Patient characteristics
| . | All (N = 204) . | Group 1 (n = 58) . | Group 2 (n = 34) . | Group 3 (n = 72) . | Group 4 (n = 40) . | Raw P . | PFDR . |
|---|---|---|---|---|---|---|---|
| Age, y | 10.60 (3.65) | 8.75 (2.85) | 9.92 (3.33) | 12.05 (3.51) | 11.25 (3.99) | <.0001 | <.0001 |
| Sex, n (%) | .78 | .89 | |||||
| Male | 96 (47.06) | 28 (48.28) | 16 (47.06) | 36 (50) | 16 (40) | ||
| Female | 108 (52.94) | 30 (51.72) | 18 (52.94) | 36 (50) | 24 (60) | ||
| Genotype, n (%) | .23 | .32 | |||||
| HbSS | 191 (93.63) | 54 (93.10) | 31 (91.18) | 66 (91.67) | 40 (100) | ||
| HbS/β0 | 13 (6.37) | 4 (6.90) | 3 (8.82) | 6 (8.33) | 0 (0) | ||
| Splenectomy, n (%) | .27 | .33 | |||||
| Yes | 35 (17.16) | 8 (13.79) | 3 (8.82) | 14 (19.44) | 10 (25) | ||
| No | 169 (82.84) | 50 (86.21) | 31 (91.18) | 58 (80.56) | 30 (75) | ||
| Duration of therapy, y | 6.09 (4.21) | N/A | 1.20 (0.69) | 7.77 (3.84) | 7.23 (3.39) | <.001 | <.0001 |
| Dose of HU, mg/kg per day | 23.96 (4.06) | N/A | 22.72 (4.28) | 24.62 (3.8) | N/A | .03 | .04 |
| MCV at baseline, fL | 92.81 (14.34) | 84.21 (9.38) | 85.69 (10.35) | 106.16 (13.45) | 87.63 (3.83) | <.0001 | <.0001 |
| MCV at year 2, fL | 94.39 (14.75) | 82.91 (9.58) | 99.94 (11.54) | 104.86 (14.55) | 87.19 (3.53) | <.0001 | <.0001 |
| HbF at baseline, % | 12.99 (9.26) | 13.97 (8.17) | 9.72 (5.89) | 19.45 (8.08) | 3.04 (3.07) | <.0001 | <.0001 |
| HbF at year 2, % | 13.48 (9.25) | 11.79 (6.09) | 19.83 (9.38) | 17.75 (7.33) | 2.80 (2.36) | <.0001 | <.0001 |
| Hb at baseline, g/dL | 9.01 (1.21) | 8.59 (0.92) | 8.35 (1.17) | 9.31 (1.25) | 9.64 (1.06) | <.0001 | <.0001 |
| Hb at year 2, g/dL | 9.28 (1.14) | 8.78 (0.90) | 9.37 (1.22) | 9.44 (1.20) | 9.68 (1.07) | <.01 | <.01 |
| TRV at baseline, m/s | 2.40 (0.29) | 2.37 (0.34) | 2.41 (0.27) | 2.41 (0.26) | 2.41 (0.29) | .98 | .98 |
| TRV at baseline ≥2.5 m/s, n (%) | 69 (33.82) | 18 (31.03) | 12 (35.29) | 24 (33.33) | 15 (37.50) | .92 | .98 |
| TRV at year 2, m/s | 2.34 (0.28) | 2.39 (0.24) | 2.28 (0.25) | 2.30 (0.31) | 2.39 (0.27) | .02 | .04 |
| TRV at year 2 ≥2.5 m/s, n (%) | 56 (27.45) | 18 (31.03) | 7 (20.59) | 16 (22.22) | 15 (37.50) | .24 | .32 |
| . | All (N = 204) . | Group 1 (n = 58) . | Group 2 (n = 34) . | Group 3 (n = 72) . | Group 4 (n = 40) . | Raw P . | PFDR . |
|---|---|---|---|---|---|---|---|
| Age, y | 10.60 (3.65) | 8.75 (2.85) | 9.92 (3.33) | 12.05 (3.51) | 11.25 (3.99) | <.0001 | <.0001 |
| Sex, n (%) | .78 | .89 | |||||
