Table 2.
Levels of Anion Gap by Categories of CKD-EPI and Cystatin C-based eGFR in participants of NHANES 1999–2004
| Anion gap by CKD-EPI eGFR category in 11,957 participants | ||||||
|---|---|---|---|---|---|---|
| Traditional Anion Gap (mEq/L) | Albumin-adjusted Anion Gap (mEq/L) |
Full Anion Gap (mEq/L) | ||||
| Mean (SE) | Change | Mean (SE) | Change | Mean (SE) | Change | |
| eGFR | ||||||
| ≥ 120 (n=1330) | 12.05 (0.16) | −0.03 (−0.28 to 0.22) | 1.14 (0.16) | 0.005 (−0.25 to 0.26) | 5.24 (0.16) | −0.11 (−0.37 to 0.15) |
| 90 – 119 (n=5288) | 12.08 (0.17) | ref | 1.13 (0.17) | ref | 5.35 (0.17) | ref |
| 60 – 89 (n=4210) | 12.04 (0.15) | −0.04 (−0.17 to 0.10) | 1.20 (0.15) | 0.07 (−0.06 to 0.20) | 5.49 (0.16) | 0.14 (0.01 to 0.27) |
| 45 – 59 (n=792) | 12.21 (0.18) | 0.13 (−0.16 to 0.42) | 1.67 (0.17) | 0.54 (0.27 to 0.81) | 6.07 (0.18) | 0.72 (0.43 to 1.00) |
| 30 – 44 (n=259) | 12.65 (0.24) | 0.56 (0.28 to 0.85) | 2.29 (0.25) | 1.15 (0.87 to 1.43) | 6.78 (0.25) | 1.43 (1.15 to 1.70) |
| 15 – 29 (n=78) | 12.17 (0.26) | 0.09 (−0.46 to 0.63) | 2.02 (0.33) | 0.89 (0.25 to 1.53) | 6.55 (0.30) | 1.20 (0.63 to 1.76) |
| P trend* | 0.006 | <0.001 | <0.001 | |||
| <15 (n=24) | 16.02 (0.66) | 3.94 (2.66 to 5.23) | 5.53 (0.57) | 4.39 (3.26 to 5.53) | 9.20 (0.70) | 3.85 (2.49 to 5.21) |
| Anion gap by cystatin C eGFR category in 4,132 participants | ||||||
|---|---|---|---|---|---|---|
| Traditional Anion Gap (mEq/L) | Albumin-adjusted Anion Gap (mEq/L) |
Full Anion Gap (mEq/L) | ||||
| Mean (SE) | Change | Mean (SE) | Change | Mean (SE) | Change | |
| eGFR | ||||||
| ≥ 120 (n=307) | 12.81 (0.24) | 0.11 (−0.34 to 0.56) | 1.60 (0.26) | −0.04 (−0.48 to 0.39) | 5.86 (0.26) | −0.06 (−0.50 to 0.37) |
| 90 – 119 (n=1169) | 12.70 (0.23) | ref | 1.64 (0.23) | ref | 5.92 (0.24) | ref |
| 60 – 89 (n=1865) | 12.91 (0.24) | 0.21 (−0.04 to 0.46) | 2.08 (0.22) | 0.43 (0.20 to 0.67) | 6.39 (0.22) | 0.47 (0.21 to 0.72) |
| 45 – 59 (n=537) | 13.07 (0.36) | 0.37 (−0.22 to 0.95) | 2.47 (0.35) | 0.83 (0.30 to 1.35) | 6.82 (0.37) | 0.90 (0.33 to 1.46) |
| 30 – 44 (n=208) | 13.20 (0.23) | 0.50 (0.15 to 0.86) | 2.83 (0.25) | 1.19 (0.87 to 1.51) | 7.34 (0.24) | 1.42 (1.10 to 1.74) |
| 15 – 29 (n=52) | 13.67 (0.37) | 0.97 (0.28 to 1.67) | 3.24 (0.40) | 1.59 (0.85 to 2.34) | 7.72 (0.35) | 1.80 (1.17 to 2.42) |
| P trend* | 0.03 | <0.001 | <0.001 | |||
| <15 (n=15) | 17.36 (0.66) | 4.66 (3.29 to 6.02) | 6.69 (0.40) | 5.04 (4.14 to 5.95) | 10.90 (0.60) | 4.98 (3.73 to 6.23) |
Abbreviations: CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFR, estimated glomerular filtration rate; SE, standard error.
*
P values calculated without including participants with eGFR <15 mL/min/1.73m2 in the analysis.