Knee-height as a reliable alternative measure for nutritional assessment in older adults

Objective:

To evaluate the use of knee-height as a reliable alternative measure for nutritional evaluation in older adults in a geriatrics outpatient clinic.

Methods:

Cross-sectional study with elderly patients being treated in a geriatrics outpatient clinic of a University Hospital between November 2009 and November 2010. Variables investigated: gender, age, weight, stature, kneeheight, estimated stature using Chumlea equations, body mass index based on measured and estimated stature and classified according to Lipschitz, and socio-demographic characteristics. Measures of central tendency, dispersion, and proportion were used in the descriptive data analysis. Homogeneity between these measures was verified using intraclass correlation coefficient and Bland and Altman plot, and the correlation between the nutritional assessment concerning the body mass index calculated based on the measured stature and the nutritional assessment calculated based on the estimated stature was established using the quadratic weighted Kappa coefficient.

Results:

One hundred eight-six elderly patients with average age of 74.3±7.1 years were evaluated. The average body mass index calculated and estimated were, respectively, 28.96±5.86 kgm², 27.95±5.47 kgm², and the prevalence of overweight was 59.7% for body mass index calculated and 53.2% for body mass index estimated. A good agreement between the evaluations was observed (Kappa=0.79; p<0.001).

Conclusion:

Results showed that it is possible to use the knee-height for the estimation of stature to determine the body mass index in elderly patients in a geriatric outpatient clinic. It proved a useful alternative especially when it is difficult to obtain accurate measures in older adults, suggesting that knee-height is an important alternative measure for the nutritional status evaluation in elderly patients.

Anthropometry; Nutritional assessment; Body height; Aged; Estimation techniques