Clinical correlates of low BMD in the SCCRIP BMD cohort
| Variable . | All (N = 306) . | Female (n = 153) . | Male (n = 153) . | |||
|---|---|---|---|---|---|---|
| Normal BMD (n = 250 [81.7%]) . | Low BMD (n = 56 [18.3%]) . | Normal BMD (n = 128 [83.7%]) . | Low BMD (n = 25 [16.3%]) . | Normal BMD (n = 122 [79.7%]) . | Low BMD (n = 31 [20.3%]) . | |
| SCD genotype | ||||||
| HbSS/Sβ0-thalassemia | 152 (60.8)* | 45 (80.4)* | 75 (58.6)* | 19 (76.0)* | 77 (63.1)* | 26 (83.9)* |
| HbSC | 76 (30.4)* | 4 (7.1)* | 44 (34.4)* | 2 (8.0)* | 32 (26.3)* | 2(6.4)* |
| HbSβ+-thalassemia | 22 (8.8)* | 7 (12.5)* | 9 (7.1)* | 4 (16.0)* | 13 (10.7)* | 3 (9.7)* |
| Age at DXA, y | 11.9 ± 4.09* | 14.5 ± 2.75* | 12.2 ± 4.18 | 14.2 ± 2.77 | 11.7 ± 3.98* | 14.7 ± 2.77* |
| Age category | ||||||
| School-age | 92 (36.8)* | 4 (7.1)* | 44 (33.9)* | 2 (8.0)* | 48 (39.3)* | 2 (6.5)* |
| Adolescent | 158 (63.2)* | 52 (92.9)* | 84 (65.6)* | 23 (92.0)* | 74 (60.7)* | 29 (93.6)* |
| VOEs per year (total) | 0.25 ± 0.44 | 0.22 ± 0.48 | 0.21 ± 0.37 | 0.27 ± 0.59 | 0.29 ± 0.50 | 0.19 ± 0.39 |
| VOEs per year (2 y to DXA) | 0.58 ± 2.12 | 0.71 ± 1.70 | 0.47 ± 1.48 | 0.56 ± 1.23 | 0.69 ± 2.54 | 0.84 ± 2.57 |
| VOEs total (categorical) | ||||||
| <5 times | 141 (56.4) | 35 (62.5 | 67 (52.3) | 17 (68.0) | 74 (60.7) | 18 (58.1) |
| 5-10 times | 63 (25.2) | 11 (19.6) | 43 (33.6) | 3 (12.0) | 20 (16.4) | 8 (25.8) |
| >10 times | 46 (18.4) | 10 (17.9) | 18 (14.1) | 5 (20.0) | 28 (22.9) | 5 (16.1) |
| Hydroxyurea use | ||||||
| No | 109 (43.6) | 16 (28.6) | 57 (44.5) | 8 (32.0) | 52 (42.6) | 8 (25.8) |
| Yes | 141 (56.4) | 40 (71.4) | 71 (55.5) | 17 (68.0) | 70 (57.4) | 23 (74.2) |
| Hydroxyurea duration | ||||||
| <5 y | 187 (74.8) | 34 (60.7) | 97 (75.8) | 16 (64.0) | 90 (73.6) | 18 (58.1) |
| 5-10 y | 41 (16.4) | 15 (27.8) | 22 (17.2) | 7 (28.0) | 19 (15.6) | 8 (25.8) |
| >10 y | 22 (8.8) | 7 (12.5) | 9 (7.0) | 2 (8.0) | 13 (10.7) | 5 (16.1) |
| Hydroxyurea duration, y | 2.9 ± 3.95* | 4.1 ± 4.31* | 2.8 ± 3.88 | 3.6 ± 3.88 | 3.1 ± 4.03 | 4.4 ± 4.66 |
| Chronic RBC transfusions† | ||||||
| No | 245 (98.0) | 52 (92.9) | 125 (97.7) | 22 (88.0) | 120 (98.4) | 30 (96.8) |
| Yes | 5 (2.0) | 4 (7.1) | 3 (2.3) | 3 (12.0) | 2 (1.6) | 1 (3.2) |
