The equation used by egfr() with method = "CKDEPI 2009".
Details
The CKD-EPI 2009 equation: $$eGFR = 141 \cdot \min(S_{cr}/\kappa, 1)^\alpha \cdot \max(S_{cr}/\kappa, 1)^{-1.209} \cdot 0.993^A \cdot 1.018^F \cdot 1.159^B$$
where:
\(S_{cr}\) = serum creatinine (mg/dL)
\(\kappa\) = 0.7 (female) or 0.9 (male)
\(\alpha\) = -0.329 (female) or -0.411 (male)
\(A\) = age (years)
\(F\) = 1 (female) or 0 (male)
\(B\) = 1 (Black) or 0 (other)