An electronic patient-reported outcome (ePRO) is a patient-reported outcome that is collected by electronic methods. ePRO methods are most commonly used in clinical trials, but they are also used elsewhere in health care. As a function of the regulatory process, a majority of ePRO questionnaires undergo the linguistic validation process. When the data is captured for a clinical trial, the data is considered a form of Electronic Source Data.
Methods
The two main methods currently used for ePRO are computers (including smartphones) and telephone systems.
Computers are most often touch-screen devices, ranging from wearables, hand-held devices and smartphones, through iPads and other Tablet computers. The smaller devices are often used as electronic diaries, designed to be used for symptom reporting on a daily basis. Larger devices are generally used in a clinical setting. Computers generally run dedicated ePRO applications - the use of the web for ePRO is not yet widespread. Typically a single question at a time is presented on the screen, with a set of possible response options. The user taps on the appropriate response with a finger or stylus, then moves on to the next questions.
Telephones normally use an interactive voice response system (IVR). The user calls into a dedicated phone line, and hears a spoken script that details the question, and the possible responses. Each response option is given a number, and the user presses the corresponding number key on the phone keypad to record the choice. IVR systems are more often used for diaries, with the patient phoning in e.g. from home, but they can be used in a clinic setting.
There are also a number of custom devices designed specifically for use as ePRO data collection devices.
Electronic diaries
Diaries are used when it is desirable to obtain frequent assessments over a period of time, for example when a condition fluctuates in severity. In such cases recall of severity over a period of time is unlikely to be accurate. Research has shown substantial bias in such summary recall, with ratings unduly influenced by how the patient is feeling at the time of making the rating, and by maximum severity rather than average severity during the assessment interval. Diaries can overcome this problem by recording severity either on a momentary basis ("How bad is your pain right now?") or by recalling over short periods ("How bad has your pain been today?"). However, when diary data is collected on paper, it is not known when the ratings are actually made, and there is evidence that compliance may be quite poor. In one study, patients were given an instrumented paper diary that recorded covertly when it was opened. The study showed frequent cases of "back-filling", filling in a batch of entries sometimes, often days, after they were due, and even in some cases of "forward filling", completing entries before they were due.
Electronic diaries automatically time-stamp all entries and can be set up to only allow entry within specified time windows. This improves compliance and ensures that true compliance can be documented. Documenting compliance is important if ePRO data are to be used to support regulatory applications. ePRO applications typically achieve compliance rates of over 80%, often over 90%. Electronic diaries also have benefits in that they only allow valid, in-range entries to be made. Devices such as PDAs allow reminders to be given to patients when entries are due. Systems generally transfer data promptly to a central server, allowing tailored feedback to be given to patients. This can also improve compliance. Electronic diaries also eliminate the need for manual editing and entry of data, time-consuming and error-prone processes.
Site-based
The other main setting for ePRO is the clinic, with questionnaires completed when patients come in for their scheduled visits. In this supervised situation, compliance is less of an issue. The questionnaires used in site-based ePRO are often longer and more complex than those used in diaries, assessing quality of life and activities of daily living, for example, in some detail. They more often include branching logic ("if YES continue with the next question, if NO, go to question 34"). Such branching logic can be handled automatically by the ePRO application, and it is often not necessary for the patient even to know that branching is taking place. This makes it easier for the patient to use.