Smartwatches can track COVID-19 symptoms, study finds
University of Michigan researchers found that new signals embedded in heart rate indicated when individuals were infected with COVID-19 and how ill they became.
If a COVID-19 infection develops, a wearable device may eventually be able to clue you in. A study at the University of Michigan found that a smartwatch can monitor how symptoms progress.
The study evaluated the effects of COVID-19 with various factors derived from heart-rate data. This method also could be employed to detect other diseases, such as influenza and the common cold, at home or when medical resources are limited, such as during a pandemic or in developing countries.
Tracking students and medical interns across the country, the University of Michigan researchers found that new signals embedded in heart rate indicated when individuals were infected with COVID-19 and how ill they became.
For instance, they discovered that individuals with COVID-19 experienced an increase in heart rate per step after the onset of their symptoms. Meanwhile, people who reported a cough as one of their COVID-19 symptoms had a much more elevated heart rate per step than those without a cough.
“We previously developed a variety of algorithms to analyze data from wearable devices. So, when the COVID-19 pandemic hit, it was only natural to apply some of these algorithms to see if we can get a better understanding of disease progression,” says Caleb Mayer, a doctoral student in mathematics at the University of Michigan and a co-first author of the study.
People may not internally sense COVID-19’s direct impact on the heart, but “heart rate is a vital sign that gives a picture of overall health," says Daniel Forger, a University of Michigan professor.
Millions of people are tracking their heart rate through wearable devices. This information is already generating a tremendous amount of data for researchers to analyze, says co-author Daniel Forger, professor of mathematics and research professor of computational medicine and bioinformatics at the University of Michigan.
“Heart rate is affected by many different physiological signals,” Forger explains. “For instance, if your lungs aren’t functioning properly, your heart may need to beat faster to meet metabolic demands. Your heart rate has a natural daily rhythm governed by internal biological clocks.” While people may not internally sense COVID-19’s direct impact on the heart, he adds that “heart rate is a vital sign that gives a picture of overall health.”
Among the total of 2,164 participants who enrolled in the student study, 72 undergraduate and graduate students contracted COVID-19, providing wearable data from 50 days before symptom onset to 14 days after. The researchers also analyzed this type of data for 43 medical interns from the Intern Health Study by the Michigan Neuroscience Institute and 29 individuals (who are not affiliated with the university) from the publicly available dataset.
Participants could wear the device on either wrist. They also documented their COVID-19 symptoms, such as fever, shortness of breath, cough, runny nose, vomiting, diarrhea, body aches, loss of taste, loss of smell, and sore throat.
Experts not involved in the study found the research to be productive. “This work is pioneering and reveals exciting new insights into the many important ways that we can derive clinically significant information about disease progression from consumer-grade wearable devices,” says Lisa A. Marsch, director of the Center for Technology and Behavioral Health and a professor in the Geisel School of Medicine at Dartmouth College. “Heart-rate data are among the highest-quality data that can be obtained via wearables.”
Beyond the heart, she adds, “Wearable devices are providing novel insights into individuals’ physiology and behavior in many health domains.” In particular, “this study beautifully illustrates how digital-health methodologies can markedly enhance our understanding of differences in individuals’ experience with disease and health.”
Previous studies had demonstrated that COVID-19 affects cardiovascular functions. Capitalizing on this knowledge, the University of Michigan endeavor took “a giant step forward,” says Gisele Oda, a researcher at the Institute of Biosciences at the University of Sao Paulo in Brazil and an expert in chronobiology—the science of biological rhythms. She commends the researchers for developing a complex algorithm that “could extract useful information beyond the established knowledge that heart rate increases and becomes more irregular in COVID patients.”
Wearable devices open the possibility of obtaining large-scale, long, continuous, and real-time heart-rate data on people performing everyday activities or while sleeping. “Importantly, the conceptual basis of this algorithm put circadian rhythms at the center stage,” Oda says, referring to the physical, mental, and behavioral changes that follow a 24-hour cycle. “What we knew before was often based on short-time heart rate measured at any time of day,” she adds, while noting that heart rate varies between day and night and also changes with activity.
