Table 2.
Accuracy and imprecision of three eGFR equations
| Group | eGFR equation | P | ||||
|---|---|---|---|---|---|---|
|
|
|
|||||
| 2009 CKD-EPI [A] | 2021 CKD-EPI [B] | EKFC [C] | [A] vs. [B] | [A] vs. [C] | [B] vs. [C] | |
| All (N = 1,654) | ||||||
| Median bias* (95% CI) | 1.8 (1.2–2.4) | 4.8 (4.1–5.4) | –0.3 (–1.2–0.4) | < 0.001 | < 0.001 | < 0.001 |
| P30† (95% CI), % | 78.2 (76.2–80.2) | 75.6 (73.5–77.6) | 80.0 (78.1–82.0) | < 0.001 | 0.003 | < 0.001 |
| RMSE (95% CI) | 17.0 (16.2–17.8) | 17.4 (16.5–18.1) | 16.7 (15.8–17.5) | |||
| mGFR ≥ 60 mL/min/1.73 m2 (N = 992) | ||||||
| Median bias* (95% CI) | –1.6 (–3.1 to –0.4) | 2.4 (1.1–4.0) | –5.2 (–6.8 to –4.0) | < 0.001 | < 0.001 | < 0.001 |
| P30† (95% CI), % | 88.6 (86.6–90.6) | 88.1 (86.1–90.1) | 89.9 (88.0–91.8) | 0.522 | 0.098 | 0.066 |
| RMSE (95% CI) | 19.3 (18.2–20.4) | 18.9 (17.9–20.0) | 19.4 (18.2–20.5) | |||
| mGFR < 60 mL/min/1.73 m2 (N = 662) | ||||||
| Median bias* (95% CI) | 4.3 (3.4–5.0) | 6.6 (5.4–7.5) | 3.2 (2.6–4.2) | < 0.001 | < 0.001 | < 0.001 |
| P30† (95% CI), % | 62.7 (59–66.4) | 56.8 (53–60.6) | 65.3 (61.6–68.9) | < 0.001 | 0.012 | < 0.001 |
| RMSE (95% CI) | 12.9 (11.6–14.0) | 14.7 (13.4–15.8) | 11.6 (10.5–12.6) | |||
| BMI < 20 (N = 151) | ||||||
| Median bias* (95% CI) | 11.1 (7.8–14.4) | 13.8 (9.8–17.0) | 8.0 (4.8–11.7) | < 0.001 | < 0.001 | < 0.001 |
| P30† (95% CI), % | 47.7 (39.7–55.6) | 45.7 (37.7–53.6) | 55.0 (47.0–62.9) | 0.453 | 0.003 | 0.001 |
| RMSE (95% CI) | 23.0 (19.5–25.9) | 24.6 (21.2–27.6) | 19.6 (16.5–22.3) | |||
| 20 ≤ BMI < 25 (N = 817) | ||||||
| Median bias* (95% CI) | 2.7 (1.9–3.6) | 6.0 (5.0–6.9) | 0.7 (–0.2–1.5) | < 0.001 | < 0.001 | < 0.001 |
| P30† (95% CI), % | 80.2 (77.4–82.9) | 75.4 (72.4–78.4) | 81.4 (78.7–84.1) | < 0.001 | 0.164 | < 0.001 |
| RMSE (95% CI) | 16.0 (14.8–17.1) | 16.7 (15.5–17.7) | 15.5 (14.3–16.7) | |||
| 25 ≤ BMI < 30 (N = 584) | ||||||
| Median bias* (95% CI) | –1.2 (–2.7 to –0.2) | 1.9 (0.7–3.1) | –3.1 (–4.2 to –1.6) | < 0.001 | < 0.001 | < 0.001 |
| P30† (95% CI), % | 82.2 (79.1–85.3) | 81.2 (78–84.3) | 83.6 (80.6–86.6) | 0.377 | 0.215 | 0.087 |
| RMSE (95% CI) | 16.5 (15.0–17.8) | 16.1 (14.8–17.3) | 16.9 (15.3–18.4) | |||
| BMI ≥ 30 (N = 102) | ||||||
| Median bias* (95% CI) | –5.2 (–8.2 to –1.5) | –2.2 (–5.1–2.0) | –6.2 (–9.3 to –3.6) | < 0.001 | < 0.001 | < 0.001 |
| P30† (95% CI), % | 85.3 (78.4–92.2) | 89.2 (83.2–95.2) | 86.3 (79.6–93.0) | 0.219 | 1.000 | 0.508 |
| RMSE (95% CI) | 17.6 (14.7–20.1) | 16.7 (14.0–19.0) | 19.5 (15.9–22.5) | |||
*Bias is calculated as eGFR minus mGFR in units of mL/min/1.73 m2. The Wilcoxon signed-rank test was used–compare the bias between eGFR equations.
†P30 is the proportion of eGFR within 30% of mGFR. The P30 of three eGFR equations was compared using McNemar test.
Abbreviations: BMI, body mass index (kg/m2); Chronic Kidney Disease Epidemiology Collaboration; CI, confidence interval; eGFR, estimated glomerular filtration rate; EKFC, European Kidney Function Consortium; mGFR, measured glomerular filtration rate; RMSE, root mean square error.