| Chronic pain | ||||||
| No | 244 (97.6) | 51 (91.1) | 125 (97.7) | 24 (96.0) | 119 (97.5) | 27 (87.1) |
| Yes | 6 (2.4)* | 5 (8.9)* | 3 (2.3) | 1 (4.0) | 3 (2.5)* | 4 (12.9)* |
| Hip osteonecrosis | ||||||
| No | 242 (96.8) | 49 (87.5) | 126 (98.4) | 24 (96.0) | 116 (95.1) | 25 (80.7) |
| Yes | 8 (3.2)* | 7 (12.5)* | 2 (1.6) | 1 (4.0) | 6 (4.9)* | 6 (19.3)* |
| Hip osteonecrosis grade‡ | ||||||
| Less severe | 3 (1.2)* | 2 (3.6)* | 1 (0.8) | 0 (0) | 2 (1.6)* | 2 (6.5)* |
| Severe | 5 (2.0)* | 5 (8.9)* | 1 (0.8) | 1 (4.0) | 4 (3.3)* | 4 (12.9)* |
| None | 242 (96.8) | 49 (87.5) | 126 (98.4) | 24 (96.0) | 116 (95.1) | 25 (80.6) |
| Vitamin D status§ | ||||||
| Normal | 68 (28.8) | 9 (17.7) | 31 (25.4) | 2 (8.0) | 37 (32.5) | 7 (26.9) |
| Insufficient | 91 (38.6) | 23 (45.1) | 54 (44.3) | 10 (40.0) | 37 (32.5) | 13 (50.0) |
| Deficient | 77 (32.6) | 19 (37.3) | 37 (30.3) | 13 (52.0) | 40 (35.1) | 6 (23.1) |
| Variable . | All (N = 306) . | Female (n = 153) . | Male (n = 153) . | |||
|---|---|---|---|---|---|---|
| Normal BMD (n = 250 [81.7%]) . | Low BMD (n = 56 [18.3%]) . | Normal BMD (n = 128 [83.7%]) . | Low BMD (n = 25 [16.3%]) . | Normal BMD (n = 122 [79.7%]) . | Low BMD (n = 31 [20.3%]) . | |
| SCD genotype | ||||||
| HbSS/Sβ0-thalassemia | 152 (60.8)* | 45 (80.4)* | 75 (58.6)* | 19 (76.0)* | 77 (63.1)* | 26 (83.9)* |
| HbSC | 76 (30.4)* | 4 (7.1)* | 44 (34.4)* | 2 (8.0)* | 32 (26.3)* | 2(6.4)* |
| HbSβ+-thalassemia | 22 (8.8)* | 7 (12.5)* | 9 (7.1)* | 4 (16.0)* | 13 (10.7)* | 3 (9.7)* |
| Age at DXA, y | 11.9 ± 4.09* | 14.5 ± 2.75* | 12.2 ± 4.18 | 14.2 ± 2.77 | 11.7 ± 3.98* | 14.7 ± 2.77* |
| Age category | ||||||
| School-age | 92 (36.8)* | 4 (7.1)* | 44 (33.9)* | 2 (8.0)* | 48 (39.3)* | 2 (6.5)* |
| Adolescent | 158 (63.2)* | 52 (92.9)* | 84 (65.6)* | 23 (92.0)* | 74 (60.7)* | 29 (93.6)* |
| VOEs per year (total) | 0.25 ± 0.44 | 0.22 ± 0.48 | 0.21 ± 0.37 | 0.27 ± 0.59 | 0.29 ± 0.50 | 0.19 ± 0.39 |
| VOEs per year (2 y to DXA) | 0.58 ± 2.12 | 0.71 ± 1.70 | 0.47 ± 1.48 | 0.56 ± 1.23 | 0.69 ± 2.54 | 0.84 ± 2.57 |
| VOEs total (categorical) | ||||||
| <5 times | 141 (56.4) | 35 (62.5 | 67 (52.3) | 17 (68.0) | 74 (60.7) | 18 (58.1) |