However, without comparison to a control group of people having the common flu, it is difficult to determine if the heart-rate signals are unique to COVID-19 or also occur with other illnesses, says John Torous, an assistant professor of psychiatry at Harvard Medical School who has researched wearable devices. In addition, he points to recent data showing that many wearables, which work by beaming light through the skin, may be less accurate in people with darker skin due to variations in light absorption.
While the results sound interesting, they lack the level of conclusive evidence that would be needed to transform how physicians care for patients. “But it is a good step in learning more about what these wearables can tell us,” says Torous, who is also director of digital psychiatry at Beth Israel Deaconess Medical Center, a Harvard affiliate, in Boston. A follow-up step would entail replicating the results in a different pool of people to “help us realize the full value of this work.”
It is important to note that this research was conducted in university settings during the early phases of the pandemic, with remote learning in full swing amid strict isolation and quarantine mandates in effect. The findings demonstrate that physiological monitoring can be performed using consumer-grade wearable sensors, allowing research to continue without in-person contact, says Sung Won Choi, a professor of pediatrics at the University of Michigan who is principal investigator of the student study.
“The worldwide COVID-19 pandemic interrupted a lot of activities that relied on face-to-face interactions, including clinical research,” Choi says. “Mobile technology proved to be tremendously beneficial during that time, because it allowed us to collect detailed physiological data from research participants remotely over an entire semester.” In fact, the researchers did not have any in-person contact with the students involved in the study. “Everything was done virtually," Choi explains. "Importantly, their willingness to participate in research and share data during this historical time, combined with the capacity of secure cloud storage and novel mathematical analytics, enabled our research teams to identify unique patterns in heart-rate data associated with COVID-19.”
Stacey Khoury felt more fatigued and out of breath than she was used to from just walking up the steps to her job in retail jewelry sales in Nashville, Tennessee. By the time she got home, she was more exhausted than usual, too.
"I just thought I was working too hard and needed more exercise," recalls the native Nashvillian about those days in December 2010. "All of the usual excuses you make when you're not feeling 100%."
As a professional gemologist, being hospitalized during peak holiday sales season wasn't particularly convenient. There was no way around it though when her primary care physician advised Khoury to see a blood disorder oncologist because of her disturbing blood count numbers. As part of a routine medical exam, a complete blood count screens for a variety of diseases and conditions that affect blood cells, such as anemia, infection, inflammation, bleeding disorders and cancer.
"If approved, it will allow more patients to potentially receive a transplant than would have gotten one before."
While she was in the hospital, a bone marrow biopsy revealed that Khoury had acute myeloid leukemia, or AML, a high-risk blood cancer. After Khoury completed an intense first round of chemotherapy, her oncologist recommended a bone marrow transplant. The potentially curative treatment for blood-cancer patients requires them to first receive a high dose of chemotherapy. Next, an infusion of stem cells from a healthy donor's bone marrow helps form new blood cells to fight off the cancer long-term.
Each year, approximately 8,000 patients in the U.S. with AML and other blood cancers receive a bone marrow transplant from a donor, according to the Center for International Blood and Marrow Transplant Research. But Khoury wasn't so lucky. She ended up being among the estimated 40% of patients eligible for bone marrow transplants who don't receive one, usually because there's no matched donor available.
Khoury's oncologist told her about another option. She could enter a clinical trial for an investigational cell therapy called omidubicel, which is being developed by Israeli biotech company Gamida Cell. The company's cell therapy, which is still experimental, could up a new avenue of treatment for cancer patients who can't get a bone marrow transplant.
