SCD Patients (N = 3368)
	N	%
Demographic Characteristics
Age (Mean±SD, Year)	21.4 ± 14.9
Age Groups
2–12	1231	36.6
13–17	407	12.1
18–24	524	15.6
25–34	555	16.5
35–44	335	10.0
45–54	234	7.0
55–63	82	2.4
Gender
Female	1832	54.4
Male	1536	45.6
Race/Ethnicity
African American	2386	70.8
Caucasian	97	2.9
Hispanic	181	5.4
Asian	23	0.7
Others/unknown	681	20.2
Clinical Characteristics
Nonstudy SCD-Related Medication Use
Medication
Penicillin	1399	41.5
Folic acid	1272	37.8
Total number of nonstudy SCD medications
None	1354	40.2
1 (either penicillin or folic acid)	1357	40.3
2 (both penicillin and folic acid)	657	19.5
Blood Transfusion
Yes	204	6.1
No	3164	93.9
SCD-Related Complicationsa
Mean±SD	2.5 ± 2.5
Yes	2669	79.3
No	699	20.8
SCD-Related Comorbiditiesa
Mean±SD	0.5 ± 1.0
0	2377	70.6
1	549	16.3
2	225	6.7
3+	217	6.4
Charlson Comorbidity Index Scores
Mean±SD	1.1 ± 1.8
0	1675	49.7
1	913	27.1
2+	780	23.2