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Table. 2.

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.

Ann Lab Med 2023;43:244~252 https://doi.org/10.3343/alm.2023.43.3.244

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