Table 1. Characteristics of Red Blood Cell Transfusion Recipients in a Study of the Association of Donor Sex and Prior Pregnancy With Mortality Among Transfusion Recipients .
| Outcomes | Study Cohort, No. (%) | ||
|---|---|---|---|
| KPNC | REDS-III | SCANDAT | |
| No. of patients | 34 662 | 93 724 | 918 996 |
| Sex | |||
| Male | 16 010 (46.2) | 45 376 (48.4) | 396 757 (43.2) |
| Female | 18 652 (53.8) | 48 348 (51.6) | 522 239 (56.8) |
| Age at first transfusion, y | |||
| 0-17 | 0 | 3641 (3.9) | 25 695 (2.8) |
| 18-25 | 506 (1.5) | 2973 (3.2) | 16 528 (1.8) |
| 26-50 | 4046 (11.7) | 16 752 (17.9) | 111 696 (12.2) |
| 51-75 | 16 442 (47.4) | 47 773 (51.0) | 379 551 (41.3) |
| >75 | 13 468 (38.9) | 22 585 (24.1) | 385 526 (42.0) |
| Median (IQR), y | 71 (60-81) | 64 (51-75) | 72 (59-82) |
| Charlson comorbidity index at first transfusiona | |||
| 0 | 16 725 (48.3) | 31 023 (33.1) | 519 282 (56.5) |
| 1-2 | 10 786 (31.1) | 43 815 (46.7) | 299 674 (32.6) |
| 3-4 | 6243 (18.0) | 15 223 (16.2) | 73 828 (8.0) |
| 5-6 | 885 (2.6) | 3333 (3.6) | 20 778 (2.3) |
| 7-8 | 23 (0.1) | 319 (0.3) | 4620 (0.5) |
| 9-10 | 0 | 11 (<0.1) | 751 (0.1) |
| >10 | 0 | 0 | 63 |
| No. of transfusions administered during follow-up, U | |||
| 1-2 | 16 433 (47.4) | 48 193 (51.4) | 451 720 (49.2) |
| 3-4 | 8140 (23.5) | 19 886 (21.2) | 228 216 (24.8) |
| 5-9 | 6314 (18.2) | 15 896 (17.0) | 153 599 (16.7) |
| 10-49 | 3569 (10.3) | 9454 (10.1) | 81 139 (8.8) |
| ≥50 | 206 (0.6) | 295 (0.3) | 4322 (0.5) |
| Median (IQR), U | 3 (2-5) | 2 (1-5) | 3 (2-5) |
| No. of red blood cell transfusions from female donors, median (IQR), Ub | 1 (0-2) | 1 (0-2) | 1 (0-2) |
| No. of red blood cell transfusions from previously pregnant or parous female donors, median (IQR), Ub | 0 (0-0) | 0 (0-1) | 1 (0-1) |
| No. of sex-discordant red blood cell transfusions, median (IQR), Ub | 1 (1-2) | 1 (1-3) | 2 (1-3) |
Abbreviations: IQR, interquartile range; KPNC, Kaiser Permanente Northern California; REDS-III, Recipient Epidemiology and Donor Evaluation Study-III; SCANDAT, Scandinavian Donations and Transfusions.
a
The Charlson comorbidity index is composed of 22 conditions and scores on each are summed to create an overall score with a range from 0 to 41. A higher score implies a higher comorbidity burden.
b
Differences in the distributions of different types of transfused red blood cell units were largely driven by the ability of men to donate more frequently than women because of hemoglobin eligibility requirements and the physiology of iron recovery after donation.