Table 4.

Minimum FVIII level to prevent total and spontaneous joint bleeds

Outcomes for all joint bleeds	AUC	YI	FVIII level
At least 1 joint bleeding episode in life∗	0.73	0.39	19.2
At least 1 joint bleeding episode in the 1st quartile of age (<28)†	0.68	0.34	19.2
At least 1 joint bleeding episode in the 2nd quartile of age (28 ≤ x < 45)‡	0.73	0.41	14.0
At least 1 joint bleeding episode in the 3rd quartile of age (45 ≤ x < 59)§	0.71	0.41	12.8
At least 1 joint bleeding episode in the 4th quartile of age (≥59)‖	0.80	0.47	14.3
Outcomes for spontaneous joint bleeds
At least 1 spontaneous joint bleeding episode in life¶	0.80	0.58	17.7
At least 1 spontaneous joint bleed in the 1st quartile of age (<28)#	0.85	0.67	17.7
At least 1 spontaneous joint bleed in the 2nd quartile of age (28 ≤ x < 45)∗∗	0.88	0.71	16.7
At least 1 spontaneous joint bleed in the 3rd quartile of age (45 ≤ x < 59)††	NA	NA	NA
At least 1 spontaneous joint bleed in the 4th quartile of age (≥59)‡‡	0.92	0.87	12.8

FVIII level indicates the minimum (trough) FVIII level to achieve zero joint bleeds (total or spontaneous).

NA, non applicable; YI, Youden Index (sensitivity + specificity – 1).

^∗Available in 270 patients.

^†Available in 266 patients.

^‡Available/applicable in 203 patients.

^§Available/applicable in 130 patients.

^‖Available/applicable in 66 patients

^¶Available in 240 patients.

^#Available in 238 patients.

^∗∗Available/applicable in 180 patients.

^††Available/applicable in 115 patients.

^‡‡Available/applicable in 56 patients.