Table 2.
Relation of eGFR to traditional, albumin-corrected, and full anion gap in United States adults
| Traditional Anion Gap |
Albumin-Corrected Anion Gap |
Full Anion Gap |
||||
|---|---|---|---|---|---|---|
| Model | β (95% CI)* | P value | β (95% CI)* | P value | β (95% CI)* | P value |
| Unadjusted | ||||||
| Preserved (eGFR ≥ 60 ml·min−1·1.73 m−2) | Reference† | Reference† | Reference† | |||
| Moderate (eGFR: 30–59 ml·min−1·1.73 m−2) | 0.30 (0.008, 0.59) | 0.04 | 0.70 (0.39, 0.99) | <0.0001 | 0.79 (0.47, 1.11) | <0.0001 |
| Low (eGFR: 15–29 ml·min−1·1.73 m−2) | 1.64 (0.39, 2.89) | 0.01 | 2.42 (1.26, 3.56) | 0.0004 | 2.75 (1.61, 3.89) | <0.0001 |
| Trend | 0.01 | <0.0001 | <0.0001 | |||
| Adjusted | ||||||
| Preserved (eGFR: ≥60 ml·min−1·1.73 m−2) | Reference‡ | Reference‡ | Reference‡ | |||
| Moderate (eGFR: 30–59 ml·min−1·1.73 m−2) | 0.35 (0.08, 0.62) | 0.01 | 0.18 (−0.09, 0.45) | 0.19 | 0.26 (−0.02, 0.54) | 0.07 |
| Low (eGFR: 15–29 ml·min−1·1.73 m−2) | 1.54 (0.30, 2.78) | 0.01 | 1.47 (0.30, 2.64) | 0.01 | 1.73 (0.57, 2.89) | 0.004 |
| Trend | 0.007 | 0.07 | 0.02 | |||
All analyses included the total third National Health and Nutrition Evaluation Survey (NHANES III) mobile examination center-examined sample final weight to account for the complex sample design following the analytical guidelines for NHANES III data (32). For variance estimates, we used Fay’s balanced repeated replication procedure, an approach for estimation of standard errors for multistage samples that consists of many sampling units adjusted for demographics (age, sex, and race/ethnicity), education history, poverty income ratio, diabetes, and hypertension. Hypertension was defined as self-reported, average blood pressure > 140/90 mmHg, or use of medications. Diabetes was defined as self-reported or hemoglobin A1c ≥ 6.5%. eGFR, estimated glomerular filtration rate; CI, confidence interval. *From multivariable linear regression analysis. †See Fig. 1A.‡See Fig. 1B.