ePRO in Clinical Trials: Patient-Reported Outcomes From Home
Imagine you are a patient in a clinical trial for a new cancer treatment. Every three months, you visit the clinic, where a nurse asks how you have been feeling. Can you accurately remember your pain levels, fatigue, and mood over the past 90 days? Probably not. That is the fundamental limitation of traditional clinical trial data collection: it relies on brief, episodic snapshots. What if, instead, you could tell researchers exactly how you feel every day from home, using an app on your smartphone? That is the promise of electronic patient-reported outcomes, or ePRO, and the Clarity Clinical Solutions video on ePRO explains why it is transforming how trials capture the patient's voice.
What ePRO is
Electronic patient-reported outcomes are exactly what the name says: the use of digital devices, smartphones, tablets, or computers to collect information directly from patients about their health condition, symptoms, and quality of life. There are three main types.
First, validated questionnaires like the EQ-5D or SF-36, which measure overall health and quality of life. Second, daily symptom diaries where patients record pain, fatigue, nausea, or other symptoms in real time. Third, event-driven diaries where patients report when something specific happens, like a migraine, a seizure, or an asthma attack.
All of these are delivered electronically, with timestamps, automatic data transfer, and built-in quality checks that paper diaries cannot provide.
Why ePRO beats paper
The difference between paper diaries and ePRO is dramatic. With paper diaries, compliance rates are only 30 to 60 percent. Patients forget to fill them out, or worse, they backfill several days from memory right before a clinic appointment. That introduces recall bias. Studies have shown that when paper diaries are secretly fitted with electronic timestamps, the true completion rate is far lower than what patients claim.
With ePRO, compliance jumps to 80 to 95 percent. Push notifications remind patients to complete their diary. Each entry is timestamped exactly when it was made. Scores are calculated automatically, and the data flows directly into the study database. No manual entry, no backfilling, no lost diaries.
The adoption numbers are striking. Most new clinical trials now use some form of ePRO data collection, and a large majority of patients who have used both say they prefer ePRO over paper.
What the FDA says
The FDA has actively encouraged ePRO adoption. Its 2009 guidance on patient-reported outcome measures was a landmark document (FDA: Patient-Reported Outcome Measures: Use in Medical Product Development to Support Labeling Claims). It formally recognized that a patient's own report of their health status could serve as a valid endpoint for drug approval. The guidance defined what is required: content validity, does the instrument measure what it claims to measure; reliability, does it produce consistent results; and ability to detect change, can it capture meaningful differences in the patient's condition.
In 2023, the FDA updated this with guidance on digital health technologies for remote data acquisition in clinical investigations (FDA: Digital Health Technologies for Remote Data Acquisition in Clinical Investigations). This covered electronic equivalents, proving that an electronic version of a questionnaire performs the same as the paper original, and compliance with 21 CFR Part 11, the FDA rule for electronic records and signatures (21 CFR Part 11). These guidelines gave sponsors a clear regulatory path for ePRO adoption.
Bring your own device or provisioned devices
One of the key decisions in any ePRO study is whether patients use their own smartphones or receive a provisioned device. Bring your own device, or BYOD, is simpler and less expensive. Patients use phones they already know, and completion rates are high because people always carry their phones. But you lose control over the user experience: different screen sizes, operating systems, and font renderings can change how questionnaires appear.
Provisioned tablets cost more, several hundred dollars per device plus shipping and retrieval, but they guarantee every patient sees exactly the same interface. That matters for elderly populations who may not own smartphones, and for registration trials where data consistency is paramount.
Integration and safety alerting
For ePRO to work smoothly, it must integrate with the trial's data infrastructure. The ePRO platform sends data to the electronic data capture system either in real time or through scheduled batch uploads, which eliminates manual data entry. Integration with the clinical trial management system gives site staff visibility into patient compliance, so they can see who has not completed their diary and reach out. Increasingly, ePRO data is also linked to electronic health records, letting researchers compare what patients report subjectively with clinical measurements and lab values.
Perhaps most importantly, ePRO enables real-time safety alerting. If a patient reports severe pain or thoughts of self-harm, the study team is notified immediately.
The benefits and the challenges
The benefits of ePRO over paper diaries are well documented. Better data quality, because entries are timestamped and cannot be backfilled, automated skip logic prevents invalid responses, and there is a complete audit trail for regulatory inspection. A more patient-centric experience, because patients complete diaries from home at their convenience and their voice is captured directly, without being filtered through a clinician's interpretation. And cost and time savings, because manual data entry is eliminated, queries for missing data drop, and database lock comes faster. Sponsors typically see a large reduction in data management costs when switching from paper to electronic collection.
But ePRO comes with real challenges. On the patient side, the digital divide means older, lower-income, or less educated patients may not own a smartphone or have the digital literacy to use an app reliably. Linguistic and cultural validation is essential: every questionnaire must be carefully translated and validated for each language and culture where the study runs, which is expensive and time-consuming. Survey fatigue is real, and if questionnaires are too long or too frequent, compliance drops. On the operational side, choosing the right ePRO vendor requires careful evaluation, and if ePRO data is the primary endpoint for a registration trial, any data quality issue can jeopardize the entire study.
What makes ePRO work in practice
The compliance data are consistent across therapeutic areas: ePRO reliably achieves high completion rates when the design is right. The key factors are push notifications, short questionnaires of two to five minutes, user-friendly design, and making the questions feel personally relevant. Timing matters too. Morning completion rates are highest, while weekend compliance drops.
ePRO has also been adapted for special populations. In pediatric trials, gamified interfaces with avatars, animations, and rewards make diary completion fun, and children respond to smiley face scales instead of numeric ratings. For older adults, large fonts, high-contrast colors, and simple one-question-per-screen designs make ePRO accessible. In oncology, daily ePRO symptom monitoring enables early detection of treatment toxicity, and multiple oncology drugs have been approved with ePRO as a primary endpoint showing improved quality of life.
The bottom line
For decades, clinical trials treated patients as subjects who were measured, examined, and observed, but rarely asked how they actually felt. Electronic patient-reported outcomes changed that dynamic. They capture the patient's daily experience as validated, regulator-accepted data, data that can serve as a primary endpoint for drug approval. In doing so, ePRO transforms patients from passive subjects of research into active partners who contribute their own perspective to the scientific evidence. The patient's voice is not a nice-to-have addition to clinical research. It is an essential source of evidence that no lab test or imaging scan can replace.
This article is based on the Clarity Clinical Solutions video "ePRO - What if Patients Could Tell Researchers How They Feel Every Day — From Home?" Watch it here: ePRO - What if Patients Could Tell Researchers How They Feel Every Day — From Home?
References
- Clarity Clinical Solutions — ePRO - What if Patients Could Tell Researchers How They Feel Every Day — From Home? (video). https://www.youtube.com/watch?v=Yc4MCo-ZvvY
- FDA — Patient-Reported Outcome Measures: Use in Medical Product Development to Support Labeling Claims (2009 guidance). https://www.fda.gov/media/77832/download
- FDA — Digital Health Technologies for Remote Data Acquisition in Clinical Investigations (2023 guidance). https://www.fda.gov/regulatory-information/search-fda-guidance-documents/digital-health-technologies-remote-data-acquisition-clinical-investigations
- eCFR — 21 CFR Part 11, Electronic Records; Electronic Signatures. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-11
- ClinicalTrials.gov — Learn About Studies, including how patient-reported outcomes are collected in trials. https://clinicaltrials.gov/learn-about-studies