Size of bruises in children with and without inherited bleeding disorders
| Size of bruise Mean (SD)* | Modelled ratio of bruise size (95% CI) | Number and percentage of bruises >1 cm | Number and percentage of collections with at least 1 bruise >1 cm | Modelled OR for collection with a bruise >1 cm | Number and percentage of collections with at least 5 bruises >1 cm | Total bruise size per collection Mean (SD) | Modelled ratio of total bruise size (95% CI) | |
|---|---|---|---|---|---|---|---|---|
| Premobile | ||||||||
| Non-BD | 0.84 (0.52) | 1 | 11/74 (14.9%) | 10/1002 (1.0%) | 1 | 0/1002 (0%) | 0.06 (0.32) | 1 |
| Mild/moderate BD | 1.37 (0.97) | 1.51 (0.82 to 2.10) | 4/11 (36.4%) | 2/59 (3.4%) | 5.94 (0.61 to 20.38) | 0/59 (0%) | 0.26 (1.10) | 1.39 (1.16 to 1.53)† |
| Severe BD | 1.31 (1.10) | 1.81 (1.22 to 2.23)† | 17/51 (33.3%) | 14/57 (24.6%) | 112.6 (11.99 to 378.3)† | 0/57 (0%) | 1.15 (2.01) | 2.32 (1.92 to 2.57)† |
| Early mobile | ||||||||
| Non-BD | 0.95 (0.86) | 1 | 84/335 (25.1%) | 67/451 (14.9%) | 1 | 0/451 (0%) | 0.71 (1.30) | 1 |
| Mild/moderate BD | 1.06 (1.22) | 1.22 (0.83 to 1.50) | 43/173 (24.9%) | 23/68 (33.8%) | 3.38 (1.63 to 5.02)† | 2/68 (2.9%) | 2.71 (4.36) | 1.83 (1.30 to 2.21)† |
| Severe BD off prophylaxis | 1.54 (1.21) | 1.60 (1.05 to 2.01)† | 99/226 (43.8%) | 31/41 (75.6%) | 40.81 (7.01 to 105.8)† | 9/41 (22.0%) | 8.51 (8.27) | 4.66 (2.96 to 5.95)† |
| Walking | ||||||||
| Non-BD | 0.95 (0.80) | 1 | 671/2871 (23.4%) | 413/1027 (40.2%) | 1 | 8/1072 (0.8%) | 2.65 (2.96) | 1 |
| Mild/moderate BD | ||||||||
| All patients | 1.20 (0.91) | 1.16 (1.01 to 1.24)† | 512/1681 (30.5%) | 205/350 (58.6%) | 2.87 (1.47 to 4.13)† | 24/350 (6.9%) | 5.77 (6.64) | 1.62 (1.28 to 1.84)† |
| Haemophilia | 212/797 (26.6%) | 111/199 (55.8%) | 4.49 (4.41) | |||||
| VWD | 300/884 (33.9%) | 94/151 (62.3%) | 7.46 (8.48) | |||||
| Severe BD off prophylaxis | ||||||||
| All patients | 1.43 (1.24) | 1.47 (1.27 to 1.59)* | 350/992 (35.3%) | 116/190 (61.1%) | 3.43 (1.52 to 5.32)† | 28/190 (14.7%) | 7.44 (8.45) | 2.17 (1.67 to 2.50)† |
| Haemophilia | 1.51 (1.35) | 267/706 (37.8%) | 95/160 (59.4%) | 6.65 (7.70) | ||||
| VWD | 1.23 (0.90) | 83/286 (29.0%) | 21/30 (70.0%) | 11.69 (10.87) | ||||
| Severe BD on prophylaxis | ||||||||
| All patients | 1.49 (1.24) | 1.41 (1.23 to 1.52)† | 396/1019 (38.9%) | 135/191 (61.1%) | 5.78 (2.55 to 9.01)† | 27/191 (14.1%) | 7.97 (7.98) | 2.12 (1.63 to 2.44)† |
| Haemophilia | 1.50 (1.25) | 393/1001 (39.3%) | 132/183 (72.1%) | 8.21 (8.07) | ||||
| VWD | 1.08 (0.46) | 3/18 (16.7%) | 3/8 (37.5%) | 2.44 (0.98 | ||||
*The mean size of bruises reported may not reflect the actual bruise size because of variation in measurements and individual subjects contribute multiple collections. The relative size of bruises as described by modelled ratios show more reliable differences between groups because all subjects used the same collection methodology and multiple collections have been taken into account through multilevel modelling. The logistic regression investigated the presence of at least one large bruise or not. The categories were: At least 1 bruise >1 cm versus no bruise >1 cm and the latter included collections with no bruises.
†Indicated a statistically significant difference compared with children without a bleeding disorder. Of the 9136 bruises from both groups of children, size was not recorded for 1100 (12%). The proportion of missing bruise sizes varied little across development stages and bleeding disorder status except for two children in the early mobile group, of whom one had 46 and the other 229 bruises with no recorded sizes across collections and were responsible for the high proportion of missing values in this developmental group. Collections with incomplete data on sizes were excluded, resulting in the removal of 279 collections from 98 subjects on whom 1695 bruises were reported, leaving 3437 collections and 7441 bruises for analysis of size.
BD, bleeding disorder; VWD, von Willebrand disease.