Effects of Crocin on Diabetic Maculopathy: A Placebo-Controlled Randomized Clinical Trial

Abstract

Diabetic macular edema (DME) is one of the most important sight-threatening complications in patients with diabetes. Owing to neuroprotective properties, crocin, as the main constituent in saffron, is thought to be useful in the treatment and prevention of diabetic maculopathy. The aim of this trial was to evaluate the effects of crocin as a supplement on reducing inflammation in patients with diabetic maculopathy. Double-masked, placebo controlled, phase 2 randomized clinical trial. Participants: In this study, 101 eyes of 60 patients with refractory diabetic maculopathy to conventional therapy including macular photocoagulation and intravitreal injection of anti-vascular endothelial growth factor agent (bevacizumab) with or without steroid (triamcinolone) were studied in 3 groups. Patients in the crocin groups received 5mg or 15mg crocin tablets per day for 3months, whereas patients in the placebo group received 1 placebo tablet per day during the study. The best-corrected visual acuity (BCVA) and central macular thickness (CMT) were measured before, every month during, and 3months after intervention. Biochemical blood tests were also evaluated before and after trial. The BCVA and CMT were evaluated as the primary outcomes, whereas HbA1c and fasting blood sugar (FBS) were studied as the secondary outcomes in this trial. One hundred and one eyes were enrolled in this trial and were divided into 3 groups (crocin 5mg, n= 34; crocin 15mg, n= 33; and placebo, n= 34). According to our data, administration of crocin 15mg tablet per day could significantly decrease HbA1c (P value= .024; 95% confidence interval [CI] 0.3-0.96), and CMT (P value= .005; 95% CI, 32.75-126.99) and improve BCVA (logMAR changes; P value= .012; 95% CI, 0.23-0.69) compared to the placebo group. Although administration of crocin 5mg tablet per day could clinically improve HbA1c, FBS, CMT, and BCVA, the difference was not significant compared to the placebo group. This study indicated the effect of crocin as a potent antioxidant and neuroprotective for treatment of refractory DME in the short term; however, the clinical significance is yet to be proved in a study with larger sample size and longer duration of follow-up and also in treatment-naïve patients.