Table 4.

Health care utilization in relation to patients’ age and chronic pain status, and duration of prescription.

All participants (N = 113)
	Age groups (years)				Chronic pain
	<12	12–17	≥18	p Value	Yes	No	p Value
Emergency room, median (IQR)
All	1.1 (0.3–2.2)	1.1 (0–2.0)	0.24 (0–2.0)	.32	1.9 (1.1–5.0)	0.6 (0–1.8)	<.001
On HU	1 (0-2.2)	0.40 (0-2.0)	0.20 (0-1.5)	.58	2.17 (1–4.25)	0 (0–1.4)	.001
Hospitalization, median (IQR)
All
Stays a year	0.6 (0–1.4)	0.74 (0.4–1.8)	0.4 (0–1.6)	.57	1.6 (0.5–4.2)	0.4 (0–1.2)	.001
Length of stay	2.0 (0–7.6)	3.95 (1.2–9.4)	1.8 (0–7.0)	.44	9.6 (3.2–24)	1.8 (0–7.0)	<.001
On HU
Stays a year	0 (0–1.4)	0.5 (0–1.6)	0.2 (0–1.4)	.45	1.8 (0.43–3.5)	0 (0–1.0)	<.001
Length of stay	0 (0–6.4)	1.7 (0–8.6)	0.64 (0–7.8)	.53	9.64 (2.87–3.3)	0 (0–3.0)	<.001

Participants with HbSS (N = 99)
	Age groups (years)				Chronic pain
	<12	12–17	≥18	p Value	Yes	No	p Value
Emergency room, median (IQR)
All	0.9 (0–2.0)	1.1 (0–2.0)	0.24 (0–2.0)	.56	2.0 (1.5–4.0)	0.4 (0–1.8)	<.001
On HU	0 (0–2.2)	0.40 (0–2.0)	0.20 (0–1.4)	.66	2.33 (1.4–4.0)	0 (0–1.0)	<.001
Hospitalization, median (IQR)
All
Stays a year	0.4 (0–1.2)	0.74 (0.4–1.8)	0.4 (0–1.6)	.37	2.0 (0.8–4.4)	0.4 (0–1.2)	<.001
Length of stay	1.8 (0–6.4)	3.95 (1.2–9.4)	1.6 (0–6.9)	.25	15 (3.4–25.6)	1.4 (0–5.2)	<.001
On HU
Stays a year	0 (0–1)	0.5 (0–1.6)	0.2 (0–1.4)	.26	2.0 (0.8–4.0)	0 (0–0.74)	<.001
Length of stay	0 (0–3.6)	1.7 (0–8.7)	0.67 (0–6.4)	.28	15 (3.4–25.6)	0 (0–2.44)	<.001

p <.05 was statistically significant (highlighted in bold).

HU: hydroxyurea; IQR: inter-quartile range.

“All” is defined as entire follow up period, including being HU therapy; “On HU” is defined as the period being on HU.