Decentralized clinical trials are clinical trials where some or all activities take place outside of traditional research sites, bringing the study to participants rather than requiring participants to travel to a hospital or clinic. Instead of repeated in-person visits, people enrolled in these trials might submit health data through wearable devices, have blood drawn by a nurse who visits their home, or check in with a study doctor over video. The concept gained massive traction during the COVID-19 pandemic, and by the end of that first pandemic year, 76% of sponsors and contract research organizations had integrated at least some decentralized elements into their trials.
How They Differ From Traditional Trials
In a traditional clinical trial, nearly everything happens at a designated research site. Participants drive to a hospital or university clinic for screening, receive the study drug on-site, get blood work done in the facility’s lab, and return for follow-up visits on a fixed schedule. This model works, but it creates real barriers. People who live far from major medical centers, who can’t take time off work, or who have mobility limitations often can’t participate at all.
Decentralized trials shift those activities closer to where participants actually live. The FDA defines a decentralized clinical trial as one that “includes decentralized elements where trial-related activities occur at locations other than traditional clinical trial sites.” That can mean a participant wears a sensor that streams heart rate data to the research team in real time, fills out symptom questionnaires on a phone app, or receives the study medication by mail. The goal is the same quality of data with fewer logistical demands on the person enrolled.
Fully Decentralized vs. Hybrid Models
Most trials using decentralized elements don’t go fully remote. They use a hybrid model, blending traditional in-person visits with remote components. A participant might visit a clinic for an initial screening and periodic safety checks but complete everything else from home. This lets researchers handle procedures that require specialized equipment (like imaging) on-site while shifting routine data collection to digital tools.
Fully decentralized trials, by contrast, are 100% remote with no in-person clinician interaction. These trials rely entirely on mobile devices, video visits, recruitment platforms, and home delivery of study products. They’re far less common because many studies involve procedures or treatments that simply can’t be done remotely, but they’ve proven viable for certain types of research, particularly trials focused on medications taken orally or on behavioral and mental health interventions.
The Technology Behind Remote Participation
Several layers of technology make decentralized trials possible. Wearable devices and connected health monitors collect physiological data continuously, things like blood pressure, glucose levels, sleep patterns, or physical activity. These devices authenticate securely and stream data in real time into the study’s electronic data capture systems, giving researchers a far richer picture of a participant’s health than periodic clinic visits ever could.
Telemedicine visits replace many face-to-face check-ins. Participants meet with study physicians or nurses over video for safety assessments, symptom reviews, and dosing instructions. Meanwhile, electronic patient-reported outcome tools let participants log symptoms, side effects, or quality-of-life measures directly from a phone or tablet at set intervals throughout the day or week. When physical samples are needed, home health services send trained phlebotomists or nurses to a participant’s home for blood draws, urine collection, or vital sign measurements.
Impact on Who Participates
One of the strongest arguments for decentralized trials is their potential to bring in participants who would otherwise never enroll. Clinical research has long struggled with a lack of diversity. Trial sites tend to cluster in urban academic medical centers, which limits geographic and demographic reach.
The reality, though, is more nuanced than “remote equals diverse.” The ACTIV-6 trial, a large decentralized study, illustrates this well. Four months in, only about 20% of participants came from racial or ethnic minority populations. By 28 months, that figure had climbed to 46%, nearly half of all enrolled participants. But the increase came primarily from strategic selection of study sites in underserved communities, not from the remote elements themselves. Self-referral, where people find and sign up for the trial on their own, didn’t drive diversity gains nearly as effectively.
The study also revealed a gap in retention: minority participants were roughly three times more likely to drop out before receiving the study drug compared to other participants (3% vs. 1%). So while decentralized designs can remove geographic barriers, they don’t automatically solve deeper issues of trust, access, and engagement that have historically kept underrepresented groups out of clinical research.
Challenges and Limitations
Running a trial outside the controlled environment of a research clinic introduces real complications. Protocol adherence is harder to verify when participants are taking medications at home, using devices without supervision, or completing assessments on their own schedule. Sponsors have started using automated compliance monitoring tools that flag deviations in real time, but the risk of inconsistent data remains higher than in a setting where trained staff oversee every step.
Getting investigational drugs to participants safely adds another layer of complexity. Shipping medications directly to someone’s home means managing temperature-sensitive packaging, tracking chain of custody across multiple jurisdictions, and ensuring the right person receives the right product. Some trials have built centralized regulatory frameworks specifically for this purpose. The TREAT Now study, for example, used direct-to-patient drug shipping combined with remote monitoring to maintain compliance across different regulatory environments.
Technology access is a fundamental concern. Not every participant has a reliable internet connection, a compatible smartphone, or the comfort level needed to navigate digital health tools. This can create a paradox: a trial designed to be more accessible may inadvertently exclude people who lack digital literacy or broadband access. Solutions being explored include partnerships with telecom companies to provide subsidized devices, standardized platforms that integrate easily into existing systems, and ongoing technical support for both participants and site staff.
How Regulators View Decentralized Trials
The FDA has issued guidance specifically addressing trials with decentralized elements, signaling that regulators see these models as legitimate but requiring careful planning. The core expectations haven’t changed: data integrity, participant safety, and informed consent still need to meet the same standards as any traditional trial. What’s different is the way those standards are maintained. Researchers need to demonstrate that remote data collection is as reliable as in-clinic measurement, that participants truly understand what they’re consenting to even when the process happens digitally, and that the investigator retains meaningful oversight despite not being in the same room as the participant.
Regulatory frameworks vary by country, which creates additional complexity for global trials. A decentralized element permitted in the United States may face restrictions elsewhere, and sponsors running multi-country studies need to navigate these differences jurisdiction by jurisdiction.
Where Adoption Stands Now
The pandemic was the inflection point. Before COVID-19, decentralized elements existed but were niche. The sudden inability to bring participants into clinics forced the industry to adopt remote tools almost overnight, and most of those changes stuck. Among trials that incorporated decentralized elements during the pandemic’s first year, about 7% went fully decentralized while the rest used a hybrid approach.
Hybrid remains the dominant model. For most therapeutic areas, some in-person interaction is still necessary, whether for infusions, imaging, surgical procedures, or safety monitoring that requires hands-on examination. The shift isn’t toward eliminating research sites but toward being more intentional about which activities genuinely need to happen in a clinic and which ones can happen wherever the participant is. That recalibration, deciding visit by visit what needs to be on-site, is increasingly becoming a standard part of trial design rather than an experimental add-on.