Medicine at a distance

Step counts and measured activity predict mortality better than questionnaires do, and the relationship holds down to low levels of activity. Tens of millions of people now carry devices that count steps, measure heart rate and estimate sleep continuously. Large cohorts — UK Biobank's accelerometer sub-study, the All of Us programme, several national cohorts — have begun to link those signals to outcomes, and the early findings are strong and simple. Beyond that the evidence is mixed. Whether continuous monitoring improves outcomes when acted on has been tested mostly in single conditions, with modest results. It should be noted that the people who wear devices are healthier and richer than those who do not, which limits what can be carried across to other populations. The measures themselves — sleep staging, heart-rate variability — are validated unevenly.

The health systems have moved regardless. England has built thousands of "virtual ward" beds since the pandemic, in which people who would have been admitted are monitored at home. Hospital-at-home services on the same model run in Australia, Spain and the United States. The trials that preceded them, mostly small, found similar mortality and readmission to inpatient care for selected patients, and at lower cost. Whether that holds at scale, for the patients actually enrolled rather than those selected for trials, is being evaluated now, and early English results are mixed on admissions avoided. Telehealth consultations rose tenfold in the pandemic and have settled well above the 2019 level, with little outcome evidence either way.

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