L’impedenziometria può prevedere il peggioramento funzionale nell’anziano non autosufficiente ospite di strutture protette

Objectives. In elderly, sarcopenia is associated with disabilities, pressure sores falls and reduced physical performance. The aim of this study is to verify whether muscle mass, measured with bioelectrical impedance, is correlated to the risk of developing disability and functional deterioration. Methods. Observational prospective study in institutionalized elderly, with evaluation at baseline and after 4 months, by recording: physical examination, weight, height, BMI, bioelectrical impedance, Mini- Mental State Examination, Tinetti test and Braden scale. Skeletal muscle mass and skeletal muscle index (SMI) were obtained with bioelectrical impedance using the equation of Janssen. Statistical analysis was carried out using parametric or non-parametric statistics when appropriate, reciving operator curve and logistic regression. Results. We enrolled 191 subjects (F/M = 145/46), mean age 83 ± 10 years. Mean BMI was 22.5 ± 4.9 kg/m2. Mean SMI was significantly different in males and females (respectively 9.43 ± 1.39 and 7.53 ± 2.53 kg/m2, p < 0.001). In both genders, a value of SMI ≤ 7.7 kg/m2 was a predictor of loss of autonomous walking in the subsequent 4 months (sensitivity 90.6%, specificity 71.6%). In the multivariate analysis, SMI was the best predictor of loss of autonomous walking, while no significant relationship between SMI and other functional tests was found. SMI values <5 kg/m2 was associated to the development of pressure sores. Conclusions. Bioelectrical impedance is a simple and rapid technique to measure muscle mass in institutionalized elderly. SMI has a strong predictive power of loss of autonomous walking.