Multifrequency bioelectrical impedance analysis may represent a reproducible and practical tool to assess skeletal muscle mass in euvolemic acutely ill hospitalized geriatric patients

Key summary pointsAim To study the reproducibility of skeletal muscle mass assessment using multifrequency bio-impedance analysis in acutely ill hospitalized geriatric patients. Findings Mean coefficient of variation of the three skeletal muscle mass measurements was 4.9% with excellent test-retest reliability. However, non-euvolemic patients showed a significantly larger variation and significantly lower test-retest reliability when compared to the euvolemic patients in this pilot study. Message Multifrequency bio-impedance analysis seems a reliable method to assess skeletal muscle mass during the first week of hospitalization in geriatric patients, however, clinicians should be aware that in patients with over- or dehydration measurements may better take place after hydration status is normalized.

Purpose Geriatric patients with low skeletal muscle mass (SMM) and strength have a poor clinical outcome following acute illness. Consequently, it is recommended to assess SMM and strength in patients admitted to the acute care geriatric ward. Bio-impedance analysis (BIA) is a practical tool to assess SMM in hospitalized patients. However, the reproducibility of this assessment may be compromised due to changing clinical conditions. The objective was to study the reproducibility of SMM assessment using multifrequency BIA (mf-BIA) in acutely ill geriatric patients. Methods A total of 47 geriatric patients (age: 83 +/- 7 years; n = 31 female) admitted to the acute geriatric ward participated in this pilot study. SMM was assessed on three occasions within the first week of hospital admission using the Maltron Bioscan-920-II. Results Total skeletal SMM averaged 21.4 +/- 5.7, 20.7 +/- 5.4, and 20.8 +/- 5.1 kg assessed at 2 +/- 1, 3 +/- 1 and 5 +/- 2 days after hospital admission, respectively. Coefficient of variation (COV) of the three SMM measurements was 4.9 +/- 4.5% with an intraclass correlation coefficient (ICC) of 0.976 (CI 95%: 0.961-0.986; P <0.001). Hydration status affected the reproducibility of the measurement, with non-euvolemic patients (n = 16) showing a significantly higher COV (7.6 +/- 5.9% vs 3.5 +/- 2.9%; P <0.01) and a lower ICC (0.983 vs 0.913; P <0.001) when compared to the euvolemic patients (n = 31). Conclusion Mf-BIA seems a highly reproducible and reliable method to assess SMM throughout the first week of hospitalization in geriatric patients. However, since abnormal hydration status may compromise reliability of the measurement, assessment of SMM using mf-BIA may better be performed when euvolemic status has been established.