Wearing your heart(rate) on your sleeve

Wearable health technology, such as heart rate sensors, can enable real-time health data collection in an accessible and equitable way. Sung Won Choi, M.D., is a pediatric oncologist at Rogel who specializes in bone marrow transplant. One of the main adverse outcomes of transplant is graft versus host disease, or GVHD. The diagnosis often involves invasive biopsies.

Early in her career, Choi was interested in identifying blood-based biomarkers of GVHD; over time, that interest spread to other tools that could provide signs to predict and monitor adverse reactions to treatments.

"If we can identify markers of complications before they happen, particularly through non-invasive methods, we could ensure patients receive timely care," Choi says.

Fever is an early hallmark of GVHD, as well as for a cytokine response to CAR T-cell therapy, a treatment where a patient’s own T-cells are modified to better recognize and attack cancer cells. Choi and collaborator Muneesh Tewari, M.D., Ph.D., professor of internal medicine and biomedical engineering at Michigan Medicine, thought wearable tech could help.

They got their chance to explore the tech as COVID-19 hit U-M’s campus. Their study of heart rate in U-M college students with COVID-19, published in Cell Reports Medicine, revealed that FitBit-detected heart rate changes correlated with symptoms in a predictive manner. Wearable, commercial-grade tech could work.

Choi and Tewari were also exploring the use of wearable tech to detect fever in cancer patients who had received CAR T-cell therapy. The results, published in Cancer Cell, were promising. Even a relatively low-tech wearable temperature sensor could alert the onset of fever before a normal thermometer.

The approach isn’t ready for "prime time," Choi says, but it shows promise. In one case, a patient had a detected fever and called the hospital, who had them come into the emergency department.

"Because of that, they received antibiotics sooner than they would have otherwise and possibly prevented a major case of sepsis," Choi says. "We have a few anecdotal cases, but they illustrate how early markers of complications can lead to timely interventions."

Because they’re using commercial-grade wearables, more people could have access to this type of care, Choi explains. "It wouldn’t make up for having high-quality, local health care, but it could help narrow that gap and improve care for people who, for a number of reasons, might not seek care otherwise."

It’s also cheaper, she adds. "What good is a million dollar device if patients won’t wear it?" And because many people are used to wearable tech monitoring their health, as with steps and heart rate, they might be more comfortable sharing those data for research.

"But it’s still very personal," Choi says. "It’s the stamp of your heart."

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