Omidubicel consists of stem cells from cord blood that have been expanded using Gamida's technology to ensure there are enough cells for a therapeutic dose. The company's technology allows the immature cord blood cells to multiply quickly in the lab. Like a bone marrow transplant, the goal of the therapy is to make sure the donor cells make their way to the bone marrow and begin producing healthy new cells — a process called engraftment.
"If approved, it will allow more patients to potentially receive a transplant than would have gotten one before, so there's something very novel and exciting about that," says Ronit Simantov, Gamida Cell's chief medical officer.
Khoury and her husband Rick packed up their car and headed to the closest trial site, the Duke University School of Medicine, roughly 500 miles away. There they met with Mitchell Horowitz, a stem cell transplant specialist at Duke and principal investigator for Gamida's omidubicel study in the U.S.
He told Khoury she was a perfect candidate for the trial, and she enrolled immediately. "When you have one of two decisions, and it's either do this or you're probably not going to be around, it was a pretty easy decision to make, and I am truly thankful for that," she says.
Khoury's treatment started at the end of March 2011, and she was home by July 4 that year. She say the therapy "worked the way the doctors wanted it to work." Khoury's blood counts were rising quicker than the people who had bone marrow matches, and she was discharged from Duke earlier than other patients were.
By expanding the number of cord blood cells — which are typically too few to treat an adult — omidubicel allows doctors to use cord blood for patients who require a transplant but don't have a donor match for bone marrow.
Patients receiving omidubicel first get a blood test to determine their human leukocyte antigen, or HLA, type. This protein is found on most cells in the body and is an important regulator of the immune system. HLA typing is used to match patients to bone marrow and cord blood donors, but cord blood doesn't require as close of a match.
Like bone marrow transplants, one potential complication of omidubicel is graft-versus-host disease, when the donated bone marrow or stem cells register the recipient's body as foreign and attack the body. Depending on the severity of the response, according to the Mayo Clinic, treatment includes medication to suppress the immune system, such as steroids. In clinical trials, the occurrence of graft-versus-host disease with omidubicel was comparable with traditional bone marrow transplants.
"Transplant doctors are working on improving that," Simantov says. "A number of new therapies that specifically address graft-versus-host disease will be making some headway in the coming months and years."
Gamida released the results of the Phase 3 study in February and continues to follow Khoury and the other study patients for their long-term outcomes. The large randomized trial evaluated the safety and efficacy of omidubicel compared to standard umbilical cord blood transplants in patients with blood cancer who didn't have a suitable bone marrow donor. Around 120 patients aged 12 to 65 across the U.S., Europe and Asia were included in the trial. The study found that omidubicel resulted in faster recovery, fewer bacterial and viral infections and fewer days in the hospital.
The company plans to seek FDA approval this year. Simantov anticipates the therapy will receive FDA approval by 2022.
"Opening up cord blood transplants is very important, especially for people of diverse ethnic backgrounds," says oncologist Gary Schiller, principal investigator at the David Geffen School of Medicine at UCLA for Gamida Cell's mid- and late-stage trials. "This expansion technology makes a big difference because it makes cord blood an available option for those who do not have another donor source."
As for Khoury, who proudly celebrated the anniversary of her first transplant in April—she remains cancer free and continues to work full-time as a gemologist. When she has a little free time, she enjoys gardening, sewing, or maybe traveling to national parks like Yellowstone or the Grand Canyon with her husband Rick.
Paralyzed By Polio, This British Tea Broker Changed the Course Of Medical History Forever
Robin Cavendish in his special wheelchair with his son Jonathan in the 1960s.
In December 1958, on a vacation with his wife in Kenya, a 28-year-old British tea broker named Robin Cavendish became suddenly ill. Neither he nor his wife Diana knew it at the time, but Robin's illness would change the course of medical history forever.
Robin was rushed to a nearby hospital in Kenya where the medical staff delivered the crushing news: Robin had contracted polio, and the paralysis creeping up his body was almost certainly permanent. The doctors placed Robin on a ventilator through a tracheotomy in his neck, as the paralysis from his polio infection had rendered him unable to breathe on his own – and going off the average life expectancy at the time, they gave him only three months to live. Robin and Diana (who was pregnant at the time with their first child, Jonathan) flew back to England so he could be admitted to a hospital. They mentally prepared to wait out Robin's final days.
