Chronic pain — pain that lasts at least 12 weeks — affects hundreds of millions of people globally. In 2016, an estimated 20% of U.S. adults (approximately 50 million) reported having long-term pain, while 8% (20 million) had high-impact pain stemming from headaches, arthritis pain, and neurogenic pain. Back pain is among the most common, with 16 million of all adults reporting experiencing it. So is COPD, or chronic obstructive pulmonary disease, which is also estimated to affect 16 million adults.

Prescription drugs and in-person consultations are two avenues sufferers often pursue, but former Foodora CEO Konstantin Mehl and Manuel Thurner sought less expensive and more sustainable forms of treatment. Their work led to Kaia Health, a four-year-old digital therapeutics startup whose apps tap AI and motion-tracking technology to ease pain. Kaia launched in the U.S. in September 2018 following successful pilots in Germany and the U.K., and it’s generated a fair amount of buzz, managing to rack up more than 275,000 downloads in three years — 100,000 in Germany alone in its first year of availability.

Riding on that momentum, Kaia Health today announced that it’s secured $8 million in funding from Optum Ventures, following a $10 million series A financing round in January 2019 and a $4 million seed round in June 2016. The new capital brings its total raised to over $20 million, and Mehl says it’ll be used to accelerate U.S. sales growth and R&D and to expand the supporting base of clinical evidence.

“The investment from Optum Ventures will allow us to explore integration opportunities throughout the complete patient treatment journey,” said Mehl. “We are proud to partner with Optum Ventures, a company at the forefront of improving health care.”

Kaia’s iOS and Android apps were developed with the help of physiotherapists, pain management physicians, orthopedic surgeons, and clinical psychologists, the company claims, and are registered as Class 1 medical devices with the Food and Drug Administration. They serve up video clips covering basic back and COPD pain information and step-by-step physiotherapy exercises, in addition to psychological strategies, such as mindfulness and muscle relaxation.

During each of the over 120 15-minute exercises, in-app computer vision models track connective points on the body through a device’s front-facing camera while an on-screen wireframe model illustrates the steps. Audio feedback informs users whether they’re performing exercises correctly and how they might improve, and a built-in chat tool allows them to consult with a physiotherapist or sports scientist on questions related to specific moves.

The apps aren’t free — subscription plans start at $24 for three months after a seven-day trial — but thanks to reimbursement deals with German health insurance companies including Barmer, Germany’s largest health insurance company, they’re available at no charge to about 20 million patients.

Most users stick with the program. Kaia claims about 40% of first-time users continue to perform the exercises roughly 3 times a week for a minimum of six months.

Self-service meditation apps and services are all the rage lately. There’s Simple Habit, which competes with Headspace, Pause, CalmShine, BioBeats, and Digg cofounder Kevin Rose’s Oak — a few of which have a significant funding advantage. Calm raised $88 million at a $1 billion valuation in February, while Headspace brought in a $36.7 million round two years ago.

But despite their prowess for fundraising, few have been clinically validated, pointed out Optum Ventures partner Heather Roxborough. In a study conducted at the Technical University of Munich’s Center for Pain Therapy and other “leading” institutions in Germany, Kaia’s app-based approach reduced lower back pain by 40%.

“Kaia Health has taken a technology-led approach to create digital therapeutics that will make treatment more accessible to patients who need it,” she said. “We believe Kaia Health’s digital therapeutic solutions will benefit those suffering from MSK disorders and are excited about its application in other indications.”