Can phase angle measurement with bioelectrical impedance analysis predict malnutrition, sarcopenia and frailty in elderly?

Objective: The world population is getting older and 9.1% of Turkey's population as of 2019 is formed by the elderly. Malnutrition, sarcopenia and frailty increase morbidity and mortality in the elderly. In this study, it is aimed to determine whether the phase angle calculated by bioelectrical impedance analysis can predict malnutrition, sarcopenia and frailty in elderly. Materyal and Methods: 206 patients aged 65 and over were included in the study, between July 2019 and December 2019. The patients were taken from Gülşehir district of Nevşehir and from Istanbul Medical Faculty Geriatrics and Clinical Nutrition Outpatient Clinics. The demographic characteristics of the patients, whether they have ever fallen, walked with or without support, and known chronic diseases were questioned; with the short form of the mini nutritional assessment, malnutrition risks, with the "Frail" scale, the state of fragility was determined. Body mass indexes were calculated by measuring the height and weight of the patients. Hand grip strength was measured with the hand dynamometer, walking speeds were calculated with the 4-meter walking test, muscle mass and phase angle was measured with bioelectrical impedance analysis. The cut-off value for the phase angle is taken as 5⁰. Its effect level was investigated by univariate and multivariate logistic regression. Patients with malnutrition, sarcopenic and frail patients were identified and their relationship with phase angles were analyzed. Results: Of these 206 patients, 47.6% (n=98) were female and 52.4% (n=108) were male. The mean age of the patients was 72.6 ± 6.3 years, mean BMI was 29.3±6.1 kg/m2. 18% (n = 37) of the patients had a risk of malnutrition and %50 of the patients' (n=103) muscle strength was low. The mean appendicular muscle mass (ASM) measured by BIA was 21.6±4.3 kg and ASM was found low in 10.7% (n=22). The ASM index (ASMI) average was calculated as 8.3±1.3 kg/m2 and was low in 6.3% (n=13) of the patients. With these results, muscle strength and muscle mass were low in 11 patients (5.3%) (EWGSOP2, definitive sarcopenia). 34% of the patients' (n=70) walking speed was low (≤0.8 m/s) and 17% (n = 35) were fragile according to the Frail criteria. 37 patients (18%) had a history of falling at least once in the past year. The phase angle measurement was low (≤5⁰ ) in 42.2% of the patients (n = 87), and a significant correlation was found between low phase angle and malnutrition, sarcopenia and fragility (p<0.05). In the mutiple regression analysis, a significant relation was found between phase angle and muscle mass and walking speed according to age, gender, ASMI. Conclusion: Phase angle measurement with BIA in elderly predicts sarcopenia due to it can show low muscle weight and muscle function and can be used to diagnose sarcopenia.