12 Technology QuarterlyThe quantified self TheEconomistMay7th 2022
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Economist.com/technology-quarterlymal outcome in drug trials for asthma, arthritis, heart failure, Par
kinson’s disease and cystic fibrosis. Measuring how much a per
son walks can provide a more objective, or at least complemen
tary, picture of a drug’s effect on pain or mood than the standard
practice of asking people to give a rating on a scale.
Most important, devices that unobtrusively monitor patients
as they go about their lives have allowed medical researchers to
see, for the first time, how patients experience a given disease and
treatment in their natural habitat. Nobody sleeps well in a phar
maceutical company’s sleep lab. The most widely used test of car
diovascular and physical fitness is the “sixminutewalk test”,
which is the distance that someone can walk in the span of six
minutes. It involves a patient pacing up and down a hospital corri
dor while a nurse with a clipboard records the result.
This has been simplified by fitness trackers, some of which
have added the sixminute test to their repertoire of movement
metrics. An Apple Watch, for example, makes its estimates using
multiple metrics from its sensors that are passively observed over
long periods of a user’s normal behaviour (rather than a single six
minute walk). Validation studies in people over 65 show that this
algorithmic estimate is highly accurate.
The inclusion in drug trials of measures
that reflect patients’ quality of life might help
people choose treatments that best suit their
priorities. At the moment, new cancer drugs
are considered a success even if they prolong
patients’ lives by just a few months. Many can
cer patients, however, care much more about
what they can do in the months that they sur
vive the disease than about stretching their
lives a little longer.
They would choose a treatment that might
promise fewer extra days but a greater chance
that they would be able to do what matters to them, such as being
able to lift up their grandchildren. Pharmaceutical companies are
starting to include such metrics among the goalposts they set for
new drugs.
Wearable sensors have also opened clinical trials to patients
who would otherwise be excluded from them, says Andy Coravos
from HumanFirst, an organisation which helps drug companies
deploy connected devices for monitoring trial participants at
home. She raises the example of Duchenne muscular dystrophy, a
musclewasting disease. The typical primary outcomes for medi
cines developed for the disease are a sixminutewalk test and a
fourstair climb test. But 60% of sufferers are in wheelchairs,
which means that they cannot participate. So it is unclear what the
treatments can do for them. An armband tracking upperbody mo
tion makes it possible to include them in trials.
Academic studies of nondrug interventions, such as behav
ioural nudges to increase physical activity, are also using more
data from fitness trackers rather than asking participants to keep a
diary or fill in a questionnaire. One analysis of clinical trials regis
tered in America found that the number using connected devices
grew from 88 in 2007 to more than 1,100 in 2017. The majority of
those trials have not been by pharmaceutical companies, but by
research organisations such as the group led by Euan Ashley at
Stanford University which focuses on precision medicine.
Dr Ashley’s group was among the first to run, in 2019, a fully
digital trial in which participants never met a researcher faceto
face. Not long ago, he says, recruiting trial participants involved
putting up posters with tearoff bits of paper listing a number for
them to call. They would then need to go to the hospital and sit
down with a nurse to go over 17 pages of consent forms to sign up.
“If you could get 200 people in a few months, you’d be pretty hap
py,” he says.
Now, people can download the app for a study and sign up
while waiting in line for their coffee. The first time Dr Ashley’steam used this method for a study on physical activity 40,000 peo
ple enrolled in just two weeks and results were ready in a matter of
months. That was not an unalloyed benefit. Though the study was
very easy to join, it was also very easy to leave and about 80% of
participants had dropped out before the end, which was just two
weeks in. Even so, the final group was about ten times the usual
size for this line of research. The quantified life
This report has argued that wearable health and fitness trackers
can change the way people try to stay healthy and alleviate illness,
the way their doctors care for them, and the way populationlevel
health interventions are deployed. The digital health care that
wearables enable could make treatment more efficient, personal
ised and effective. In America digital therapies are used by lots of
people who might otherwise not receive care at all. Mentalhealth
care from an aitherapist may not always be as good as from a hu
man being. But it can be accessed a lot more easily by people who
cannot afford the payment or time off to see a doctor, or where
there is a shortage of mentalhealth specialists.
Automated, roundtheclock monitoring
of patients with chronic conditions (the big
gest users of health care) can greatly improve
their treatment and outcomes. Done right, it
can also help doctors treat more of them with
out being overstretched. This model of care
can make a big difference in poor countries,
where there are not enough specialists.
About a third of deaths globally are from
cardiovascular disease and more than three
quarters of those deaths are in low and mid
dleincome countries. It may seem hard to
imagine that wearable devices with heart
monitoring functions will become widespread in developing
countries like India. But look at smartphones. In 2021, 54% of Indi
ans already owned one. Deloitte, a consulting firm, reckons that
by 2026, the country will have 1bn smartphone users, and will be
the world’s secondbiggest manufacturer of the devices. Many Af
rican countries have skipped developing a personalbanking sec
tor by establishing mobilephone payment systems that are now
used for almost everything.
But even in a developed country like America, a digital divide
exists whereby many people cannot afford internet access or lack
the digital literacy needed to make use of new health technology.
The new sensors and wearables technology are all very exciting,
says Yuri Maricich of Pear Therapeutics, but “how can we reduce
that to something that [works for] a single mom in the state of
Kentucky who is in a very difficult life situation, or a trucker who
is always on the road and trying to make ends meet?”
This sort of question is, all too often, an afterthought when
new consumer technologiesarebeing developed. To ignore it with
digitalhealth products wouldbesquandering a big opportunity to
improve health care for all.nThis model of care can
make a big difference
in poor countries,
where there are not
enough specialists