Clinical Outcome Assessment

Original Editor - Adu Omotoyosi Johnson

Top Contributors - Adu Omotoyosi Johnson, Kim Jackson, Lucinda hampton, Tolulope Adeniji and Alexandra Stead  

Introduction

A clinical outcome assessment (COA) is a measure that describes or reflects how a patient feels, functions, or survives. In medical product development and clinical research, COAs are used to form trial endpoints and should be fit-for-purpose (i.e., measure outcomes that matter to patients and are supported by appropriate qualitative and quantitative evidence. Types of COAs include:

1. Patient-reported outcome (PRO) measures
2. Observer-reported outcome (ObsRO) measures
3. Clinician-reported outcome (ClinRO) measures
4. Performance outcome (PerfO) measures.

Measurement properties (what makes a COA usable)

When selecting or developing a COA, key considerations include:

• Content validity (does it measure what it intends to measure?)
• Reliability/measurement error (is it consistent?)
• Ability to detect change (responsiveness)
• Interpretability (including what counts as a meaningful change)
• Feasibility/burden (time, training, cost, accessibility)

Types of Clinical Outcome Assessments

Patient-Reported Outcomes (PRO)

• Outcome where the patient is the rater
• Rely on a patient’s direct responses to questions
• Responses may be recorded by the patient in a variety of ways such as on paper, via computerized questionnaire forms, or via interviews where the patient’s observations or reports are recorded exactly as spoken, without any interpretation (judgment) on the part of the interviewer.
• Patient’s direct report can capture a wide range of feelings and functions, as well as provide a direct measurement of how a patient feels, e.g., pain or low mood

Increasing interest in developing PRO COAs. FDA guidance on the topic has highlighted the regulatory agency’s interest in these instruments.

Clinician-Reported Outcomes (ClinRo)

• Reflects the evaluation of a patient's condition by a healthcare professional.
• Based on the report that comes from a trained health care professional after observation of a patient's condition. a good example of this is the pain rating scale.

Observer-Reported Outcomes (ObsRo)

• Measurement based on an observation by someone other than the patient or a health professional.
• Usually done by patient's non-clinical care giver, family or anyone living around patient and observes the patient in daily life. A good example is the assessment of a patient's cognition.

Performance Outcome (PerfO)

• The patient is assessed, but no rater judgment impacts the measurement, categorized as COAs because a patient’s motivation or volition is involved in the task performance.
• Based on the patient’s performance of a defined task that is quantified in a specified way that does not rely on judgment to determine the rating.
• Include instruments such eg distance walked in 6 minutes and Timed up and go (TUG)
• Clinician or observer is administering and monitoring performance of the PerfO assessment task, this individual does not apply judgment to quantifying the performance.

The Context of Use of the COA

The context of use typically includes the following elements;

• Disease, injury, impairment or condition being treated
• Patient population demographics (age, disease severity, language, culture, education)

• Clinical treatment objectives and plan of treatment

Conclusion

• An outcome assessment, the patient assessment used in an endpoint, is the measuring instrument that provides a rating or score (categorical or continuous) that is intended to represent some aspect of the patient’s health status.
• Outcome assessments are used to define efficacy endpoints when developing a therapy for a disease or condition.
• Most efficacy endpoints are based on specified clinical assessments of patients.
• When clinical assessments are used as clinical trial outcomes, they are called clinical outcome assessments (COAs).