Table 5.
Simple and multiple linear regression models for factors associated with bias in agreement between DXA and prediction equations in total sample.
| AFFMDXA—AFFMSergi (kg) | AFFMDXA—AFFMKyle (kg) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Simple linear regression model | Multiple linear regression model | Simple linear regression model | Multiple linear regression model | |||||||||||||
| Coefficient | 95% CI | p | Coefficient | 95% CI | p | Coefficient | 95% CI | p | Coefficient | 95% CI | p | |||||
| Lower | Upper | Lower | Upper | Lower | Upper | Lower | Upper | |||||||||
| Cross-sectional data (n = 266) | ||||||||||||||||
| Intercept | −0.443 | −0.738 | −0.148 | 0.003 | 0.775 | 0.491 | 1.060 | 0.000 | ||||||||
| Sex | 1.400 | 1.018 | 1.783 | 0.000 | −1.404 | −1.559 | −1.249 | 0.000 | 0.099 | −0.280 | 0.478 | 0.607 | −1.885 | −2.035 | −1.735 | 0.000 |
| RI (cm2/ohm) | 0.048 | 0.033 | 0.062 | 0.000 | −0.038 | −0.052 | −0.024 | 0.000 | −0.008 | −0.022 | 0.006 | 0.263 | −0.086 | −0.099 | −0.072 | 0.000 |
| TBW (L) | 0.096 | 1.018 | 1.783 | 0.000 | −0.328 | −0.363 | −0.294 | 0.000 | −0.002 | −0.027 | 0.023 | 0.856 | −0.322 | −0.355 | −0.288 | 0.000 |
| AFFM (kg) | 0.214 | 0.185 | 0.243 | 0.000 | 0.865 | 0.836 | 0.893 | 0.000 | 0.079 | 0.045 | 0.114 | 0.000 | 0.865 | 0.837 | 0.893 | 0.000 |
| FM (kg) | −0.042 | −0.067 | −0.018 | 0.001 | −0.077 | −0.084 | −0.070 | 0.000 | −0.047 | −0.069 | −0.025 | 0.000 | −0.074 | −0.080 | −0.068 | 0.000 |
| Body composition change (Δ) Data (n = 87) | ||||||||||||||||
| Intercept | 3.958 | 3.838 | 4.077 | 0.000 | 4.745 | 4.619 | 4.870 | 0.000 | ||||||||
| Sex | −1.384 | −2.062 | −0.705 | 0.000 | −1.368 | −1.522 | −1.215 | 0.000 | −1.874 | −2.616 | −1.131 | 0.000 | −1.881 | −2.042 | −1.720 | 0.000 |
| IR (cm2/ohm) | −0.073 | −0.125 | −0.022 | 0.006 | −0.076 | −0.107 | −0.440 | 0.000 | −0.121 | −0.176 | −0.065 | 0.000 | −0.125 | −0.158 | −0.091 | 0.000 |
| TBW (L) | −0.175 | −0.305 | −0.045 | 0.090 | −0.224 | −0.306 | −0.142 | 0.000 | −0.290 | −0.431 | −0.149 | 0.000 | −0.222 | −0.308 | −0.136 | 0.000 |
| AFFM (kg) | 0.661 | 0.481 | 0.841 | 0.000 | 0.846 | 0.777 | 0.914 | 0.000 | 0.580 | 0.349 | 0.811 | 0.000 | 0.842 | 0.770 | 0.913 | 0.000 |
| FM (kg) | −0.298 | −0.378 | −0.219 | 0.000 | −0.083 | −0.110 | −0.550 | 0.000 | −0.298 | −0.396 | −0.200 | 0.000 | −0.086 | −0.115 | −0.057 | 0.000 |
AFFM, appendicular fat free mass; DXA, dual energy X-ray absorptiometry; FM, fat mass; RI, resistance index; TBW, total body water. IR and TBW by bioelectrical impedance analysis. AFFM and FM by dual energy X-ray analysis. For regression model analysis, the following variables were evaluated: sex (1 man, 0 woman); age (years); estimated glomerular filtration ratio (mL/min/1.73 m2); KT/V; creatinine (mg/dL); urea (mg/dL); weight (kg), height (m); overhydration index (L); extracellular water (L); intracellular water (L); total body water (L); extracellular to total body water ratio; body cell mass (kg); lean mass, fat-free mass and fat mass by DXA analysis as well as their indexes; the variables present in this table.