Table 2.
Statistics of BIS vs SFBIA data in non-CKD BMI stratified subgroup
| Underweight subjects (n=40) | ||||||||
|---|---|---|---|---|---|---|---|---|
| Bland-Altman | ||||||||
| 95% limits of agreement | ||||||||
| Data analysed | BIS | SFBIA | ICC | r | Biasa (%)b | 95%CI Biasc (%)d | Lower | Upper |
| R (ohm) | 848±74 | 596±103 | -0.02 | -0.12 | 252+134 (35.5+18.9) | 209 to 294 (29 to 42) | -10 | 513 |
| Xc (ohm) | 86±9.3 | 63±9.5 | -0.03 | -0.12 | 23+14 (31.1+18.1) | 19 to 28 (25 to 37) | -4.6 | 51 |
| PA (ₒ) | 5.8±0.5 | 6.1±0.6 | 0.12 | 0.09 | -0.3+0.8 (-4.8+12.6) | -0.5 to -0.05 (-8.9 to -0.7) | -1.8 | 1.2 |
| TBW (L) | 27±3.9 | 30±4.1 | 0.38** | 0.47** | -3.4+4.1 (-11.7+14.3) | -4.7 to -2 (-16 to -7.1) | -11 | 4.7 |
| ECW (L) | 11±1.4 | 14±2.2 | 0.20* | 0.47** | -2.9+2 (-22.8+14.8) | -3.6 to -2.3 (-28 to -18) | -6.8 | 0.9 |
| ICW (L) | 16±2.6 | 16±1.9 | 0.45** | 0.44** | -0.4+2.5 (-3.1+14.8) | -1.2 to 0.4 (-7.9 to 1.7) | -5.2 | 4.4 |
| FFM (kg) | 34±6.3 | 43±4.8 | 0.26* | 0.59** | -9.1+5.1 (-24.4+13.9) | -11 to -7.5 (-29 to -20) | -19 | 1 |
| FM (kg) | 14±4 | 5±4.4 | 0.07* | 0.27* | 8.8+5.1 (81+202.4) | 7.2 to 10 (15 to 147) | -1.1 | 19 |
| Normal weight subjects (n=120) | ||||||||
| Bland-Altman | ||||||||
| 95% limits of agreement | ||||||||
| Data analysed | BIS | SFBIA | ICC | r | Biasa (%)b | 95%CI Biasc (%)d | Lower | Upper |
| R (ohm) | 718±99 | 621±97 | -0.02 | -0.05 | 97+141 (14.6+20.6) | 71 to 122 (11 to 18) | -180 | 374 |
| Xc (ohm) | 82±9.6 | 63±8.9 | 0.04 | 0.13 | 19+12 (25.8+16.9) | 16 to 21 (23 to 29) | -5.3 | 43 |
| PA (ₒ) | 6.6±0.8 | 5.9±0.5 | 0.10 | 0.17 | 0.7+0.9 (11.1+14.1) | 0.5 to 0.9 (8.6 to 14) | -1 | 2.5 |
| TBW (L) | 35±7.3 | 32±4.4 | 0.51** | 0.62** | 2.1+5.7 (4.9+16.7) | 1.0 to 3.1 (1.8 to 7.9) | -9.1 | 13 |
| ECW (L) | 14±2.6 | 16±2.4 | 0.58** | 0.66** | -1.3+2.1 (-9.4+14.3) | -1.7 to -0.9 (-12 to -6.8) | -5.4 | 2.7 |
| ICW (L) | 20±4.8 | 17±2 | 0.27* | 0.56** | 3.4+4 (16.2+19.4) | 2.7 to 4.1 (13 to 20) | -4.4 | 11 |
| FFM (kg) | 43±11 | 47±5.6 | 0.52** | 0.71*** | -3.6+8.5 (-10.9+20) | -5.2 to -2.1 (-15 to -7.2) | -20 | 13 |
| FM (kg) | 21±7.1 | 18±6.5 | 0.21* | 0.25* | 3.6+8.3 (18.8+50.4) | 2.1 to 5.1 (9.8 to 28) | -13 | 20 |
| Overweight subjects (n=118) | ||||||||
| Bland-Altman | ||||||||
| 95% limits of agreement | ||||||||
| Data analysed | BIS | SFBIA | ICC | r | Biasa (%)b | 95%CI Biasc (%)d | Lower | Upper |
| R (ohm) | 650±78 | 547±102 | 0.01 | 0.02 | 102±128 (18±22) | 79 to 126 (14 to 22) | -148 | 352 |
