Table 4.
Multi-step multivariable linear regression analyses for harmonized serum phosphate levels
| Model 1 | Model 2 | Model 3 | Model 4 | ||
|---|---|---|---|---|---|
| Difference between CRIC and CKD-JAC at each eGFR category [vs CKD-JAC]* | [≤20] | 0.98 (0.85, 1.11) | 0.89 (0.77, 1.03) | 0.87 (0.73, 1.00) | 0.74 (0.60, 0.88) |
| [21 - 30] | 0.77 (0.70, 0.84) | 0.68 (0.61, 0.76) | 0.67 (0.59, 0.74) | 0.62 (0.55, 0.70) | |
| [31 - 40] | 0.63 (0.56, 0.70) | 0.55 (0.47, 0.62) | 0.52 (0.45, 0.59) | 0.53 (0.46, 0.61) | |
| [41 - 50] | 0.53 (0.46, 0.61) | 0.45 (0.37, 0.53) | 0.42 (0.34, 0.50) | 0.46 (0.38, 0.54) | |
| [>50] | 0.48 (0.37, 0.60) | 0.37 (0.25, 0.49) | 0.34 (0.22, 0.46) | 0.42 (0.30, 0.54) | |
| eGFR | [≤20] | 0.49 (0.38, 0.60) | 0.48 (0.37, 0.59) | 0.49 (0.37, 0.60) | 0.62 (0.50, 0.74) |
| [21 - 30] | 0.15 (0.04, 0.26) | 0.14 (0.03, 0.25) | 0.14 (0.02, 0.25) | 0.22 (0.11, 0.34) | |
| [31 - 40] | 0.06 (−0.05, 0.17) | 0.05 (−0.06, 0.16) | 0.05 (−0.06, 0.16) | 0.10 (−0.01, 0.21) | |
| [41 - 50] | 0.03 (−0.08, 0.15) | 0.01 (−0.10, 0.13) | 0.01 (−0.10, 0.13) | 0.05 (−0.07, 0.17) | |
| [>50] | Ref. | Ref. | Ref. | Ref. | |
| Phosphate binders | [yes] | 0.06 (0.00, 0.12) | 0.08 (0.02, 0.13) | 0.06 (−0.00, 0.12) | 0.06 (0.01, 0.12) |
| Active vitamin D | [yes] | 0.03 (−0.03, 0.09) | 0.03 (−0.03, 0.09) | 0.00 (−0.06, 0.06) | 0.00 (−0.06, 0.06) |
| log(25OHD) | (/S.D.) | −0.01 (−0.03, 0.01) | −0.02 (−0.03, 0.00) | −0.03 (−0.04, −0.01) | −0.03 (−0.04, −0.00) |
| log(DHQ calcium) | (/S.D.) | 0.03 (0.01, 0.05) | 0.03 (0.01, 0.05) | 0.03 (0.01, 0.05) | |
| log(uPhos/uCr) | (/S.D.) | 0.08 (0.06, 0.09) | 0.07 (0.06, 0.09) | −0.01 (−0.04, 0.03) | |
| log(uPhos/uCr) x eGFR | [≤20] | 0.27 (0.21, 0.33) | |||
| [21 - 30] | 0.13 (0.09, 0.18) | ||||
| [31 - 40] | 0.06 (0.02, 0.11) | ||||
| [41 - 50] | 0.03(−0.01, 0.08) | ||||
| [>50] | Ref. | ||||
| log(PTH) | (/S.D.) | −0.05 (−0.07, −0.03) | −0.06 (−0.07, −0.04) | ||
| log(intact FGF23) | (/S.D.) | 0.06 (0.03, 0.08) | 0.05 (0.03, 0.08) |
There was a significant interaction between CRIC x eGFR in every model.
Data are expressed as mean (95% confidence interval). Abbreviations: eGFR, estimated glomerular filtration rate; 25OHD, 25-hydroxyvitamin D; DHQ, dietary health questionnaire; uPhos/uCr, urine phosphate-to-creatinine ratio; PTH, parathyroid hormone; FGF23, fibroblast growth factor-23; S.D., standard deviation. Bold values denote statistical significance of p < 0.05.
Model 1: Adjusted for demographics (age, gender, urine albumin-to-creatinine ratio, diabetes, and facilities as cluster) + Nutrition (albumin and body mass index category) + Medication (active vitamin D and phosphate binders) + 25OHD
Model 2: Model 1 + calcium intake (DHQ calcium) + phosphorus intake (DHQ phosphorus + pops frequency (3a) or uPhos/uCr (3b))
Model 3: Model 2 + PTH + FGF23
Model 4: Model 3 + interaction term of uPhos/uCr x eGFR