Inhibitor characteristics
| Characteristics . | All inhibitors . | Range . | High-titer* inhibitors . | Range . | Low-titer* inhibitors . | Range . |
|---|---|---|---|---|---|---|
| No. patients (%) | 179 (100) | NA | 118 (66) | NA | 61 (34) | NA |
| No. exposure days at inhibitor development (IQR) | 14.5 (9.75-20)† | 3->75‡ | 15 (9.5-19)† | 3->75‡ | 14 (9.5-24.0) | 3-66 |
| Peak inhibitor titer (BU/mL) (IQR) | 18.0 (3.0-103.0) | 0.5-6351.0 | 50.5 (18.4-308.5) | 5.4-6351.0 | 2 (1.1-3.0) | 0.5-4.4 |
| Age at inhibitor development, mo. (IQR) | 15.5 (10.8-19.6) | 8d-6.8y | 14.0 (9.4-18.0) | 8d-6.8y | 17.1 (13.5-23.9) | 20d-3.2y |
| Duration between first exposure day and inhibitor development, mo. (IQR) | 4.3 (1.6-8.2)† | 7d-5.9y | 3.5 (1.4-7.4)† | 7d-5.9y | 5.7 (3.1-10.3) | 8d-2.4y |
| Characteristics . | All inhibitors . | Range . | High-titer* inhibitors . | Range . | Low-titer* inhibitors . | Range . |
|---|---|---|---|---|---|---|
| No. patients (%) | 179 (100) | NA | 118 (66) | NA | 61 (34) | NA |
| No. exposure days at inhibitor development (IQR) | 14.5 (9.75-20)† | 3->75‡ | 15 (9.5-19)† | 3->75‡ | 14 (9.5-24.0) | 3-66 |
| Peak inhibitor titer (BU/mL) (IQR) | 18.0 (3.0-103.0) | 0.5-6351.0 | 50.5 (18.4-308.5) | 5.4-6351.0 | 2 (1.1-3.0) | 0.5-4.4 |
| Age at inhibitor development, mo. (IQR) | 15.5 (10.8-19.6) | 8d-6.8y | 14.0 (9.4-18.0) | 8d-6.8y | 17.1 (13.5-23.9) | 20d-3.2y |
| Duration between first exposure day and inhibitor development, mo. (IQR) | 4.3 (1.6-8.2)† | 7d-5.9y | 3.5 (1.4-7.4)† | 7d-5.9y | 5.7 (3.1-10.3) | 8d-2.4y |
Values are medians (IQR) or numbers (%). NA, not applicable.
High-titer inhibitor was defined as a clinically relevant inhibitor with a peak titer of at least 5 BU/mL, and alow-titer inhibitor was defined as a clinically relevant inhibitor with a peak titer of less than 5 BU/mL.
Unknown in 1 high-titer inhibitor patient.
The patient with inhibitor development after 75 exposure days was a newborn who underwent a surgical procedure after birth with subsequent daily “prophylaxis” 500 IU until inhibitor detection at age 3 months.