| Xc (ohm) | 77±9 | 62±8.3 | 0.01 | -0.02 | 15±12 (21±18) | 12 to 17 (18 to 24) | -9.6 | 39 |
| PA (ₒ) | 6.8±0.8 | 6.6±0.9 | 0.01 | 0.01 | 0.2±1.2 (3±18) | -0.03 to 0.4 (-0.4 to 6.3) | -2.2 | 2.6 |
| TBW (L) | 38±7.7 | 37±6 | 0.52** | 0.52** | 0.8±6.8 (1.4±18) | -0.4 to 2.1 (-1.8 to 4.7) | -13 | 14 |
| ECW (L) | 16±2.8 | 17±2.8 | 0.65** | 0.70*** | -0.9±2.2 (-6.1±13) | -1.4 to -0.6 (-8.4 to -3.7) | -5.2 | 3.3 |
| ICW (L) | 22±5.1 | 20±3.5 | 0.30** | 0.34** | 1.8±5.1 (7.4±23) | 0.9 to 2.8 (3.1 to 12) | -8.1 | 12 |
| FFM (kg) | 45±13 | 55±8.9 | 0.31** | 0.46** | -9.5±12 (-21±24) | -12 to -7.4 (-26 to -17) | -32 | 13 |
| FM (kg) | 34±9.2 | 24±5.7 | -0.07* | -0.13* | 9.6±11 (31±41) | 7.5 to 12 (24 to 39) | -13 | 32 |
| Obese subjects (n=108) | ||||||||
| Bland-Altman | ||||||||
| 95% limits of agreement | ||||||||
| Data analysed | BIS | SFBIA | ICC | r | Biasa (%)b | 95% CI Biasc (%)d | Lower | Upper |
| R (ohm) | 596±77 | 482±53 | 0.07 | 0.19 | 114±85 (20.8+14.8) | 98 to 130 (17.9 to 23.6) | -52 | 280 |
| Xc (ohm) | 71±9.3 | 61±6.9 | -0.01 | -0.01 | 9.8±12 (14.5+17.4) | 8 to 12 (11.2 to 17.9) | -13 | 33 |
| PA (ₒ) | 6.8±0.8 | 7.2±0.6 | 0.01 | -0.05 | -0.4±1 (-5.7+15.3) | -0.6 to -0.2 (-8.7 to -2.8) | -2.5 | 1.7 |
| TBW (L) | 42±8.2 | 42±5.4 | 0.70*** | 0.77*** | -0.6±5.4 (-2.4+12.5) | -1.6 to 0.4 (-4.8 to 0.01) | -11 | 9.9 |
| ECW (L) | 18±3.1 | 19±2.9 | 0.79*** | 0.82*** | -0.8±1.9 (-4.5+9.7) | -1.2 to -0.4 (-6.4 to -2.7) | -4.4 | 2.8 |
| ICW (L) | 24±5.3 | 23±2.4 | 0.53** | 0.69** | 0.2±4 (-0.9+16.6) | -0.5 to 1 (-4.1 to 2.3) | -7.6 | 8.1 |
| FFM (kg) | 46±12.9 | 64±8.1 | 0.26* | 0.71*** | -18±9.2 (-36.4+20.5) | -20 to -16 (-40.3 to -32.5) | -36 | -0.5 |
| FM (kg) | 52±11.5 | 33±6.7 | 0.16* | 0.61** | 19±9.1 (43.3+18.7) | 17.2 to 20.7 (39.7 to 46.9) | 1 | 37 |
BIS, multifrequency bioelectrical impedance spectroscopy; BMI, body mass index; ECW, extracellular water; FFM, fat free mass; FM, fat mass; ICC, Intraclass Correlation Coefficient; ICW, intracellular water; PA, phase angle; r, Pearson correlation coefficient; R, resistance; SFBIA, single-frequency bioelectrical impedance; TBW, total body water; Xc, reactance. Data presented as mean ± SD or minimum to maximum value. ICC, *p<0.05, **p<0.01 BIS vs SFBIA. r, *p<0.05, **p<0.01 BIS vs SFBIA. aMean error between BIS and SFBIA: BIS – SFBIA. bMean percentage error between BIS and SFBIA: Bias/[(BIS + SFBIA)/2] X 100. c95%CI of difference between BIS and SFBIA: BIS – SFBIA. d95%CI of difference between BIS and SFBIA (%): Bias/[(BIS + SFBIA)/2] X 100. 95%CI that include zero are unbiased.