Table 1.
Participant characteristics before and after the exclusion of participants with discrepant values of mGFR
| MDRD Study | AASK | MDRD Study + AASK | ||||
|---|---|---|---|---|---|---|
| All mGFRs | Consistent* mGFRs |
All mGFRs | Consistent* mGFRs |
All mGFRs | Consistent* mGFRs |
|
| Sample Size (no. participants) | 1046 | 906 | 949 | 840 | 1995 | 1746 |
| Female (%) | 39% | 39% | 39% | 39% | 39% | 39% |
| Age, years | 52 +/− 13 | 52 +/− 12 | 55 +/− 11 | 54 +/− 11‡ | 53(12 | 53 +/− 12 |
| Black | 10% | 10% | 100% | 100% | 53% | 53% |
| Diabetes | 6% | 6% | 0% | 0% | 3% | 3% |
| Height, cm | 171 +/− 10 | 171 +/− 10 | 171 +/− 10 | 171 +/− 10 | 171 +/− 10 | 171 +/− 10 |
| Weight, kg | 79 +/− 16 | 79 +/− 16 | 90 +/− 21 | 90 +/− 21 | 84 +/− 19 | 84 +/− 19 |
| Body Mass Index, kg/m2 | 27 +/− 4 | 27 +/− 4 | 31 +/− 7 | 31 +/− 7 | 29 +/− 6 | 29 +/− 6 |
| Body Surface Area, m2 | 1.9 +/− 0.2 | 1.9 +/− 0.2 | 2.0 +/− 0.2 | 2.0 +/− 0.2 | 2.0 +/− 0.2 | 2.0 +/− 0.2 |
| Serum Cystatin, mg/L | 2.2 +/− 0.8 | 2.2 +/− 0.7‡ | 1.7 +/− 0.6 | 1.7 +/− 0.6 | 2.0 +/− 0.7 | 2.0 +/− 0.7‡ |
| Serum Creatinine, mg/dL | 2.5 +/− 1.1 | 2.4 +/− 1.0‡ | 2.0 +/− 0.7 | 2.0 +/− 0.7 | 2.3 +/− 1.00 | 2.2 +/− 0.9‡ |
| mGFR | ||||||
| Reference (5th-95th %ile) | 33 +/− 14 (13- 57) |
34 +/− 14‡ (14-57) | 46 +/− 13 (24- 64) |
46 +/− 13‡ (24-64) | 39 +/− 15 (15- 63) |
40 +/− 15‡ (16-63) |
| Other pre-randomization visit (5th-95th %ile) | 34 +/− 13† (14- 56) |
34 +/− 13‡ (14-56) | 47 +/− 15† (23- 72) |
46 +/− 14‡ (23-67) | 40 +/− 16† (16-66) |
40 +/− 15† (17-65) |
| Difference from reference mGFR | 0.7 +/− 5.4 | 0.1 +/− 3.9‡ | 1.4 +/− 7.8 | 0.3 +/− 5.1‡ | 1.0 +/− 6.7 | 0.2 +/− 4.5‡ |
| % Difference from reference mGFR | 5.6 +/− 19.8 | 1.8 +/− 10.9‡ | 3.3 +/− 17.8 | 0.5 +/− 11.0‡ | 4.5 +/− 18.9 | 1.2 +/− 11.0‡ |
| Time between mGFR visits, days | 104 +/− 19 | 104 +/− 19 | 15 +/− 8 | 15 +/− 8 | 62 +/− 19 | 61 +/− 47 |
| Subgroup with 3rd mGFR (post randomization) | ||||||
| No. | 764 | 632 | 504 | 341 | 1268 | 973 |
| Third mGFR (5th-95th %ile) | 31 +/− 12† (13- 51) |
32 +/− 12 †‡ (14- 52) |
46 +/− 17 (20- 74) |
45 +/− 14† (22-68) | 37 +/− 16† (14-66) |
37 +/− 14† (15-61) |
| Difference from reference mGFR | −1.3 +/− 4.5 | −1.1 +/− 10.2‡ | 0.2 +/− 11.1 | −0.7 +/− 5.9‡ | −0.7 +/− 7.9 | −1.0 +/− 4.5‡ |
| % Difference from reference mGFR | −4.2 +/− 13.9 | −3.7 +/− 10.2‡ | 0.7 +/− 26.0 | −1.9 +/− 12.4‡ | −2.2 +/− 20 | −3.0 +/− 11.0‡ |
| Time between reference and 3rd mGFR, days | 65 +/− 9 | 65 +/− 9 | 134 +/− 9 | 134 +/− 9 | 93 +/− 35 | 89 +/− 34‡ |
Note: Mean +/− SD reported for continuous data. Units of GFR are mL/min/1.73m2. Conversion factors for units: serum creatinine in mg/dL to μmol/L, X88.4; serum cystatin C in mg/L to nmol/L, X74.9; GFR in mL/min/1.73m2 to mL/s/1.73m2 × 0.01667
*
mGFR is ≤ 25% different from the reference mGFR
†
p< 0.05 in a paired t-test compared to the reference mGFR
‡
t-test comparing consistent to inconsistent mGFRs p < 0.05
Abbreviations: MDRD, Modification of Diet in renal Disease Study; AASK, African American Study of Kidney Disease; mGFR, measured glomerular filtration rate.