ASK THE EXPERT - Scales

Q: Would scales that weigh total weight and percentage of body fat help us to pick up congestive heart failure (CHF) or other medical symptoms any easier, or be helpful in nursing homes?
Allen B. Jackson, MD

Larry E. Johnson, MD, PhD, Medical Director, Community Living Center/Nursing Home Care Unit, Central Arkansas Veterans Healthcare System, and Associate Professor of Geriatrics, and Family and Preventive Medicine, University of Arkansas for Medical Sciences, Little Rock, responds:

A: The short answer is “probably not.”

The long answer is:
My skepticism regarding body fat scales was not diminished by reviewing the 2004 Consumer Reports review, which documented relatively poor function. There is no way independently to ensure their accuracy or reliability, and it is unlikely that they have been validated in frail older adults with muscle/fat/water content different from younger adults. Their small size would make them impossible to use for frail older adults with any balance problems. Fat percentage may also not have much predictive value in frail older adults. Fat location appears to better predict future health outcomes in younger adults. That is, fat located in buttocks and thighs appears to have less adverse metabolic and cardiovascular risks than fat located in and around the abdomen. In addition, some fat stores (but what amount is not yet certain) may have protective value in frail older adults, both as padding in falls and as an energy reserve during illness.

Accuracy, reliability, and consistency of weight measurements are a constant challenge in the nursing home. There are many reasons for this: (1) poor training and low motivation and lack of positive reinforcement with the nursing home aides; (2) scales that lose accuracy over time and are not regularly calibrated; (3) different staff weigh patients using different scales (eg, bed scales, standing scales, lift scales) wearing different clothing at different times of the day, in and out of their wheelchairs, holding on to poles or aides for balance, before and after dialysis or diuretics, with and without their casts, braces, shoes, etc.

Despite all of the above difficulties in obtaining and interpreting weights of nursing home residents, following weight change still remains the best way to detect undernutrition. Malpractice lawyers also like to use documentation of weight loss (without an adequate response by staff, dietitians, and physicians) as a marker for poor care. A weight loss of 5% or more in 1 month, 7% in 3 months, or 10% in 6 months, must be recognized by the nursing, dietary, and medical staff, and have a detailed assessment and treatment plan, with regular updates and with new interventions tried if the patient continues to lose weight, thoroughly documented in the nursing home chart.

The studies that find daily weight measurements as helpful in managing CHF in younger outpatients have not been replicated in frail nursing home residents. In the vast majority of nursing home settings, it is unrealistic to expect accurate daily weights by overworked nursing home employees, AND to have that communicated efficiently to the healthcare providers, AND to receive a timely response from the healthcare provider. Daily weighing MIGHT be helpful in the home setting with trained and motivated family members using a standardized technique who then have a diuretic protocol. The use of home telemedicine monitors regularly reviewed by trained nurses has promise.

Sources

Liu L, Bopp MM, Roberson PK, Sullivan DH. Undernutrition and risk of mortality in elderly patients within 1 year of hospital discharge. J Gerontol A Biol Sci Med Sci 2002;57:M741-M746.

Sullivan DH, Johnson LE, Bopp MM, et al. Prognostic significance of monthly weight fluctuations among older nursing home residents. J Gerontol A Biol Sci Med Sci 2004;59:M633-M639.

Sullivan DH, Liu L, Roberson PK, Bopp MM, Rees JC. Body weight change and mortality in a cohort of elderly patients recently discharged from the hospital. J Am Geriatr Soc 2004;52: 1696-1701.