Table 3.

Adjusted models of readmission or acute care utilization following hospitalized for SCD-related conditions

Hydroxycarbamide exposure types	7-day SCD-related readmission			30-day SCD-related readmission			7-day all-cause readmission			30- day all-cause readmission			7-day all-cause acute care			30-day all-cause acute care
	OR (95%CI)		p	OR (95%CI)		p	OR (95%CI)		p	OR (95%CI)		p	OR (95%CI)		p	OR (95%CI)		p
Whole cohort (pediatric and adult patients)
High adherent user (PDC≥0.80)	0.54	0.36–0.82	0.0034	0.60	0.45–0.79	0.0003	0.52	0.34–0.78	0.0019	0.62	0.47–0.82	0.0007	0.51	0.37–0.70	<.0001	0.54	0.43–0.68	<.0001
Intermediate adherent users (0.80>PDC≥0.50)	0.67	0.47–0.95	0.0228	0.58	0.48–0.71	<.0001	0.65	0.46–0.92	0.0148	0.61	0.50–0.75	<.0001	0.66	0.51–0.85	0.0014	0.60	0.50–0.71	<.0001
Nonadherent user (PDC<0.50)
Reference
All adult (18+)
Ever-HC exposure*	0.96	0.76–1.21	0.7062	1.13	0.95–1.35	0.1782	0.94	0.75–1.18	0.6074	1.07	0.90–1.27	0.4362	0.88	0.74–1.05	0.147	1.07	0.93–1.23	0.3304
Never-exposed
Reference
Adult (18+) and with any hydroxycarbamide exposure
High-dose ( >1g daily)	0.72	0.47–1.11	0.1348	0.75	0.54–1.05	0.09	0.69	0.45–1.04	0.0767	0.72	0.52–0.99	0.0451	0.54	0.38–0.77	0.0006	0.65	0.49–0.86	0.0027
Intermediate-dose (0.5–1g daily)	0.87	0.56–1.36	0.5407	0.73	0.57–0.94	0.0157	0.86	0.56–1.30	0.4718	0.73	0.57–0.93	0.0122	0.83	0.61–1.13	0.2476	0.69	0.56–0.85	0.0005
Low-dose (0–90g, 0–500mg daily)
Reference
Adult (18+) and with any hydroxycarbamide exposure
Recent exposure	1.22	0.83–1.79	0.3105	0.99	0.82–1.19	0.896	1.25	0.86–1.84	0.2435	1.00	0.83–1.21	0.9846	1.28	0.98–1.67	0.0726	1.14	0.96–1.35	0.1345
No Exposure in last 3-months
Reference
High adherent user (PDC≥0.80)	0.66	0.36–1.20	0.0825	0.59	0.41–0.84	0.0002	0.60	0.33–1.10	0.0661	0.57	0.40–0.81	0.0005	0.56	0.36–0.89	0.0218	0.55	0.39–0.77	<.0001
Intermediate adherent users (0.80>PDC≥0.50)	0.71	0.48–1.05	0.1713	0.64	0.51–0.81	0.0040	0.70	0.48–1.02	0.0981	0.67	0.54–0.84	0.0020	0.71	0.53–0.95	0.0141	0.62	0.50–0.76	0.0006
Nonadherent user (PDC<0.50)
Reference

Abbreviations: SCD, sickle cell disease; OR, odds ratio; CI, confidence interval; HC, hydroxycarbamide

^*The ever-exposure term in this model can be interpreted as estimating the allocation bias between exposed and unexposed SCD patients

^**The High-dose vs. Low-dose hydroxycarbamide exposure term in this model stratified SCD patients into ≥90g and <90g cumulative dose in the 6 months’ period before the index admission event.

Analysis limited to adults, the outcome is SCD-related 30-day admission. Adjusted for age, gender, length of stay, cumulative opioids exposure (measured by oral morphine equivalent), NSAIDs exposure, transfusion during hospitalization, all-cause hospitalization in the previous 6 months, any ER visits in the previous 6 months, asthma diagnosis code, acute chest syndrome code, year of admission, season of admission, and weekday of discharge.

^aStatistically significant at the p < .05 level.