Effects of vitamin D supplement therapy on clinical outcomes of intravitreal bevacizumab in diabetic macular edema

Purpose: : To evaluate the effects of oral vitamin D supplement administration on clinical outcomes of intravitreal bevacizumab administration in diabetic macular edemaMethods: : A total of 71 patients with the diagnosis of center involving DME were planned to receive three monthly intravitreal bevacizumab (IVB) injections. Those patients with less than 30 ng/ml of 25-OH vitamin D were divided into treatment and control groups. The treatment group members were treated with oral vitamin D, 50000 IU per week for 8 weeks. One month after the third IVB injection, changes of best corrected visual acuity (BCVA) and central macular thickness (CMT) were analyzed for each group. The primary outcome measures were changes of BCVA and CMT from baseline to one month after the third injection. Multiple linear regression analysis was performed to investigate the relationship between variables. Results: Thirty three patients were found to have a sufficient level of vitamin D, and 34 patients had insufficient levels. Nineteen patients with an insufficient level of vitamin D were treated with oral vitamin D and 15 patients entered in the control group. Average level of serum 25-OH vitamin D in all patients was 27.9 ng/ml, with a mean of 20.3 ± 5.4 and 17.3± 5.4 in control and treatment groups respectively. After three IVB injections, BCVA improved in all groups significantly but the difference between treatment and control groups was not significant. Also CMT decreased in all three groups significantly. The mean CMT decreased more in vitamin D treated group, but the difference was not statistically significant (p=0.29). Pearson correlation coefficient (-0.032) showed a significant negative correlation between serum vitamin D and HbA1c levels. Conclusion: : In patients with DME and vitamin D insufficiency, treatment with oral vitamin D supplement may have some beneficial effects on outcomes of IVB injections.