Healthy aging: further research needed on measurement methods in geriatrics

Today’s society is faced with an aging population. The past has seen the development of many methods for measuring body composition in older adults. However, some of these techniques are not available to medical practices and hospital facilities or are in dire need of optimization.

In this MEDICA-tradefair.com interview, Professor Kristina Norman talks about different methods for measuring body composition, identifies their limitations and specifies where further research is needed.

Professor Norman, what is the current state of technology in body composition measurement in geriatrics? How do these techniques work?

Prof. Kristina Norman: That’s is not an easy question to answer since body composition includes different compartments and therefore several assessment methods. Experts can use diagnostic imaging techniques such as MRI and CT scans to measure muscle mass for example. They are considered the gold standard for muscle mass measurement because they are more accurate than indirect methods such as bioelectrical impedance analysis (BIA) for example. It is considered an indirect method because it only captures impedance, i.e., the effective resistance to alternating current, and subsequently measures the distribution of conductive tissue – tissue that is rich in water and electrolytes -, and non-conductive tissue such as body fat for example. A major challenge of BIA is to yield a valid and accurate percentage of muscle mass. We only measure resistance, put it in relation to body and weight and subsequently try to calculate the proportional percentage of muscle mass using statistical analysis and algorithms.

What practical problems or drawbacks are there when measuring the body composition in geriatrics?

Norman: All of the existing methods are applicable in clinical practice. The problem is that we are unable to use several methods in clinical practice because they are unavailable. Physicians at geriatrics specialty clinics don’t have routine secure access to CT scans or MRIs, and often not even to DEXA scans. Geriatric medicine resorts to simpler methods to ensure that as many patients as possible can be measured, even on a repeated basis. For example, BIA is a very attractive method in clinical practice. After all, it is non-invasive, relatively inexpensive and quick and can be repeated as often as needed. The drawback is that the method requires validation formulas to calculate the muscle mass in elderly subjects. There is an inadequate development of formulas that calculate muscle mass from resistance measurements in connection with other parameters such as body height and weight, age and gender etc. in older healthy persons. How would you then be able to accurately measure sick elderly subjects?

You refer to a whole-body MRI as an already existing validated method to measure body composition. However, it is not used due to high costs. What are the chances of this method becoming the routine measurement in the future? And if it doesn’t become the routine way, what techniques should be used as an alternative?

Norman: It is unlikely that MRIs will be routinely used as measurements in the future. They are simply too complex and costly. The benefit doesn’t outweigh the clinical costs and expenses, which we have to sadly keep down as much as possible. This would require a complex logistics structure that’s far too intricate. I prefer to rely on simple methods, such as BIA or ultrasound, which are less expensive but where further research and development is still needed to validate these techniques for older adults and thus improve implementation.

Bioelectrical impedance analysis is a commonly used technique of measuring the percentage of muscle mass in sick, elderly patients. However, the respective formulas are based on values of the younger and healthier population. That means they inadequately apply to the respective sick persons. That is why you call on professional associations to study the commonly used methods and validate them. How should clinical trials be set up to validate formulas?

Norman: I appeal to all researchers - and most notably to manufacturers - to develop formulas that allow conclusions about the muscle mass of older adults. You need a reference population that is as old as the study population if formulas are meant to be validated or developed. If you want to study people over the age of 80, it is expedient to have a reference population of the same age to validate the formulas. Having said that, you first need more reference values for the infirm elderly people.

What is your advice for geriatricians with regard to common analysis methods?

Norman: My advice or suggestion is to always consider what works best in your respective hospital facility. Most geriatricians are very skilled in functional assessments, including performance measurements and the assessment of strength, endurance, coordination, and balance. These types of tests are crucial. The parameters are important to assess how fit and capable the patient is in managing daily life. What’s more, they provide information that gives geriatricians a reference point to return patients to a healthy state again. Even if a hospital facility only has limited assessment methods at its disposal – if there is no ultrasound or BIA available, for example - simpler methods are still very essential and valuable. In these cases, it is crucial to monitor body weight and height on a regular basis. While this may sound trivial, it is often not done in clinical practice. Health professionals simply ask the patient or check once and then never again. That being said, if you have the chance to conduct a BIA, I suggest using age-specific formulas. However, we still lack a more honest approach to bioelectrical impedance analysis.  We need to raise awareness for the fact that BIA formulas are based on healthy, younger people and should not simply be applied as such to older adults. They often don’t provide an accurate or correct description of an older person’s body composition. However, BIA is generally an excellent method because it is non-invasive and delivers additional information apart from muscle mass. We urgently need more reference values, further research and the development of more age-specific formulas.