Table 1.
Sample characteristics of cases (AVN) and controls (no AVN)
| Variable | Total, N = 174 | AVN, n = 87 | No AVN, n = 87 |
|---|---|---|---|
| Female sex (%) | 104 (59.8) | 52 (59.8) | 52 (59.8) |
| Mean (range) years olda | |||
| Start age | 32 ± 12 (7–68) | 32 ± 12 (7–61) | 33 ± 12 (18–68) |
| End age | 41 ± 11 (24–71) | 41 ± 12 (24–68) | 41 ± 11 (24–71) |
| SS genotype (%) | 126 (72.4) | 66 (75.9) | 60 (69.0) |
| Total follow-up years | 1381 | 698 | 683 |
| Median (IQR) follow-up years per patient | 7 (5–10) | 7 (5–10) | 7 (5–10) |
AVN, avascular necrosis; IQR, interquartile range; SS, Sβ0 thalassemia.
a
Start age corresponds with baseline date, defined as date of AVN diagnosis and/or date of established care (controls). End age corresponds with age of death or as of January 31, 2014; cases and controls were matched by end age.