But Robin did something unexpected when he returned to the UK – just one of many things that would astonish doctors over the next several years: He survived. Diana gave birth to Jonathan in February 1959 and continued to visit Robin regularly in the hospital with the baby. Despite doctors warning that he would soon succumb to his illness, Robin kept living.
After a year in the hospital, Diana suggested something radical: She wanted Robin to leave the hospital and live at home in South Oxfordshire for as long as he possibly could, with her as his nurse. At the time, this suggestion was unheard of. People like Robin who depended on machinery to keep them breathing had only ever lived inside hospital walls, as the prevailing belief was that the machinery needed to keep them alive was too complicated for laypeople to operate. But Diana and Robin were up for the challenges – and the risks. Because his ventilator ran on electricity, if the house were to unexpectedly lose power, Diana would either need to restore power quickly or hand-pump air into his lungs to keep him alive.
Robin's wheelchair was not only the first of its kind; it became the model for the respiratory wheelchairs that people still use today.
In an interview as an adult, Jonathan Cavendish reflected on his parents' decision to live outside the hospital on a ventilator: "My father's mantra was quality of life," he explained. "He could have stayed in the hospital, but he didn't think that was as good of a life as he could manage. He would rather be two minutes away from death and living a full life."
After a few years of living at home, however, Robin became tired of being confined to his bed. He longed to sit outside, to visit friends, to travel – but had no way of doing so without his ventilator. So together with his friend Teddy Hall, a professor and engineer at Oxford University, the two collaborated in 1962 to create an entirely new invention: a battery-operated wheelchair prototype with a ventilator built in. With this, Robin could now venture outside the house – and soon the Cavendish family became famous for taking vacations. It was something that, by all accounts, had never been done before by someone who was ventilator-dependent. Robin and Hall also designed a van so that the wheelchair could be plugged in and powered during travel. Jonathan Cavendish later recalled a particular family vacation that nearly ended in disaster when the van broke down outside of Barcelona, Spain:
"My poor old uncle [plugged] my father's chair into the wrong socket," Cavendish later recalled, causing the electricity to short. "There was fire and smoke, and both the van and the chair ground to a halt." Johnathan, who was eight or nine at the time, his mother, and his uncle took turns hand-pumping Robin's ventilator by the roadside for the next thirty-six hours, waiting for Professor Hall to arrive in town and repair the van. Rather than being panicked, the Cavendishes managed to turn the vigil into a party. Townspeople came to greet them, bringing food and music, and a local priest even stopped by to give his blessing.
Robin had become a pioneer, showing the world that a person with severe disabilities could still have mobility, access, and a fuller quality of life than anyone had imagined. His mission, along with Hall's, then became gifting this independence to others like himself. Robin and Hall raised money – first from the Ernest Kleinwort Charitable Trust, and then from the British Department of Health – to fund more ventilator chairs, which were then manufactured by Hall's company, Littlemore Scientific Engineering, and given to fellow patients who wanted to live full lives at home. Robin and Hall used themselves as guinea pigs, testing out different models of the chairs and collaborating with scientists to create other devices for those with disabilities. One invention, called the Possum, allowed paraplegics to control things like the telephone and television set with just a nod of the head. Robin's wheelchair was not only the first of its kind; it became the model for the respiratory wheelchairs that people still use today.
Robin went on to enjoy a long and happy life with his family at their house in South Oxfordshire, surrounded by friends who would later attest to his "down-to-earth" personality, his sense of humor, and his "irresistible" charm. When he died peacefully at his home in 1994 at age 64, he was considered the world's oldest-living person who used a ventilator outside the hospital – breaking yet another barrier for what medical science thought was possible.