Table 1.
Hydroxycarbamide use of hospitalized patients with sickle cell disease-related conditions
| Characteristics | Overall, No. (Column %) | hydroxycarbamide exposed in the past 6 months before hospitalization | hydroxycarbamide unexposed in the past 6 months before hospitalization | p-value |
|---|---|---|---|---|
| Hospitalization, No. (%) | 20,721 | 4263 | 16458 | |
| Age, in years | ||||
| 0–17 | 5831 (28.1) | 1203 (28.2) | 4628 (28.1) | <.0001 |
| 18–29 | 6761 (32.6) | 1733 (40.7) | 5028 (30.6) | |
| 30–39 | 3125 (15.1) | 603 (14.1) | 2522 (15.3) | |
| 40–49 | 2299 (11.1) | 442 (10.4) | 1857 (11.3) | |
| 50+ | 2705 (13.1) | 282 (6.6) | 2423 (14.7) | |
| Sex | ||||
| Male | 8916 (43.0) | 1894 (44.4) | 7022 (42.7) | 0.0383 |
| Female | 11805 (57.0) | 2369 (55.6) | 9436 (57.3) | |
| ACS diagnosis code | ||||
| ACS | 1774 (8.6) | 336 (7.9) | 1438 (8.7) | 0.0752 |
| Pneumonia | 3574 (17.3) | 582 (13.7) | 2992 (18.2) | <.0001 |
| ACS or pneumonia | 4513 (21.8) | 781 (18.3) | 3732 (22.7) | <.0001 |
| Asthma diagnosis code | 2504 (12.1) | 486 (11.4) | 2018 (12.3) | 0.1242 |
| Year of admission | ||||
| 2009 | 2088 (10.1) | 363 (8.5) | 1725 (10.5) | <.0001 |
| 2010 | 3781 (18.3) | 691 (16.2) | 3090 (18.8) | |
| 2011 | 3979 (19.2) | 768 (18.0) | 3211 (19.5) | |
| 2012 | 4055 (19.6) | 938 (22.0) | 3117 (18.9) | |
| 2013 | 3407 (16.4) | 775 (18.2) | 2632 (16.0) | |
| 2014 | 3411 (16.5) | 728 (17.1) | 2683 (16.3) | |
| Season of admission | ||||
| Winter (Dec–Feb) | 4517 (21.8) | 928 (21.8) | 3589 (21.8) | 0.2177 |
| Spring (Mar–May) | 4661 (22.5) | 985 (23.1) | 3676 (22.3) | |
| Summer (Jun–Aug) | 5373 (25.9) | 1055 (24.7) | 4318 (26.2) | |
| Fall (Sep–Nov) | 6170 (29.8) | 1295 (30.4) | 4875 (29.6) | |
| Discharge day of the week** | ||||
| Weekend | 5002 (24.1) | 1087 (25.5) | 3915 (23.8) | 0.0200 |
| Weekday | 15719 (75.9) | 3176 (74.5) | 12543 (76.2) | |
| Erythrocyte transfusion during admission | 4553 (22.0) | 995 (23.3) | 3558 (21.6) | 0.0155 |
| Medication exposure | ||||
| Opioids | 9203 (44.4) | 3291 (77.2) | 5912 (35.9) | <.0001 |
| NSAIDs | 3756 (18.1) | 1422 (33.4) | 2334 (14.2) | <.0001 |
| Health services use in the past 6 months | ||||
| Hospitalization | ||||
| Mean, SD | 1.56 (2.28) | 2.06 (2.50) | 1.42 (2.20) | <.0001*** |
| Median, IQR | 1 (0–2) | 1 (0–3) | 1 (0–2) | <.0001**** |
| ER visits | ||||
| Mean, SD | 3.03 (6.80) | 3.32 (6.16) | 2.95 (6.96) | 0.0008*** |
| Median | 1 (0–3) | 2 (0–4) | 1 (0–3) | <.0001**** |
ACS, acute chest syndrome; NSAIDs, Nonsteroidal anti-inflammatory drugs; ER, emergency room;
*
High-dose hydroxycarbamide exposure defined by the median of the cumulative hydroxycarbamide dose among patients ever-exposed. Set at 90g across age groups. Any patient with > or equal to 90g cumulative dose over the 180 days preceding the index admission event is considered as high-dose hydroxycarbamide users.
**
Weekend discharge status defined as Saturday and Sunday, while the rest of the week were weekdays (Mon-Fri).
***
Students t-test for comparing means across exposed groups
****
Wilcoxon Rank sum test for comparing medians across exposed groups