Table 2.

Mean FVIII levels in patients with and without a history of joint bleeds

	At least 1 joint bleed (n=100)	No joint bleeds (n=170)∗	Mean difference (95% CI)	P value
FVIII:C† mean (SD)	17.8 (10.8)	26.8 (11.6)	–9.0 (–11.7 to –6.2)	<.0001

	At least 1 spontaneous joint bleed (n=10)	No spontaneous joint bleeds (n=230)‡	Mean difference (95% CI)	P value
FVIII:C† mean (SD)	13.8 (9.9)	25.0 (11.9)	–11.1 (–18.3 to –3.9)	.0063

Mean differences with CI and P values have been assessed using the t test.

FVIII:C, factor VIII coagulant activity.

^∗Available in 270 patients.

^†For each patient, the mean level of all FVIII:C performed in life by 1 stage clotting assay.

^‡Available in 240 patients.