Table 2.

VOC prevalence distribution studies

Study identifier	Country	N	Mean age	VOC definition	Distribution of VOC, %
Adekile et al. [ 53]	Kuwait	396	19.2	Hospitalization	0/year: 3.3
					1/year: 54.8
					2–3/year: 13.2
					> 3/year: 18.9
Aloni et al. [54]	Democratic Republic of Congo	168	10	Hospitalization > 48 h	0/year: 3.6
					1–3/year: 51.8
					> 3/year: 44.6
Andemariam et al. [20]	U.S	384	30.1	Self-reported (patient survey; hospitalization, ED, managed at home)	0/year: 4
					1–4/year: 38
					≥ 5/year: 59
Bailey et al. [14]	England	15,076	30a	Healthcare visit (OP, IP, or ED)	≥ 3/year: 4
Dave et al. [47]	India	404	19	Healthcare visit (OP or IP) to care system	0/year: 11.9
					1/year: 15.6
					2/year: 22.8
					≥ 3/year: 49.8
Delicou et al. [23]	Greece	254	NR	Healthcare visit (OP, IP, or ED)	0/year: 25.3
					1–5/year: 50.6
					5–10/year: 8.3
					> 10/year: 15.8
James et al. [19]	Multiple	1513	24.1	Self-reported (patient survey; hospitalization, ED, managed at home)	0/year: 8
					1–4/year: 51
					≥ 5/year: 40
Latremouille-Viau et al. [49]	U.S	18,287b	28.5	Healthcare visit (OP, IP, or ED); Medicaid and Medicare claims	0/year: 36.1
					1/year: 17
					≥ 2/year: 46.8
		15,431c	48.2		0/year: 44.9
					1/year: 11.4
					≥ 2/year: 43.7
Rizio et al. [13]	U.S	303	34.4	Self-reported (ASCQ-Me)	0/year: 8.9
					1/year: 9.6
					2/year: 14.5
					3/year: 19.8
					≥ 4/year: 47.2
Shah et al. [22]	U.S	8521	32.9	Healthcare visit (OP, IP, or ED); Medicaid claims	0/year: 52.3
					1/year: 14.7
					2/year: 6.7
					3/year: 4.6
					4/year: 3.7
					5/year: 2.7
					6/year: 2
					7/year: 1.5
					8/year: 1.4
					9/year: 1.4
					> 10/year: 9.2
van Tuijn et al. [55]	Netherlands	95	37a	Hospitalization	0/year: 23
					0–1/year: 43
					> 1/year: 16

ASCQ-Me adult sickle cell quality of life measurement information system, ED emergency department, IP inpatient, NR not reported, OP outpatient, VOC vaso-occlusive crisis

^aMedian reported

^bMedicaid claims study arm

^cMedicare claims study arm