Repeatability and reproducibility of a BIA consumer device in measuring of muscle mass of geriatric inpatients

Objective To investigate the repeatability and reproducibility of a bioelectrical impedance analysis (BIA ) consumer device in measuring of appendicular skeletal muscle mass of geriatric inpatients. Methods A total of 50 inpatients were measured by a BIA consumer device by two trained researchers.Each researcher measured two times randomly.Data of appendicular skeletal muscle mass were extracted.Double factor variance analysis was used to evaluate the factors influencing measurement difference.Repeatability and reproducibility limits were applied to evaluate the measurement difference in repeated and reproduced conditions.Intra-class correlation coefficient(ICC), within-subject standard deviation(Sw)and repeatability coefficient(2.77Sw)were used to assess the repeatability of two researchers.Paired t test and Bland-Altman analysis were used to assess the agreement between two researchers. Results Variance analysis showed individual variance in objects themselves accounted for over 99% overall standard deviation.Repeatability and reproducibility limits were 0.64 and 0.65 respectively.ICCs were greater than 0.99.Paired t test showed no statistical difference between two researchers and Bland-Altman analysis showed mean difference were 0.02, 95% limits of agreements(LoA)were(-0.36, 0.33). Conclusion BIA device has high repeatability and reproducibility in measuring appendicular skeletal muscle mass of elderly inpatients. Key words: Repeatability; Reproducibility; Muscle mass; Nursing for the aged; Electrical bioimpedance