Risk factors associated with sickle cell retinopathy: findings from the Cooperative Study of Sickle Cell Disease

Table 1 Demographic and Clinical Characteristics of Study Cohort

Characteristic	Whole cohort	SCR			PSCR
Characteristic	n = 1904	Yes (n = 953) n (%)	No (n = 951) n (%)	P-value^a	Yes (n = 423) n (%)	No (n = 1481) n (%)	P-value^a
Age at entry
Median (years)^b	17.0 (10.0–26.0)	22.0 (14.0–29.0)	13.0 (7.0–21.0)	< 0.001	25.5 (18.0–32.0)	15.0 (8.0–23.0)	< 0.001
Adult	852 (44.7%)	567 (59.5%)	285 (30.0%)	< 0.001	315 (74.5%)	537 (36.3%)	< 0.001
Pediatric	1052 (55.3%)	386 (40.5%)	666 (70.0%)		108 (25.5%)	944 (63.7%)
Sex
Female	1051 (55.2%)	493 (51.8%)	558 (58.7%)	0.003	213 (50.5%)	838 (56.6%)	0.025
Male	851 (44.7%)	458 (48.2%)	393 (41.3%)		209 (49.5%)	642 (43.4%)
Race
Black	1864 (97.9%)	937 (98.8%)	927 (97.9%)	0 .103	419 (99.8%)	1445 (98.0%)	0.101
Other races	31 (1.6%)	11 (1.2%)	20 (2.1%)		1 (0.2%)	30 (2.0%)
Smoking	588 (30.9%)	400 (44.9%)	188 (25.6%)	< 0.001	216 (53.1%)	372 (30.6%)	< 0.001
Eye symptoms	446 (23.4%)	258 (27.1%)	188 (19.8%)	< 0.001	146 (34.5%)	300 (20.3%)	< 0.001
BP ≥ 130/90 (mmHg)	152 (8.0%)	101 (10.8%)	51 (5.6%)	< 0.001	55 (13.2%)	97 (6.8%)	< 0.001
BMI ≥ 25 (kg/m²)	183 (9.6%)	116 (12.7%)	67 (7.4%)	< 0.001	67 (16.5%)	116 (8.2%)	< 0.001
Genotype
SCA^c	1403 (73.7%)	682 (71.7%)	719 (75.8%)	0.041	253 (60.0%)	1148 (77.7%)	< 0.001
Variant^d	501 (26.3%)	269 (28.3%)	229 (24.2%)		169 (40.0%)	329 (22.3%)

SCR sickle cell retinopathy, PSCR proliferative sickle cell retinopathy, BMI body mass index, BP blood pressure
Significant associations are marked in bold (p < 0.05)
^aP-values determined using chi-square test for categorical variables and Mann–Whitney U test for continuous variables (age at entry)
^bMedian (interquartile range)
^cSickle cell anemia (SCA) genotypes include SS, Sβ0 and SSα
^dVariant genotypes include SC, Sβ + , other

ISSN: 2056-9920