Table 1 Inhibitor incidence by age,... | American Society of Hematology

Table 1

Inhibitor incidence by age, 1990-2009

	Years at risk	n	Incidence*	Incident rate ratio	P	95% CI
Low-titer inhibitors (< 5 BU/mL)†
Age, y
0-4	2411	61	25.30	18.03	.00	11.53-28.20
5-9	2779	17	6.12	4.36	.00	2.39-7.96
10-49	19 953	28	1.40	1.00	—	—
50-59	2094	1	0.48	0.34	.29	0.05-2.50
≥60	1621	4	2.47	1.76	.29	0.62-5.01
Total	28 858	111	3.85
High-titer inhibitors (≥ 5 BU/mL)†
Age, y
0-4	2411	87	36.08	13.33	.00	9.49-18.72
5-9	2779	8	2.88	1.06	.87	0.51-2.24
10-49	19 953	54	2.71	1.00	—	—
50-59	2094	9	4.30	1.59	.20	0.78-3.22
≥60	1621	11	6.79	2.51	.01	1.31-4.80
Total	28 858	169	5.86
All inhibitors
Age, y
0-4	2411	155	64.29	12.10	.00	9.45-15.49
5-9	2779	26	9.36	1.76	.01	1.15-2.70
10-49	19 953	106	5.31	1.00	—	—
50-59	2094	11	5.25	0.99	.97	0.53-1.84
≥60	1621	17	10.49	1.97	.01	1.18-3.29
Total	28 858	315	10.92

	Years at risk	n	Incidence*	Incident rate ratio	P	95% CI
Low-titer inhibitors (< 5 BU/mL)†
Age, y
0-4	2411	61	25.30	18.03	.00	11.53-28.20
5-9	2779	17	6.12	4.36	.00	2.39-7.96
10-49	19 953	28	1.40	1.00	—	—
50-59	2094	1	0.48	0.34	.29	0.05-2.50
≥60	1621	4	2.47	1.76	.29	0.62-5.01
Total	28 858	111	3.85
High-titer inhibitors (≥ 5 BU/mL)†
Age, y
0-4	2411	87	36.08	13.33	.00	9.49-18.72
5-9	2779	8	2.88	1.06	.87	0.51-2.24
10-49	19 953	54	2.71	1.00	—	—
50-59	2094	9	4.30	1.59	.20	0.78-3.22
≥60	1621	11	6.79	2.51	.01	1.31-4.80
Total	28 858	169	5.86
All inhibitors
Age, y
0-4	2411	155	64.29	12.10	.00	9.45-15.49
5-9	2779	26	9.36	1.76	.01	1.15-2.70
10-49	19 953	106	5.31	1.00	—	—
50-59	2094	11	5.25	0.99	.97	0.53-1.84
≥60	1621	17	10.49	1.97	.01	1.18-3.29
Total	28 858	315	10.92

Per 1000 patient-years at risk.

Where titer measurements were known.