17.1  What are patient-reported outcomes?

Patient-reported outcomes (PROs) are any reports coming directly from patients about how they function or feel in relation to a health condition and its therapy, without interpretation of the patient’s responses by a clinician, or anyone else. PROs include any treatment or outcome evaluation obtained directly from patients through interviews, self-completed questionnaires, diaries or other data collection tools such as hand-held devices and web-based forms (US Food and Drug Administration 2006). Proxy reports from caregivers, health professionals, or parents and guardians (necessary in some conditions such as advanced cancer and cognitive impairment) cannot be considered PROs and should be considered as a separate category of outcomes.


PROs provide patients’ perspective on treatment benefit; directly measure treatment benefit beyond survival, disease, and physiologic markers; and are often the outcomes of greatest importance to patients. Reports from patients may include the signs and symptoms reported in diaries, the evaluation of sensations (most commonly classified as symptoms), reports of behaviours and abilities (most commonly classified as functional status), general perceptions or feelings of well-being, and other reports including satisfaction with treatment, general or health-related quality of life, and adherence to treatments. Reports may also include adverse or side effects (see Chapter 14). 


PROs are sometimes used as primary outcomes in clinical trials, particularly when no surrogate measure of direct benefit is available to capture the patient’s well-being. More often, PROs complement primary outcomes such as survival, disease indicators, clinician ratings and physiologic or laboratory-based measures. Figure 17.1.a shows those outcomes that are considered most often as important to patients within a classification of all outcomes. 


PROs may be collected using a measure (or instrument) that is disease-specific, condition-specific or generic. Disease-specific measures describe severity, symptoms, or functional limitations specific to a particular disease state, condition or diagnostic grouping (e.g. arthritis or diabetes). Condition-specific measures describe patient symptoms or experiences related to a specific condition or problem (e.g. low-back pain) or related to particular interventions or treatments (e.g. knee-replacement or coronary artery bypass graft surgery). Generic measures are designed for use with any illness group or population sample.


A glossary on PROs is available from the Cochrane Patient Reported Outcomes Methods Group web site (see Box 17.9.a).