What patients value most: Measuring independence with the Barthel Index
For more than 60 years, the Barthel Index has helped researchers and clinicians assess something very important to patients: the ability to live independently. In this Q&A interview, Gene Ransom, CEO of MedChi, The Maryland State Medical Society, reflects on the measure's enduring relevance and its role in keeping real-world patient outcomes at the center of clinical research.
1. The Barthel Index has been used for more than 50 years to measure functional independence and recovery. What about this measure that has kept it relevant across generations of research and practice? What can today’s researchers learn from its longevity?
I think one of the reasons for the Barthel Index’s longevity is its relative simplicity and its focus on questions that have enduring clinical significance. Can an individual eat, dress, bathe, move, use the toilet, and perform other fundamental activities of daily living with independence? Those questions were important when the instrument was developed, and they remain important today.
There is also an interesting connection to MedChi, The Maryland State Medical Society. MedChi was founded in 1799 and is one of the oldest medical societies in the United States. The Barthel Index was formally published by Florence Mahoney and Dorothea Barthel in the Maryland State Medical Journal in 1965.
Its longevity offers an important lesson. Innovation in measurement does not always mean greater complexity. A measure can remain useful when it addresses a meaningful clinical concept, is practical to administer, and has accumulated evidence and experience across different settings. At the same time, longevity alone is not evidence of validity for every population or every research question. Researchers still need to determine whether a measure is appropriate for the particular population, intervention, and context in which it is being used.
2. The Barthel Index focuses on functional independence rather than only disease symptoms or clinical findings. Why is this distinction important when evaluating treatment benefit?
Clinical findings and disease-specific measures are essential, but they do not always tell us how a patient is actually functioning in daily life.
A treatment may produce a measurable change in a laboratory value, imaging result, or particular symptom. Those findings can be scientifically important. But physicians, patients, and families also want to understand whether that change translates into an ability to function more independently.
The Barthel Index looks at basic activities of daily living and the degree of assistance a person needs to perform them.
That provides a different and complementary perspective on treatment benefit. From my perspective at MedChi, good clinical research should ultimately help physicians and patients make better decisions. Functional information can help connect the scientific effect of an intervention with outcomes that are understandable and meaningful in everyday life.
We should be careful not to suggest that a single functional measure captures the complete patient experience. It does not. But when used appropriately alongside other clinical outcomes, functional measures can provide an important piece of overall evidence.
3. The Barthel Index was designed to understand whether patients can perform everyday activities independently. Why is measuring functional outcomes essential when evaluating the impact of new therapies?
Ultimately, one of the most important questions in medicine is not simply whether we can change a clinical measurement, but whether that change makes a meaningful difference in a person’s life.
Functional outcomes help us address that question.
For a person recovering from a stroke or living with another disabling condition, the ability to transfer from a bed, walk, dress, eat, or use the bathroom independently can profoundly affect quality of life. It can also affect caregivers, families, discharge planning, and the level of health care and social support that may be required.
The Barthel Index was specifically developed as a practical measure of independence in basic activities of daily living and has subsequently been used widely in rehabilitation and clinical research.
As new therapies are evaluated, functional outcomes can therefore help determine whether a clinical effect translates into a meaningful change in daily living. They should generally be considered as part of a broader evidence base, alongside safety, clinical endpoints, symptoms, and other outcomes relevant to the specific disease and patient population.
4. The Barthel Index has been recognized in regulatory contexts, including its inclusion in a labeling claim and referenced in health authority guidance documents. What does this recognition demonstrate about the value of well-established functional outcome measures in clinical development?
Regulatory recognition illustrates the potential value of a well-established outcome measure when there is sufficient evidence that it is appropriate for the specific context in which it is being used.
Regulators appropriately place considerable importance on how clinical outcome assessments are developed, validated, interpreted, and applied. FDA guidance, for example, emphasizes the need to evaluate an instrument and the evidence supporting its use when an outcome assessment is intended to support a medical product labeling claim.
An instrument such as the Barthel Index also benefits from decades of clinical and research experience. Researchers understand a great deal about how it performs, its strengths, and importantly, its limitations.
I would be cautious, however, about interpreting regulatory use as a universal endorsement of an instrument for every clinical trial. The appropriate measure depends upon the disease, population, treatment, endpoint, and intended claim.
The broader lesson is that well-established measures can be extremely valuable in clinical development when they are scientifically appropriate and used consistently and rigorously.
5. The collaboration between MRT and the Barthel Index community has spanned decades. How has this ongoing partnership supported the continued use, understanding, and appropriate application of the Barthel Index in clinical research?
Stewardship matters enormously for an instrument that is used internationally and across many different research settings.
The Maryland State Medical Society (MedChi), holds the copyright to the Barthel Index, while Mapi Research Trust has played an important role in its ongoing distribution and management. Mapi Research Trust maintains information regarding the original instrument, scoring, translations, electronic versions, permissions, and conditions of use.
That kind of stewardship helps preserve consistency. As an instrument becomes widely used, there is always the possibility that different versions, translations, scoring methods, or modifications can emerge. In fact, multiple modified versions of the Barthel Index have appeared over the years.
An ongoing partnership can help researchers identify the appropriate version, understand how it should be administered and scored, and maintain fidelity to the validated instrument.
From MedChi’s perspective, this also reflects something that has been central to our mission since our founding in 1799: promoting medical science and knowledge while maintaining appropriate standards. Good stewardship helps an important scientific resource remain accessible while protecting the integrity that made it valuable in the first place.
6. The Barthel Index measures something patients and families care deeply about: the ability to live independently and participate in daily life. What does the index’s continued use tell us about the importance of keeping patients’ real-world experiences at the center of clinical research?
It reminds us that medicine ultimately exists to improve people’s lives.
Scientific advances are extraordinarily important, and we need rigorous clinical endpoints to determine whether therapies are safe and effective. But patients and families often experience illness in very practical terms. Can I get out of bed? Can I walk? Can I dress myself? Can I eat independently? Will I need someone to help me with basic activities every day?
Those are not secondary concerns. They can be central to how a patient experiences recovery, disability, and quality of life.
The continued use of the Barthel Index reflects the importance of connecting clinical research to those real-world experiences. Its ten basic activities of daily living provide a structured way to assess aspects of independence that patients, families, physicians, and caregivers can readily understand.
At MedChi, we have represented Maryland physicians and promoted the health of Marylanders for more than two centuries. One principle that has endured throughout that history is that science and patient care must remain connected.
As research becomes more sophisticated, we should not lose sight of that. The best evidence helps us understand not only whether a therapy changes a biological or clinical endpoint, but what that change may mean for the person living with the disease.
Interested in measuring what matters most to patients? Reach out to Mapi Research Trust to discuss using the Barthel Index in your research.