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.