Can apps manage our chronic health conditions?

From stumbling slowly out of bed, to doing active weights classes at the gym, Ewa-Lena Rasmusson's mobility has transformed during the pandemic.

The 55-year-old, from Stockholm, says it's all thanks to a Swedish app that uses artificial intelligence to create bespoke exercise plans designed to help alleviate joint pain.

Every day the app sends Ms Rasmusson a "nudge" to remind her to do a series of repetitions for five minutes, such as squats and leg lifts.

Video demonstrations help ensure she understands the correct technique, and her training is adjusted according to her feedback on how challenging or painful she finds it.

There's also a chat function within the app so she can message a real-life physiotherapist, who arranges regular video call check-ins too.

"I can really feel the difference," says Ms Rasmusson, who has struggled with knee pain. When she began the treatment back in March 2020 she could only manage a handful of squats, and now she is proudly "up to 21."

Alongside lifting barbells, she's recently been able to get back into cycling, and has even booked a family ski trip for next year.

The app, called Joint Academy, launched in 2014 with the goal of improving treatment for osteoarthritis. It was co-founded by Leif Dahlberg, a professor of orthopedics at Lund University in southern Sweden, and his son Jakob, now 30, who dropped out of his degree in computer sciences to launch the start-up.

The company says it offers an alternative to waiting in line for face-to-face physiotherapy, and solves the problem of patients being steered towards "high risk" and "expensive" operations, without the chance to try simpler treatments first.

During the pandemic, the younger Mr Dahlberg says the platform's user base has "leapfrogged maybe two or three years" ahead of its predicted growth.

Despite Sweden opting against formal lockdowns, operations were postponed across the country, seniors' exercise classes were cancelled, and patients and healthcare workers alike sought to limit face-to-face contact.

Almost 50,000 people have used Joint Academy since April last year, the company says, compared to 15,000 during its first six years in business. It is now the most common first-line treatment of chronic joint pain in Sweden.

"People with chronic ailments are often in the high-risk group for Covid, and in the pandemic they shouldn't be running into the clinic to get support," explains Jakob. "So it was very good for us to offload and reallocate resources in healthcare."

Joint Academy is a licensed physiotherapy provider in Sweden. It makes its money from regional healthcare authorities who pick up the bill for placing patients on its digital physiotherapy programmes.

Some patients are also referred via private health insurance providers. The company has raised 295m Swedish krona ($34.2m; £24.8m) in funding and had a turnover of 64m krona in 2020.

The app's success is part of a wider boom in specialist digital healthcare services in Sweden. These include Blodtrycksdoktorn, which offers bespoke treatment for patients with high blood pressure, migraine help service Migränhjälpen, and Mindler which gives online access to psychologists.

Around one in five Swedes used a digital healthcare app in autumn 2020, according to The Swedish Internet Foundation, including almost one in 10 pensioners.

Roger Molin is a digital healthcare expert, and a former national coordinator for chronic disease treatments. He says that the trend towards such health apps isn't surprising in a country with a tech-savvy population, and a long history of developing digital innovations, from Spotify to payments platform Klarna.

"I think they are really user-friendly," he says of the digital healthcare apps he's seen. He believes even greater public investment in digital healthcare is the answer to easing pressure on the health service in Sweden which, like many European countries, is battling with an ageing population.

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"If you are going to increase efficiency in Swedish healthcare, then you need to do something for people with chronic conditions, because people with chronic conditions stand for most of the costs in healthcare."

But not everyone is as excited. Sofia Rydgren Stale, who chairs the Swedish Medical Association, says that although healthcare apps are of "great importance" to the development of the country's healthcare system, there are ongoing debates about how to regulate the industry.

Concerns include monitoring the competences of therapists and doctors working for digital apps, and worries about "very aggressive marketing" from some of the private companies behind them.

"We also need more research," says Ms Stale. "When is it most appropriate to use a digital tool and when is it not?"

Plus, while Swedes tend to have a high level of digital literacy, she's worried some vulnerable residents will find it harder than others to access app-based services, which could fuel inequality if these are prioritised in future. "The healthcare sector should be open to everybody," she insists.

But Jakob Dahlberg, who is Joint Academy's chief executive, is far from worried about any criticism, pointing to the results of the firm's 10 peer-reviewed clinical studies.

"It works. There's really no more need to argue than that: the data speaks the truth," says Jakob.

For around 2,500 users, like Agneta Sjödin Portinson from Östersund in northern Sweden, the impact has even been so dramatic they've changed their minds about having surgery.

"I was very close to having an operation because I didn't see any other way out of it," says the 58-year-old.

Her hip pain used to be so severe she couldn't sleep at night, and often struggled to put on her shoes and socks in the morning. "Now it's all good… when I walk for a long time I might feel it a little when I get home, but other times, not at all," says Ms Portinson.

Jakob says Joint Academy now has "very big and global ambitions". It recently launched in the US, and is planning to branch out into other European countries and add lower back pain to its treatment offering.

In the UK - where around 10 million people have arthritis or other conditions that affect the joints - the app is already available, although it's not currently funded by the NHS.

Back in Sweden, Joint Academy users like Ms Rasmusson are confident the app's appeal will endure, even in countries where social-distancing recommendations have been relaxed, and physical appointments are more accessible again.

For her, a major part of the appeal has been skipping the journey to and from a traditional physiotherapy appointment, which she says would have been a hassle even before the pandemic.

"Travelling to the centre of Stockholm, getting help there, I would not have done it," she says. "I think that if I would not have got the app... I would have been in a terrible state."