Dear Editor:

One of the most important complications of diabetes is retinopathy. Intravenous fluorescein angiography has been widely used for evaluation of diabetic retinopathy. Although numerous reports have been published about the iodinated contrast media induced nephropathy1-3, there is a few researches about renal injury secondary to fluorescein (as a noniodinated contrast media)4. In this investigation, we have been tried to evaluate effect of fluorescein sodium on the renal function among diabetic patients who have more susceptible to the renal injury compared with general population5.

This study was conducted on diabetic patients undergoing fluorescein angiography to assess retinopathy at the Department of Ophthalmology, Imam Khomeini Hospital, Ahvaz, Iran in 2006. Exclusion criteria were pregnancy, lactation, having received contrast media within 7 days of study entry, acute renal failure, endstage renal disease requiring dialysis, history of hypersensitivity reaction to contrast media, parenteral use of diuretics, and use or start of nonsteroidal anti-inflammatory drugs or angitansine receptor binding, or angiotansine converting enzyme inhibitor within 48 h of the procedure. The protocol was approved by the Ahvaz Jundishapur University of Medical Sciences. All patients provided informed, written consent. Upon fluorescein angiography, 500 mg sodium fluorescein solution was injected into the antecubital vein over 5 seconds. Serum creatinine (SCr) was measured before and on days 2 and 3 after the angiography. Renal injury was defined as a relative increase in SCr from the baseline of ≥25% or an absolute increase of ≥0.5 mg/dl during days 2 and 3. Data was analyzed by SPSS software, version 13. All data are presented as percentages or as mean ± standard deviation. The paired Student’s t test was used to compare SCr between various groups; and all p values <0.05 were considered statistically significant.

A total of 44 diabetic patients (22 male and 22 female) met the inclusion criteria and were studied; mean age of participants was 53.1 ± 9.2 years; range 30-72 years (male, 51.8 ± 9.5 and female, 54.3 ± 9.0; p = 0.38). Mean of SCr before fluorescein angiography was 1.09 ± 0.07 mg/dl (male, 1.13 ± 0.56 and female, 1.05 ± 0.40; p = 0.60), and after angiography was 1.16 ± 0.08 mg/dl (male, 1.23 ± 0.62 and female, 1.11 ± 0.50; p = 0.49). Nine patients (20.5%) had an increase in SCr from baseline within 72 hours of fluorescein administration (7 male and 2 female). In the present study, we did not observe any significant adverse effects after fluorescein usage.

Although, Kameda and colleagues use the estimated glomerular filtration rate to show renal injury secondary to fluorescein sodium and did not find any hardly effects on renal function4, but current study demonstrated that fluorescein could cause to renal injury in diabetic patients following angiography. Because lack of enough data, prospective studies will be required to determine whether fluorescein angiography is associated with higher incidence of adverse effects on renal function especially in diabetic patients.