Table 3.
Associations of uric acid with nutritional parameters and their rates of changes (slopes) over 36 months on the basis of a mixed effects model
| Variable | Uric Acid, mg/dl | Uric Acid × Time Interaction | ||
|---|---|---|---|---|
| Estimate (95% CI) | P Value | Estimate (95% CI) | P Value | |
| Dietary intake | ||||
| DEI, kcal/kg per d | −0.28 (−1.20 to 0.64) | 0.49 | 0.06 (−0.23 to 0.33) | 0.71 |
| DPI, g/kg per d | −0.13 (−3.23 to 2.97) | 0.93 | 0.06 (−0.49 to 0.60) | 0.84 |
| nPCR, g/kg per d | −0.02 (−0.05 to 0.02) | 0.35 | <0.01 (<−0.01 to 0.01) | 0.31 |
| Biochemical markers | ||||
| Albumin, g/L | −0.89 (−1.31 to −0.46) | <0.001 | 0.14 (0.06 to 0.21) | <0.001 |
| Transferrin, mg/dl | −0.06 (−0.09 to −0.02) | <0.001 | <0.01 (<0.01 to 0.01) | 0.03 |
| Creatinine, mg/dl | −0.37 (−0.56 to −0.18) | <0.001 | 0.07 (0.03 to 0.10) | <0.001 |
| Cholesterol, mg/dl | −5.37 (−9.86 to −0.88) | 0.02 | 0.73 (<0.01 to 1.51) | 0.04 |
| TG, mg/dl | −8.67 (−16.56 to −0.79) | 0.03 | 0.82 (<0.01 to 2.19) | 0.04 |
| CRP, mg/L | 0.17 (−3.91 to 4.24) | 0.94 | 0.21 (−0.50 to 0.92) | 0.56 |
| Anthropometric measurements | ||||
| BMI, kg/m2 | −0.61 (−0.83 to −0.38) | <0.001 | 0.07 (0.03 to 0.11) | 0.001 |
| TSF, mm | −1.18 (−1.82 to −0.55) | <0.001 | 0.12 (0.01 to 0.23) | 0.03 |
| MAC, cm | −0.54 (−0.94 to −0.15) | <0.01 | 0.03 (−0.04 to 0.10) | 0.45 |
| MAMC, cm | −0.17 (−0.54 to 0.20) | 0.37 | −0.01 (−0.07 to 0.05) | 0.76 |
All nutritional variables presented were modeled separately as dependent variables. Uric acid was included in these models as an independent variable together with fixed factors (such as age, sex, diabetes status, dialysis vintage, vascular access type, Kt/V, diuretic use, and comorbidity index). The models take into account every measurement of uric acid and present nutritional variables at each time point separately for each patient. Regression coefficients in column 2 indicate longitudinal associations of uric acid levels with nutritional markers at any given time point, while controlling for fixed factors (as mentioned above). Regression coefficients in column 3 indicate the rate of change in nutritional markers (slopes) over the study period by each 1-mg/dl increase in uric acid (uric acid by time interactions), controlling for the same fixed factors. 95% CI, 95% confidence interval; DEI, daily energy intake; DPI, daily protein intake; nPCR, normalized protein catabolic rate; TG, triglyceride; CRP, C-reactive protein; BMI, body mass index; TSF, triceps skinfold thickness; MAC, midarm circumference; MAMC, midarm muscle circumference calculated.