Chapter 9: Outcome Measures in the Field of Rehabilitation Medicine

INTRODUCTION: WHY DO WE NEED OUTCOMES?

The primary goal of rehabilitation is to optimize function and promote functional recovery for patients. Outcome measures are the objective tests and measures used to determine functional status in a standard and consistent way, and can quantify the effects of rehabilitation.

Outcome measures are also a method by which one can validate the efficacy of treatments. Such measures are becoming increasingly important as providers and payors focus more on value as opposed to volume in health care.

The systematic collection of outcome measures may help a provider identify functional limitations during an initial patient evaluation, select appropriate interventions, and establish goals for future planning (e.g., discharge from inpatient care).¹ Communication about the results of standardized outcomes among the interdisciplinary team establishes a common language for a comprehensive plan of care. Standardized outcomes are essential for high methodological quality of clinical trials.² Ongoing review of outcomes at an institutional level may be used for quality improvement, comparison across settings, analysis of cost-effectiveness, or health services research.^3,4

In spite of the many advantages to the use of outcome measures, there are many barriers to the practical use of outcome measures in clinical practice. Studies have shown a high degree of heterogeneity of outcome measures used in rehabilitation centers, even within the same diagnostic groups.⁵ This is true even in research studies; a review of outcome measures reported in randomized clinical trials (RCTs) in stroke rehabilitation found that 489 different measurement tools were used in 491 RCTs.² In 2009, less than 50% of physical therapists surveyed reported using standardized outcome measures.⁶ Barriers to the use of outcome measures have been reported to include lack of time, need for special equipment, provider knowledge, and perceived value of information.^6–8 Concerns have also been raised about the validity of patient- and clinician-reported outcomes and the potential need for stronger theory-referenced measurement tools.⁹

METHODOLOGY OF OUTCOMES MEASUREMENT

Outcome measures may be collected through a variety of ways, for example, self-reported answers to standardized questions, direct observation of performance, equipment recordings, or review of medical records. Outcome measures have the potential to be influenced by both the patient's and clinician's motivation and judgement.¹⁰ To provide useful information, all measures should have adequate reliability and validity documented with a sufficient sample size for a specific population.¹¹

Reliability of a measure indicates the degree of consistency with repeated measurements, with as little error or variation as possible.¹² All measurements have potential for error, from the individual taking the measurement to the measurement tool itself. The degree of variability of the characteristic being measured can also be a source of variation. For example, the reliability of pain measures may be difficult to determine because pain can fluctuate between measurement sessions due to ...