What is ePRO and how is it used in clinical trials?

What is ePRO?

Electronic patient-reported outcomes (ePRO) are a type of clinical outcome assessment where the patient directly provides information about their health through electronic means.

ePROs fall under the broader umbrella of patient-reported outcomes (PROs) which can be collected through paper-methods as well. All PROs are a report or measurement of the patients’ perspectives about the impact of disease and/or treatment on their health status, without the interpretation of a clinician or anyone else. Collecting data from patients directly without any interpretation is what makes this clinical outcome assessment unique compared to others.

Other types of clinical outcome assessments (COAs), according to the FDA definition:

  • Observer-reported outcome (ObsRO) measures: Measurement based on a report of observable signs, events or behaviors related to a patient’s health condition by someone other than the patient or a health professional.
  • Clinician-reported outcome (ClinRO) measures: Measurement based on a report that comes from a trained health-care professional after observation of a patient’s health condition.
  • Performance outcome (PerfO) measures: Measurement based on standardized task(s) actively undertaken by a patient according to a set of instructions.

How are ePRO used in clinical trials?

ePROs are used by clinical researchers to gain insight into patient experiences, responses to study treatments, or the effectiveness of a study treatment over time.

ePRO are typically measured using digital questionnaires filled out by patients before treatment, over the course of a clinical trial and after treatment. These questionnaires can gather data on overall well-being, physical health, mental health, satisfaction with the care being received, side effects, or any other concept that researchers may want to gain insights into.

For example, cancer patients might self-rate their pain levels before and after treatment, which can allow study physicians to see whether the treatment has altered participants’ pain scores.

The most common type of ePRO questionnaire asks questions related to symptoms, side effects, functioning at work or school, emotional well-being, social interactions, family relationships, daily activities like eating and sleeping, etc. – in general, anything related to quality of life and treatment progress for patients with any disease or condition.

What are the benefits of using ePRO?

ePROs are important because this data gives study researchers and physicians a better idea of how well the study treatments are working in real-time and allows them to make informed decisions regarding adjusting dosages, changing treatment schedules, or making any other changes (within the parameters of the trial being conducted) that may improve patient outcomes. By asking patients about their direct experiences with treatments, researchers can better understand how study drugs/treatments work and if there are any side effects that may not be obvious from blood tests or other laboratory work.

Here is a summary of some of the benefits of using ePRO:

  • Real-time data collection - The ability to collect data in real-time as opposed to waiting until the end of a study or survey period before obtaining results. This real-time data can help identify potential adverse reactions or unexpected side effects before they become widely apparent, and can be used to make changes to treatment plans or study design.
  • Reduced bias - With ePRO, participants can enter their own responses and are not necessarily subject to bias that may arise from needing to select from amongst a few predefined answers. Further, collecting data frequently over the course of the study increases the overall amount of data obtained and reduces biases that could arise from daily differences in mood or other fluctuating non-study-related factors, overall increasing the robustness of the data collected.
  • Increased participation - Research has shown that ePRO can increase survey response rates by 50% or more relative to paper-based surveys. This means that researchers can collect significantly more data and gain a better understanding of patient experiences—which could translate into clearer results, and eventually to better treatments being developed.
  • Reduced costs - With ePRO, researchers or trial sites can use the same data collection platform for multiple studies at once, and ePRO avoids the necessity for paper forms, printers, manual data entry tasks, and physical locations for survey collection, which in turn reduces staffing and infrastructure costs.
  • Increased data collection speed - Instead of having to send paper surveys by mail or make participants come to the study site to fill them out, researchers can collect responses instantly via electronic methods. This can improve the turnaround time from data to conclusions/results, and facilitates comfortable experiences for the trial participants.
  • Increased subject engagement and retention - With ePRO, researchers can interact with participants in real-time, sharing information about symptoms, symptom evolution, how participants are feeling, and also providing the participant with further information about the study, their condition, or their outcomes. This two-way interaction helps researchers keep participants engaged and interested in the trial, making it more likely for them to remain in the trial while also engaging with their own health outcomes and continually learning.
  • Collect data from a wider range of participants - In some cases (namely in trials requiring very few or no in-person visits to the study site), ePRO allows people to take part in clinical trials remotely, opening up possibilities for participation to a wider range of people. This is beneficial for researchers and study sites because they can collect much more data from a larger group of people, and also removes geographical limitations that often make recruitment campaigns more difficult.


When properly utilized, ePRO can help researchers and trial sites gather in-depth insights into how well a study drug or therapy is working as well as patient satisfaction and experience, and in general enables the standardized, reliable, and customizable collection of data in real-time.

ePRO represent a key research methodology and technology supporting clinical trial sponsors and researchers in capturing patient health data. They can help standardize the way data is obtained by doctors and patients alike. It will be interesting to follow the evolution of ePRO solutions in the coming years and their adoption in clinical trials, as they have already proven to be excellent tools for clinical research. We hope that that article has shed some light on ePRO and helped you consider how they can help improve your future clinical trials.