| 5-10 times | 63 (25.2) | 11 (19.6) | 43 (33.6) | 3 (12.0) | 20 (16.4) | 8 (25.8) |
| >10 times | 46 (18.4) | 10 (17.9) | 18 (14.1) | 5 (20.0) | 28 (22.9) | 5 (16.1) |
| Hydroxyurea use | ||||||
| No | 109 (43.6) | 16 (28.6) | 57 (44.5) | 8 (32.0) | 52 (42.6) | 8 (25.8) |
| Yes | 141 (56.4) | 40 (71.4) | 71 (55.5) | 17 (68.0) | 70 (57.4) | 23 (74.2) |
| Hydroxyurea duration | ||||||
| <5 y | 187 (74.8) | 34 (60.7) | 97 (75.8) | 16 (64.0) | 90 (73.6) | 18 (58.1) |
| 5-10 y | 41 (16.4) | 15 (27.8) | 22 (17.2) | 7 (28.0) | 19 (15.6) | 8 (25.8) |
| >10 y | 22 (8.8) | 7 (12.5) | 9 (7.0) | 2 (8.0) | 13 (10.7) | 5 (16.1) |
| Hydroxyurea duration, y | 2.9 ± 3.95* | 4.1 ± 4.31* | 2.8 ± 3.88 | 3.6 ± 3.88 | 3.1 ± 4.03 | 4.4 ± 4.66 |
| Chronic RBC transfusions† | ||||||
| No | 245 (98.0) | 52 (92.9) | 125 (97.7) | 22 (88.0) | 120 (98.4) | 30 (96.8) |
| Yes | 5 (2.0) | 4 (7.1) | 3 (2.3) | 3 (12.0) | 2 (1.6) | 1 (3.2) |
| Chronic pain | ||||||
| No | 244 (97.6) | 51 (91.1) | 125 (97.7) | 24 (96.0) | 119 (97.5) | 27 (87.1) |
| Yes | 6 (2.4)* | 5 (8.9)* | 3 (2.3) | 1 (4.0) | 3 (2.5)* | 4 (12.9)* |
| Hip osteonecrosis | ||||||
| No | 242 (96.8) | 49 (87.5) | 126 (98.4) | 24 (96.0) | 116 (95.1) | 25 (80.7) |
| Yes | 8 (3.2)* | 7 (12.5)* | 2 (1.6) | 1 (4.0) | 6 (4.9)* | 6 (19.3)* |
| Hip osteonecrosis grade‡ | ||||||
| Less severe | 3 (1.2)* | 2 (3.6)* | 1 (0.8) | 0 (0) | 2 (1.6)* | 2 (6.5)* |
| Severe | 5 (2.0)* | 5 (8.9)* | 1 (0.8) | 1 (4.0) | 4 (3.3)* | 4 (12.9)* |
| None | 242 (96.8) | 49 (87.5) | 126 (98.4) | 24 (96.0) | 116 (95.1) | 25 (80.6) |
| Vitamin D status§ | ||||||
| Normal | 68 (28.8) | 9 (17.7) | 31 (25.4) | 2 (8.0) | 37 (32.5) | 7 (26.9) |
| Insufficient | 91 (38.6) | 23 (45.1) | 54 (44.3) | 10 (40.0) | 37 (32.5) | 13 (50.0) |
| Deficient | 77 (32.6) | 19 (37.3) | 37 (30.3) | 13 (52.0) | 40 (35.1) | 6 (23.1) |
Data are presented as n (%) or mean ± standard deviation.
P < .05 between low vs normal BMD per variable.
Defined as RBC transfusions ≥4 times/year.
Less severe, necrotic lesion ≤30% femoral head volume; severe, necrotic lesion >30% femoral head volume.
Normal, 25(OH)D, >30 ng/mL; insufficient, 25(OH)D 20 to 30 ng/mL; and deficient, 25(OH)D <20 ng/mL.