Comparison of large and small centers
| . | Large centers . | Small centers . | P2* . |
|---|---|---|---|
| Number of centers | 10 | 19 | –— |
| Number of patients | 354 | 250 | — |
| Median (range) | 35 (25-49) | 13 (2-23) | — |
| Positive family history for inhibitors | 39 (11.0) | 18 (7.2) | .114 |
| High-risk FVIII gene mutation | 228 (64.4) | 138 (55.2) | .023 |
| Age (y) at diagnosis; median (IQR) | 0.5 (0.0-0.9) | 0.3 (0.0-0.8) | .703 |
| Age at first exposure; median (IQR) | 0.8 (0.5-1.1) | 0.8 (0.3-1.1) | .239 |
| Intensive treatment (≥5 EDs) at first exposure | 53 (15.0) | 40 (16.0) | .680 |
| Dose (IU/kg/ED) in first 5 EDs; median (IQR) | 82 (50-133) | 68 (50-92) | .001 |
| Product at first exposure | |||
| Plasma-derived | 62 (17.5) | 43 (17.2) | .895 |
| Recombinant | 290 (81.9) | 207 (82.8) | — |
| Recombinant product at first exposure | |||
| 1st generation full-length | 49 (13.8) | 19 (7.6) | .017 |
| 2nd generation full-length | 106 (29.9) | 81 (32.4) | .520 |
| 2nd generation B-domain–deleted | 37 (10.5) | 40 (16.0) | .044 |
| 3rd generation full-length | 96 (27.1) | 66 (26.4) | .844 |
| 3rd generation B-domain–deleted | 2 (0.6) | 1 (0.4) | .776 |
| ED at start prophylaxis; median (IQR) | 12 (5-22) | 13 (5-21) | .631 |
| Patients with clinically relevant inhibitors | 122 (34.5) | 60 (24.0) | .006 |
| Number of EDs at inhibitor development; median (IQR) | 14 (10-19) | 14 (8-19) | .938 |
| Patients with high-titer inhibitors | 82 (23.1) | 45 (18.0) | .125 |
| Patients with low-titer inhibitors | 40 (11.3) | 15 (6.0) | .026 |
| Frequency of testing3† | |||
| Tests per year; median (IQR) | 4.1 (2.3-8.2) | 2.6 (1.1-4.1) | .001 |
| Tests per 50 EDs; median (IQR) | 5 (3-7) | 3 (1-6) | .002 |
| . | Large centers . | Small centers . | P2* . |
|---|---|---|---|
| Number of centers | 10 | 19 | –— |
| Number of patients | 354 | 250 | — |
| Median (range) | 35 (25-49) | 13 (2-23) | — |
| Positive family history for inhibitors | 39 (11.0) | 18 (7.2) | .114 |
| High-risk FVIII gene mutation | 228 (64.4) | 138 (55.2) | .023 |
| Age (y) at diagnosis; median (IQR) | 0.5 (0.0-0.9) | 0.3 (0.0-0.8) | .703 |
| Age at first exposure; median (IQR) | 0.8 (0.5-1.1) | 0.8 (0.3-1.1) | .239 |
| Intensive treatment (≥5 EDs) at first exposure | 53 (15.0) | 40 (16.0) | .680 |
| Dose (IU/kg/ED) in first 5 EDs; median (IQR) | 82 (50-133) | 68 (50-92) | .001 |
| Product at first exposure | |||
| Plasma-derived | 62 (17.5) | 43 (17.2) | .895 |
| Recombinant | 290 (81.9) | 207 (82.8) | — |
| Recombinant product at first exposure | |||
| 1st generation full-length | 49 (13.8) | 19 (7.6) | .017 |
| 2nd generation full-length | 106 (29.9) | 81 (32.4) | .520 |
| 2nd generation B-domain–deleted | 37 (10.5) | 40 (16.0) | .044 |
| 3rd generation full-length | 96 (27.1) | 66 (26.4) | .844 |
| 3rd generation B-domain–deleted | 2 (0.6) | 1 (0.4) | .776 |
| ED at start prophylaxis; median (IQR) | 12 (5-22) | 13 (5-21) | .631 |
| Patients with clinically relevant inhibitors | 122 (34.5) | 60 (24.0) | .006 |
| Number of EDs at inhibitor development; median (IQR) | 14 (10-19) | 14 (8-19) | .938 |
| Patients with high-titer inhibitors | 82 (23.1) | 45 (18.0) | .125 |
| Patients with low-titer inhibitors | 40 (11.3) | 15 (6.0) | .026 |
| Frequency of testing3† | |||
| Tests per year; median (IQR) | 4.1 (2.3-8.2) | 2.6 (1.1-4.1) | .001 |
| Tests per 50 EDs; median (IQR) | 5 (3-7) | 3 (1-6) | .002 |
Data are N (%), unless otherwise stated.
ED, exposure days; IQR, interquartile range.
χ2 test for categorical variables and independent samples t tests for continuous variables.
For large centers, determined in 65 of 323 (20%) randomly selected non-inhibitor patients; for small centers, determined in all 73 non-inhibitor patients of 8 randomly selected centers.