Patient-reported outcome - AbsoluteAstronomy.com

A patient-reported outcome or PRO is a questionnaire used in a clinical trial

Clinical trial

Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...

or a clinical setting, where the responses are collected directly from the patient.

Overview

PRO is an umbrella term

Umbrella term

An umbrella term is a word that provides a superset or grouping of concepts that all fall under a single common category. Umbrella term is also called a hypernym. For example, cryptology is an umbrella term that encompasses cryptography and cryptanalysis, among other fields...

that covers a whole range of potential types of measurement but is used specifically to refer to self-reports by the patient. PRO data may be collected via self-administered questionnaires completed by the patient themselves or via interviews. The latter will only qualify as a PRO where the interviewer is gaining the patient’s views, not where the interviewer uses patient responses to make a professional assessment or judgment of the impact of the patient’s condition. Thus, PROs are a means of gathering patient rather than clinical or other views on outcomes. This patients' perspective can play an important role in drug approval.

Characteristics

A well-designed PRO questionnaire should assess either a single underlying characteristic or, where it addresses multiple characteristics, should be a number of scales that each address a single characteristic. These measurement “characteristics” are termed constructs and the questionnaires used to collect them, termed instruments, measures, scales or tools.

A questionnaire that measures a single construct is described as unidimensional. Items (questions) in a unidimensional questionnaire can be added to provide a single scale score. However, it cannot be assumed that a questionnaire is unidimensional simply because the author intended it to be. This must be demonstrated empirically (for example, by confirmatory factor analysis or Rasch analysis). A questionnaire that measures multiple constructs is termed multi-dimensional. A multi-dimensional questionnaire is used to provide a profile of scores; that is, each scale is scored and reported separately. It is possible to create an overall (single summary) score from a multi-dimensional measure using factor analysis or preference-based methods but some may see this as akin to adding apples and oranges together.

Questionnaires may be generic (designed to be used in any disease population and cover a broad aspect of the construct measured) or condition-targeted (developed specifically to measure those aspects of outcome that are of importance for a people with a particular medical condition).

The most commonly used PRO questionnaires assess one of the following constructs:

Symptoms (impairments) and other aspects of well-being
Functioning (disability)
Health status
General health perceptions
Quality of life (QoL)
Quality of life
The term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and politics. Quality of life should not be confused with the concept of standard of...
Health related qualiy of life (HRQoL)
Reports and Ratings of health care.

Measures of symptoms may focus on a range of impairments or on a specific impairment such as depression or pain. Measures of functioning assess activities such as personal care, activities of daily living and locomotor activities. Health-related quality of life instruments are generally multi-dimensional questionnaires assessing a combination of aspects of impairments and/or disability and reflect a patient’s health status. In contrast, QoL goes beyond impairment and disability by asking about the patient’s ability to fulfill their needs and also about their emotional response to their restrictions.

Validation and quality assessment

It is essential that a PRO instrument satisfy certain development, psychometric and scaling standards if it is to provide useful information. Specifically, measures should have a sound theoretical basis and should be relevant to the patient group with which they are to be used. They should also be reliable and valid (including responsive to underlying change) and the structure of the scale (whether it possesses a single or multiple domains) should have been thoroughly tested using appropriate methodology in order to justify the use of scale or summary scores.

Examples

Many of the common generic PRO tools assess health-related quality of life or patient evaluations of health care. For example, the SF-36 Health Survey (SF-36 Health Survey), SF-12 Health Survey (SF-12 Health Survey), the Sickness Impact Profile, the Nottingham Health Profile, the Health Utilities Index, the Quality of Well-Being Scale, the EuroQol (EQ-5D), and the Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey instruments are PRO instruments.

Condition-targeted tools may capture any of the constructs listed above, depending on the purpose for which they were designed. Examples include the Adult Asthma Quality of Life Questionnaire (AQLQ), the Kidney Disease Quality of Life Instrument, National Eye Institute Visual Functioning Questionnaire, Epilepsy Surgery Inventory, Migraine Specific Quality of Life (MSQOL), the Ankylosing Spondylititis Quality of Life questionnaire (ASQoL) and the Seattle Angina Questionnaire (SAQ), to name a few.

Terminology

The term PRO should not be confused with patient-based outcomes. The latter implies that questionnaire covers issues of specific concern to the patient. However, patient-reported implies only that the patient provides the information. This information may, or may not, be of concern to the patient.
The term PROs is synonymous with the increasing use of the term patient reported outcome measures (PREMs).

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