Hydroxyurea effects on pain, dactylitis, ACS, and hospitalization
| . | Hydroxyurea, N = 96, n (%) . | Placebo, N = 97, n (%) . | P . |
|---|---|---|---|
| Pain | < .001* | ||
| Total events | 177 | 375 | |
| Subjects with 0 events | 34 (35) | 22 (23) | |
| Subjects with 1 event | 29 (30) | 15 (15) | |
| Subjects with 2 or 3 events | 20 (21) | 19 (20) | |
| Subjects with 4+ events | 13 (14) | 41 (42) | |
| Dactylitis | < .001† | ||
| Total events | 24 | 123 | |
| Subjects with 0 events | 82 (86) | 55 (57) | |
| Subjects with 1 event | 6 (6) | 14 (14) | |
| Subjects with 2 events | 6 (6) | 8 (8) | |
| Subjects with 3 events | 2 (2) | 6 (6) | |
| Subjects with 4+ events | 0 (0) | 14 (14) | |
| ACS events | .03† | ||
| Total events | 8 | 27 | |
| Subjects with 0 events | 89 (93) | 79 (82) | |
| Subjects with 1 event | 6 (6) | 10 (10) | |
| Subjects with 2 or 3 events | 1 (1) | 8 (8) | |
| Hospitalizations | .008* | ||
| Total events | 232 | 324 | |
| Subjects with 0 events | 27 (28) | 13 (13) | |
| Subjects with 1 event | 22 (23) | 16 (17) | |
| Subjects with 2 or 3 events | 26 (27) | 28 (29) | |
| Subjects with 4+ events | 21 (22) | 40 (41) |
| . | Hydroxyurea, N = 96, n (%) . | Placebo, N = 97, n (%) . | P . |
|---|---|---|---|
| Pain | < .001* | ||
| Total events | 177 | 375 | |
| Subjects with 0 events | 34 (35) | 22 (23) | |
| Subjects with 1 event | 29 (30) | 15 (15) | |
| Subjects with 2 or 3 events | 20 (21) | 19 (20) | |
| Subjects with 4+ events | 13 (14) | 41 (42) | |
| Dactylitis | < .001† | ||
| Total events | 24 | 123 | |
| Subjects with 0 events | 82 (86) | 55 (57) | |
| Subjects with 1 event | 6 (6) | 14 (14) | |
| Subjects with 2 events | 6 (6) | 8 (8) | |
| Subjects with 3 events | 2 (2) | 6 (6) | |
| Subjects with 4+ events | 0 (0) | 14 (14) | |
| ACS events | .03† | ||
| Total events | 8 | 27 | |
| Subjects with 0 events | 89 (93) | 79 (82) | |
| Subjects with 1 event | 6 (6) | 10 (10) | |
| Subjects with 2 or 3 events | 1 (1) | 8 (8) | |
| Hospitalizations | .008* | ||
| Total events | 232 | 324 | |
| Subjects with 0 events | 27 (28) | 13 (13) | |
| Subjects with 1 event | 22 (23) | 16 (17) | |
| Subjects with 2 or 3 events | 26 (27) | 28 (29) | |
| Subjects with 4+ events | 21 (22) | 40 (41) |
ACS indicates acute chest syndrome.
P value was derived from the χ2 test comparing difference in frequency of events between hydroxyurea and placebo groups.
P value was derived from the Fisher exact test comparing difference in frequency of events between hydroxyurea and placebo groups. There were a total of 374 patients-years of on study observation; the median follow-up was 2 years/patient.