Bioimpedance phase angle as a marker of sarcopenia in elderly women with multiple comorbidities

Rationale: The progressive decline in skeletal muscle strength and function during aging can lead to disability and premature death. It is of interest to evaluate the potential of bioimpedance phase angle (PhA) as an instrumental marker of sarcopenia in clinical practice.

Aim: To identify an association between the phase angles determined by the bioimpedance analysis of body composition, with functional activity parameters in elderly women with multiple comorbidities.

Materials and methods: The study included 146 elderly women (aged 75 to 84 years, mean age 79.44 ± 2.56 years). Assessments consisted of the Charlson comorbidity index, “Vozrast ne pomekha” (Age is not a hindrance) questionnaire, the Barthel index, the sit-to-stand five-repeat test, the standardized 4-meter walking speed test, and bioimpedance analysis of body composition (ABC-02, Medass, Russia). Muscle strength parameters were assessed by wrist dynamometry with a mechanical wrist dynamometer. The hand dynamometry index was calculated by dividing the hand grip strength by the patient's squared height. According to the EWGSOP2 guidelines for the critical cur-off for hand dynamometry, the patients were divided into two groups: those with the hand grip strength > 16 kg (n = 41) and those with < 16 kg (n = 105).

Results: There were significant correlations of PhA with age (r = -0.369; p =0.017), the results of the screening questionnaire “Vozrast ne pome-kha” (Age is not a hindrance) (r = -0.359; p = 0.023), Barthel index (r = 0.375; p = 0.018), hand dynamometry (r = 0.395; p = 0.014), hand dynamometry index (r = 0.340; p = 0.021), lean body mass (r = 0.414; p = 0.009), musculoskeletal mass (r = 0.819; p < 0.001), proportion of musculoskeletal mass (r = 0.796; p < 0.001), walking speed (r = 0.670; p < 0.001), and the results of the sit-to-stand test (r = -0.541; p < 0.001). Sarcopenia was diagnosed in 61 women (41.8%). There were also significant differences in age, hand dynamometry results, hand dynamometry index, walking speed and results of the sit-to-stand test between the two groups depending on their hand grip strength.

Conclusion: The use of hand dynamometry, physical activity tests, and bioimpedance phase angle can be used in clinical practice to diagnose sarcopenia.