| Male | 96 (47.06) | 28 (48.28) | 16 (47.06) | 36 (50) | 16 (40) | ||
| Female | 108 (52.94) | 30 (51.72) | 18 (52.94) | 36 (50) | 24 (60) | ||
| Genotype, n (%) | .23 | .32 | |||||
| HbSS | 191 (93.63) | 54 (93.10) | 31 (91.18) | 66 (91.67) | 40 (100) | ||
| HbS/β0 | 13 (6.37) | 4 (6.90) | 3 (8.82) | 6 (8.33) | 0 (0) | ||
| Splenectomy, n (%) | .27 | .33 | |||||
| Yes | 35 (17.16) | 8 (13.79) | 3 (8.82) | 14 (19.44) | 10 (25) | ||
| No | 169 (82.84) | 50 (86.21) | 31 (91.18) | 58 (80.56) | 30 (75) | ||
| Duration of therapy, y | 6.09 (4.21) | N/A | 1.20 (0.69) | 7.77 (3.84) | 7.23 (3.39) | <.001 | <.0001 |
| Dose of HU, mg/kg per day | 23.96 (4.06) | N/A | 22.72 (4.28) | 24.62 (3.8) | N/A | .03 | .04 |
| MCV at baseline, fL | 92.81 (14.34) | 84.21 (9.38) | 85.69 (10.35) | 106.16 (13.45) | 87.63 (3.83) | <.0001 | <.0001 |
| MCV at year 2, fL | 94.39 (14.75) | 82.91 (9.58) | 99.94 (11.54) | 104.86 (14.55) | 87.19 (3.53) | <.0001 | <.0001 |
| HbF at baseline, % | 12.99 (9.26) | 13.97 (8.17) | 9.72 (5.89) | 19.45 (8.08) | 3.04 (3.07) | <.0001 | <.0001 |
| HbF at year 2, % | 13.48 (9.25) | 11.79 (6.09) | 19.83 (9.38) | 17.75 (7.33) | 2.80 (2.36) | <.0001 | <.0001 |
| Hb at baseline, g/dL | 9.01 (1.21) | 8.59 (0.92) | 8.35 (1.17) | 9.31 (1.25) | 9.64 (1.06) | <.0001 | <.0001 |
| Hb at year 2, g/dL | 9.28 (1.14) | 8.78 (0.90) | 9.37 (1.22) | 9.44 (1.20) | 9.68 (1.07) | <.01 | <.01 |
| TRV at baseline, m/s | 2.40 (0.29) | 2.37 (0.34) | 2.41 (0.27) | 2.41 (0.26) | 2.41 (0.29) | .98 | .98 |
| TRV at baseline ≥2.5 m/s, n (%) | 69 (33.82) | 18 (31.03) | 12 (35.29) | 24 (33.33) | 15 (37.50) | .92 | .98 |
| TRV at year 2, m/s | 2.34 (0.28) | 2.39 (0.24) | 2.28 (0.25) | 2.30 (0.31) | 2.39 (0.27) | .02 | .04 |
| TRV at year 2 ≥2.5 m/s, n (%) | 56 (27.45) | 18 (31.03) | 7 (20.59) | 16 (22.22) | 15 (37.50) | .24 | .32 |
Unless otherwise noted, data are mean (standard deviation). Group differences were tested using Fisher’s exact test for categorical variables and analysis of variance or the Kruskal-Wallis test for continuous variables. Group 1: not on disease modifying therapy at baseline and 2-y evaluation; group 2: not on disease modifying therapy at baseline evaluation, but initiated hydroxyurea prior to the 2-y evaluation; group 3: on hydroxyurea at both baseline and 2-y evaluation; group 4: on monthly blood transfusions at both baseline and 2-y evaluation. HU, hydroxyurea; N/A, not applicable.