From Checkups to Continuous Care: What Wearable Medical Devices Change
Medicine has run on snapshots: a ten-minute consultation, months apart. Wearable sensors replace the snapshot with a stream. The evidence is now strong in diabetes and heart rhythm, and the business model is a subscription.
Summary
- Wearable medical devices replace occasional clinic readings with continuous data on glucose, heart rhythm, oxygen and blood pressure, and the evidence is now strongest in diabetes and atrial fibrillation.
- Abbott's REFLECT studies linked its glucose sensors to fewer heart-related hospitalisations, and in a 2026 randomised trial smartwatch screening picked up more atrial fibrillation in older, high-risk patients.
- Commercially, a wearable is a subscription: sensors replaced every 10 to 14 days. For India, with about 101 million people living with diabetes, the constraint is price and reimbursement, not demand.
For most of its history medicine has worked from snapshots. A patient feels unwell, sees a doctor for ten minutes, and a decision is made on what can be observed in that window. Then months pass before the next reading.
Chronic disease does not keep appointment times. Blood glucose, blood pressure, oxygen saturation and heart rhythm move all day and night, and a heart that behaves at a clinic at 11 a.m. may not behave at 3 a.m. Wearable medical devices replace the snapshot with a continuous record, and that changes what a doctor can see and when.
What counts as a wearable medical device
The line that matters is between consumer wellness trackers and devices validated for clinical use. They look alike on a wrist and sit in completely different regulatory and evidence categories. The clinical group includes:
- Continuous glucose monitors (CGMs): small sensors under the skin that read glucose every few minutes and replace repeated finger-prick tests.
- Cardiac wearables: smartwatch ECGs, adhesive ECG patches that replace the traditional Holter monitor, and optical sensors that track rhythm continuously.
- Respiratory and oxygen monitors: for COPD, asthma and sleep apnoea.
- Blood pressure wearables: wrist and cuffless devices for hypertension.
- Therapeutic wearables: insulin pumps, nerve stimulators and other devices that deliver treatment as well as measure.
Market estimates are loose. Grand View Research put the wearable medical device market at about $42.7 billion in 2024 and projects $168 billion by 2030; another firm put the same year at $120 billion. When estimates for one year differ by nearly three times, the definition is doing most of the work, so we would not build a plan on either.
Where the evidence is strong: diabetes
CGMs are the most mature category, led globally by Abbott's FreeStyle Libre and Dexcom's G7. Accuracy is measured as mean absolute relative difference (MARD), and Dexcom reports 8.2% to 9.1% for the G7. A head-to-head study in Diabetes Care in June 2025, with participants wearing several systems at once for 14 days, found the glucose metrics differed between devices by enough to change treatment decisions, a reminder that the sensors are not interchangeable.
The most important result came in May 2025. Abbott's REFLECT studies, drawing on the Swedish National Diabetes Register, which covers the great majority of people with diabetes in Sweden, associated FreeStyle Libre use with fewer hospitalisations for heart complications in both type 1 and type 2 patients on insulin. It was the first time a CGM had been linked to a cardiovascular outcome. It is an observational association, not a trial result, but it moves CGMs from convenience towards prevention.
Medtronic takes the idea furthest: its Guardian 4 sensor feeds the MiniMed insulin pump, which adjusts insulin automatically. The wearable no longer just reports. It acts.
Where the evidence is strong: heart rhythm
Atrial fibrillation is the most common sustained arrhythmia and a leading cause of stroke, and much of it causes no symptoms until the stroke. That makes it an ideal target for continuous monitoring.
A 2025 meta-analysis in JACC Advances, covering five studies and 1,133 participants, reported sensitivity of 83% to 100% and specificity of 79% to 100% for Apple Watch ECG detection of atrial fibrillation. A randomised trial published in JACC in January 2026 went further: in patients aged 65 or older with raised stroke risk, six months of smartwatch monitoring found new atrial fibrillation earlier and more often than usual care.
On the clinical side, iRhythm's Zio patch records continuous ECG for up to 14 days and is read with the company's algorithms, and it has largely displaced the older Holter monitor for many cardiologists. Our piece on AI in medical devices covers the software doing that reading.
Remote monitoring and readmissions
The case for hospitals rests on avoided admissions. UPMC in Pittsburgh has reported a 76% reduction in 30-day readmissions among high-risk patients enrolled in remote monitoring, and systematic reviews point the same way during the risky weeks after discharge. The size of the effect varies widely by programme and patient group, so treat single headline figures as upper bounds.
A wearable that nobody watches is an expensive bracelet; the value is in the team and workflow that act on the data.
What still gets in the way
- Accuracy where it matters most. Sensors perform worst when patients are sickest. One study of patients in intensive care after cardiac surgery found FreeStyle Libre MARD of 18.2%, too high for insulin dosing, and accuracy is also lower during hypoglycaemia and the first day of wear.
- Data overload. Continuous data produces continuous alerts. Without filtering and integration into hospital records, clinicians get more noise rather than less work.
- Privacy. Wearables collect intimate data around the clock, and rules on its storage, sharing and use are still settling in most countries, including under India's new data protection law.
- Access and payment. Users skew towards insured, urban and higher-income patients. Without reimbursement, the people who would benefit most are least likely to wear one.
- Blurred categories. Patients cannot easily tell a cleared medical device from a wellness gadget, and a missing clearance says nothing either way about safety.
The business model is a subscription
For medtech manufacturers, a wearable is the clearest example of the installed-base model we describe in the hidden profit engine of medical equipment. A CGM sensor is replaced every 10 to 14 days, an ECG patch per study, a monitoring platform per patient per month. Once a patient and their doctor trust a system, switching is rare, and clinical evidence like REFLECT deepens that trust.
What this means in India
The demand case is enormous. The ICMR-INDIAB study, published in 2023, estimated about 101 million people in India living with diabetes, with many more at risk, alongside a heavy and early burden of heart disease. Continuous monitoring fits that need better than infrequent clinic visits, especially outside the metros.
- For founders: price is the constraint, not interest. A device that costs what a Western sensor costs will stay niche. Design for a lower price point, a clear clinical claim, and a care team or hospital partner who acts on the data, since that is what makes the device worth paying for.
- For hospitals: remote monitoring after discharge can free beds and reduce readmissions, but only with a staffed programme behind it. Start with one high-risk group, such as heart failure or post-surgery patients, and measure readmissions before scaling.
- For investors: look for recurring sensor or service revenue, evidence beyond a single study, and a payer, whether insurer, employer, hospital or patient, who has shown they will keep paying. Those are the questions we test when advising on raising capital in healthtech.
The move from checkups to continuous care has started, and in diabetes and heart rhythm it rests on real evidence. The open question is how fast health systems, including India's, can reorganise to use the data well, pay for it fairly, and reach the patients who need it most.
How useful was this article?
One tap. It tells us what to write more of.
About the author
SRF Capital Studio
The next one
Get what we publish next, by email.
Working notes on raising, borrowing, protecting, growing and structuring capital in India. One email a week at most, and you can leave any time.
We use your address only to send this. See our privacy policy.
We store your address to send you these emails and nothing else. See our privacy policy.