Abstract
Purpose :
To assess whether carrying sickle cell trait (SCT) is associated with increased severity of diabetic retinopathy (DR).
Methods :
Retrospective study of 200 eyes of 100 patients with Diabetes Mellitus (DM) carrying SCT and 200 eyes of 100 control patients with DM without SCT, identified through search of medical records based on diagnostic coding. Difference in the prevalence of either proliferative (P) diabetic retinopathy (DR) or clinically significant diabetic macular edema (CSME) between patients and controls was calculated. Differences visual acuity, ocular comorbidities, intraocular pressure, past ocular surgeries, glycemic control as assessed by random blood glucose measurement, nephropathy, hyperlipidemia and hypertension between diabetes mellitus (DM) patients carrying SCT versus DM only, were assessed.
Results :
Carriers of SCT had shorter duration of DM (median 15 vs 20 years, 25% quartile 8.3 and 14.7 years, respectively, P <0.001) and presented with better metabolic control (mean difference 1.6 mmol/dl, 95% CI 0.1-3.3, P=0.03). Ocular comorbidity, visual acuity and intraocular pressure in two groups were not significantly different. The frequency of past cataract surgery was higher in carriers of SCT (N=67 vs N=42, P<0.001). Eyes of carriers of SCT had a lower prevalence of advanced stages of DR (P<0.001). The prevalence of either PDR or DME in eyes of carriers of SCT was in 58% and in eyes of diabetic without STC was 95%. The difference was significant. (P<0.001).
Logistic regression analysis showed that absence of SCT (Adjusted Odds Ratio [AOR] = 24 with 95% CI = 8-72, P<0.001) and longer duration of DM (AOR = 1.1 with 95% CI = 1.02–1.13, P=0.003) were independent predictors of advanced stages of DR, whereas lack of hypertension (AOR = 0.5 with 95% CI= 0.2-0.9, P=0.02) and lack of diabetic nephropathy (AOR = 0.2 with 95% CI= 0.1-0.5, P<0.001) were independent protectors of advanced stages of DR.
Conclusions :
Carrying SCT may protect against the development and progression of DR. This may have implications for monitoring of DR and screening intervals. Further prospective study is needed to confirm this observed association.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.