Table 1.
The characteristics of the study subjects
| CRIC | CKD-JAC | P-value | |
|---|---|---|---|
| # of subjects with serum phosphate measurement, N (% of original cohort) | 3870 (98.2) | 2632 (88.4) | NA |
| Age, years old | 58.2 ± 11.0 | 60.5 ± 11.5 | <0.001 |
| Male, N (%) | 2130 (55.0) | 1637 (62.2) | <0.001c |
| Race/Ethnicity, N (%) | |||
| White | 1611 (42) | - | NA |
| Black | 1617 (42) | - | |
| Hispanic | 498 (13) | - | |
| Asian | 106 (3) | 2632 (100) | |
| Others | 45 (1) | - | |
| eGFR, mL/min/1.73m2 | 42.8 ± 13.5 | 28.4 ± 12.3 | <0.001 |
| uACR, mg/gCr | 52 [9 - 457] | 497 [121 - 1332] | <0.001w |
| Diabetes, N (%) | 1877 (48.5) | 811 (31.2) | <0.001c |
| BMI, kg/m2 | 32.1 ± 7.8 | 23.5 ± 3.8 | <0.001 |
| BMI category, N (%)*1 | |||
| Underweight | 28 (0.7) | 174 (7.3) | <0.001c |
| Normal | 567 (14.7) | 987 (41.6) | |
| Overweight | 1083 (28.1) | 487 (20.5) | |
| Obese I | 1031 (26.7) | 590 (24.9) | |
| Obese II or more | 1152 (29.8) | 134 (5.7) | |
| Alb, mg/dL | 3.9 ± 0.5 | 4.0 ± 0.4 | 0.004 |
| Corrected Ca, mg/dL*2 | 9.4 ± 0.5 | 9.2 ± 0.5 | <0.001 |
| Phosphate binders, N (%) | 257 (6.7) | 94 (3.6) | <0.001c |
| Active vitamin D, N (%) | 122 (3.2) | 240 (9.2) | <0.001c |
| Native vitamin D, N (%) | 390 (10.1) | NA*3 | NA |
| Calcium intake by DHQ, mg/day | 618 [423 - 870] | 334 [229 - 464] | <0.001w |
| Phosphorus intake by DHQ, mg/day | 1060 [756 - 1436] | 744 [563 - 960] | <0.001w |
| Carbonated beverage intake, N (%) | |||
| <1 drink/week | 777 (26.8) | 1111 (62.4) | <0.001c |
| 1-6 drinks/week | 1001 (34.7) | 532 (30.1) | |
| 1-3 drinks/day | 925 (32.0) | 119 (6.8) | |
| 4 drinks or more/day | 191 (6.5) | 14 (0.7) | |
| uPhos/uCr, g/gCr | 0.57 [0.44 - 0.73] | 0.41 [0.30 - 0.52] | <0.001w |
Data are expressed as mean ± S.D. or median [interquartile range]. A superscript of “c” and “w” stand for χ2 test and Wilcoxon rank-sum test, respectively; t-test was performed unless otherwise noted. Abbreviations: NA, not available, BMI, body mass index; eGFR, estimated glomerular filtration rate; uACR, urine albumin-to-creatinine ratio; Alb, serum albumin; Ca, calcium; DHQ, dietary health questionnaire; uPhos/uCr, urine phosphate-to-creatinine ratio.
*1
WPRO criteria[27] for Asians, otherwise WHO criteria[28] were applied for classification of obesity.
*2
Corrected Ca = Ca + (4 - Alb) if Alb < 4.0.
*3
Native vitamin D is not available in Japan.