobile medical applications, we believe more transparency is needed to avoid stakeholder confusion over how a wider range of medical software might be appropriately regulated," the senators wrote. "We urge the FDA to work with Congress to identify policies that will serve the best interests of patients and innovators alike."

The group asked the FDA how many emails it had received to the email address set up to answer questions about specific mobile applications. They also want to know what procedures and processes are used to determine if and how an application with novel features never classified by the FDA before should be regulated.

As lawmakers continue to address regulatory uncertainty, they should also work to clarify policies on reimbursement, the Brookings authors wrote. Use of remote monitoring devices and consultations through mobile devices would help improve the affordability of healthcare and help address access disparities.

While there's still much work to be done, West said the growth of mobile health applications will continue despite the barriers.

"It is impossible to overcome every challenge, but there still is considerable innovation even with these obstacles," he said.