Characteristics of study population
| Characteristic . | Controls (n = 37), n (%) . | Cases (n = 20), n (%) . | χ2 . | P . |
|---|---|---|---|---|
| Intensive FVIII treatment | 6 (16) | 10 (50) | 7.34 | .01 |
| Age, y | ||||
| <30 | 21 (57) | 7 (35) | 2.55 | .27 |
| 30-60 | 13 (35) | 10 (50) | ||
| >60 | 3 (8) | 3 (15) | ||
| Race | ||||
| White | 31 (84) | 19 (95) | 1.62 | .44 |
| African American | 5 (13) | 1 (5) | ||
| Other | 1 (3) | 0 (0) | ||
| Hispanic ethnicity | 3 (8) | 1 (5) | 0.19 | .66 |
| Family history of inhibitor | 5 (14) | 3 (15) | 0.02 | .88 |
| HCV antibody positive | 15 (41) | 7 (35) | 1.42 | .49 |
| HIV antibody positive | 1 (3) | 0 (0) | 0.74 | .69 |
| Baseline FVIII | ||||
| 1% ≤ FVIII:C < 2% | 2 (5) | 4 (20) | 3.52 | .17 |
| 2% ≤ FVIII:C ≤ 5% | 15 (41) | 5 (25) | ||
| FVIII:C > 5% | 20 (54) | 11 (55) | ||
| Age at first factor infusion, y | ||||
| Unknown | 1 (3) | 0 (0) | ||
| ≤2 | 11 (30) | 3 (15) | 4.25 | .12 |
| 3-10 | 15 (41) | 6 (30) | ||
| >10 | 10 (27) | 11 (55) | ||
| Prior FVIII exposure, d | ||||
| ≤20 | 9 (24) | 2 (10) | 4.87 | .18 |
| 21-50 | 7 (19) | 9 (45) | ||
| 51-100 | 7 (19) | 3 (15) | ||
| >100 | 14 (38) | 6 (30) | ||
| Product during prior year | ||||
| Unknown | 0 (0) | 1 (5) | ||
| Plasma derived | 8 (22) | 3 (15) | 1.37 | .50 |
| Recombinant | 24 (65) | 15 (75) | ||
| None | 5 (13) | 1 (5) | ||
| Specific missense mutations | ||||
| p.Arg612Cys | 2 (5) | 6 (30) | 6.51 | .01 |
| p.Asn1942Ser | 4 (11) | 5 (25) | 1.97 | .16 |
| p.Arg2169His | 1 (3) | 3 (15) | 3.01 | .08 |
| p.Trp2248Cys | 1 (3) | 0 (0) | 0.55 | .46 |
| Characteristic . | Controls (n = 37), n (%) . | Cases (n = 20), n (%) . | χ2 . | P . |
|---|---|---|---|---|
| Intensive FVIII treatment | 6 (16) | 10 (50) | 7.34 | .01 |
| Age, y | ||||
| <30 | 21 (57) | 7 (35) | 2.55 | .27 |
| 30-60 | 13 (35) | 10 (50) | ||
| >60 | 3 (8) | 3 (15) | ||
| Race | ||||
| White | 31 (84) | 19 (95) | 1.62 | .44 |
| African American | 5 (13) | 1 (5) | ||
| Other | 1 (3) | 0 (0) | ||
| Hispanic ethnicity | 3 (8) | 1 (5) | 0.19 | .66 |
| Family history of inhibitor | 5 (14) | 3 (15) | 0.02 | .88 |
| HCV antibody positive | 15 (41) | 7 (35) | 1.42 | .49 |
| HIV antibody positive | 1 (3) | 0 (0) | 0.74 | .69 |
| Baseline FVIII | ||||
| 1% ≤ FVIII:C < 2% | 2 (5) | 4 (20) | 3.52 | .17 |
| 2% ≤ FVIII:C ≤ 5% | 15 (41) | 5 (25) | ||
| FVIII:C > 5% | 20 (54) | 11 (55) | ||
| Age at first factor infusion, y | ||||
| Unknown | 1 (3) | 0 (0) | ||
| ≤2 | 11 (30) | 3 (15) | 4.25 | .12 |
| 3-10 | 15 (41) | 6 (30) | ||
| >10 | 10 (27) | 11 (55) | ||
| Prior FVIII exposure, d | ||||
| ≤20 | 9 (24) | 2 (10) | 4.87 | .18 |
| 21-50 | 7 (19) | 9 (45) | ||
| 51-100 | 7 (19) | 3 (15) | ||
| >100 | 14 (38) | 6 (30) | ||
| Product during prior year | ||||
| Unknown | 0 (0) | 1 (5) | ||
| Plasma derived | 8 (22) | 3 (15) | 1.37 | .50 |
| Recombinant | 24 (65) | 15 (75) | ||
| None | 5 (13) | 1 (5) | ||
| Specific missense mutations | ||||
| p.Arg612Cys | 2 (5) | 6 (30) | 6.51 | .01 |
| p.Asn1942Ser | 4 (11) | 5 (25) | 1.97 | .16 |
| p.Arg2169His | 1 (3) | 3 (15) | 3.01 | .08 |
| p.Trp2248Cys | 1 (3) | 0 (0) | 0.55 | .46 |