Table 4.

Performance of predictive dosing algorithms.

Algorithm	Mean absolute error (mg/week)
	EA and AA	EA	AA
Fixed 35 mg/week dose	13.7	13.5	15.2
US FDA table mid-value of range	12.7	12.4	15.0
IWPC (three variants)	10.0	9.5	13.8
New models
Clinical†	12.1 (11.3–12.6)	11.8 (11.1–12.4)	13.4 (11.3–14.9)
Limited genetic‡	9.8 (9.1–10.1)	9.3 (8.7–9.8)	12.9 (10.8–14.5)
Expanded genetic§	9.6 (8.9–9.8)	9.1 (8.4–9.6)	12.4 (10.0–13.2)
Dispensable regimen¶	9.6 (8.8–9.9)	9.1 (8.6–9.6)	12.4 (9.8–13.4)

For the novel models, the mean absolute error represents the validated bootstrap estimate and 95% CI in parentheses.

^†Includes age, gender, body surface area, race/ethnicity, smoking, amiodarone usage and indication (venous thromboembolism vs atrial fibrillation).

^‡Includes clinical and IWPC genetic variants (e.g., CYP2C9*2, CYP2C9*3 and VKORC1 rs9923231) as modeled in IWPC [37].

^§Includes clinical and VKORC1 rs9923231, CYP2C9 variants (*2, *3, *6, *8), CYP4F2 rs2108622, and CALU rs339097.

^¶Includes expanded genetic model variables rounded to nearest dispensable regimen using any single pill strength in 0.5, 1, 1.5 or 2 pill increments.

AA: African–American; EA: European–American; IWPC: International Warfarin Pharmacogenetics Consortium.