Abstract
Purpose:
To determine the prevalence of sickle retinopathy in pediatric patients seen at Yale and to identify factors that modifies risk for the onset and progression of sickle retinopathy.
Methods:
A retrospective chart review and analysis of consecutive pediatric patients (ages 6-21) referred to Yale for sickle retinopathy from January 1, 2003 to December 31, 2012. 135 patients were reviewed for the onset of retinopathy, time to progression, gender, genotype, fetal hemoglobin (HgF) level, and history of monthly transfusions.
Results:
Of the 135 patients, 81 patients had SS genotype, 38 had SC genotype, and 15 had SB-thalassemia genotype. Among patients with SS genotype, 35 (43.2%) and 11(13.6%) had non-proliferative and proliferative sickle retinopathy respectively. The mean age at diagnosis was 13.4 (SD 6.16) for NPSR and 16.8 (SD 2.50) for PSR. Of the patients with SC genotype, 14 (36.8%) had NPSR and 12 (31.6%) had PSR with a mean age of diagnosis of 11.5 (SD 5.15) and 12.5 (SD 4.04) respectively.<br /> <br /> Patients with SS genotype were stratified by hemoglobin F (HgF) levels of 0 to 1.9 mg/dL, 2.0 to 4.6 mg/dL, 4.7 to 9.8mg/dL and ≥9.9mg/dL with 4, 13, 15 and 19 patients in each group respectively. Subjects undergoing monthly transfusions were excluded from the analysis. There was a 5.3 fold increase (CI 95% 1.9-14.9, p=0.001) in the incidence of sickle retinopathy in patients with HgF less than 4.0mg/dL. There was a statistically significant inverse correlation of sickle retinopathy with HbF levels using spearman correlation (r=-0.22, p=0.0028).<br /> <br /> Patients undergoing monthly scheduled transfusions had 7.07 fold (CI 95% 1.61 to 31.0, P=0.0096) decreased risk for progression of retinopathy while receiving treatment. The one patient who demonstrated progression despite monthly transfusions died secondary to complications related to her SCD.
Conclusions:
Our patient cohort agrees with previous studies with the tendency of the SC genotype having a more rapid onset and progression of SR compared to SS. Low HgF levels correlated with a statistically significant increased incidence of sickle retinopathy. Higher levels of HgF seem to be protective against onset and progression of SR. Patients undergoing monthly transfusions had a statistically significant reduction in risk for progression of disease. Progression in the setting of transfusion is rare and may be a poor prognostic indicator.